Petroleum Calcs

Oil bubble-point pressure (Standing or Vasquez-Beggs).

Inputs: Rs, gasGravity, apiGravity, tempF, correlation. -> pb_psia.

Solution GOR Rs at pressure (Standing or Vasquez-Beggs).

Inputs: P, gasGravity, apiGravity, tempF, correlation. -> rs_scf_stb.

Saturated oil FVF Bo (Standing or Vasquez-Beggs).

Inputs: Rs, gasGravity, apiGravity, tempF, correlation. -> bo_rb_stb.

Dead-oil viscosity, Beggs-Robinson (1975), cp.

Inputs: apiGravity, tempF. Returns mu_od_cp.

Live oil viscosity (Beggs-Robinson; undersaturated via Vasquez).

Inputs: Rs, apiGravity, tempF; pressure+bubblePoint together for P>Pb.

Gas pseudo-criticals Ppc/Tpc from gravity, Sutton (1985).

Inputs: gasGravity. Returns ppc_psia, tpc_R.

Gas Z-factor, Dranchuk-Abou-Kassem (1975) + Sutton criticals.

Inputs: P, tempF, gasGravity. Returns z.

Gas formation volume factor Bg (rcf/scf) from DAK Z.

Inputs: P, tempF, gasGravity. Returns bg_rcf_scf.

Gas viscosity, Lee-Gonzalez-Eakin (1966), cp.

Inputs: P, tempF, gasGravity. Returns mu_g_cp.

Arps (1945) decline rate q(t): exponential/hyperbolic/harmonic.

Inputs: qi, Di (nominal, per t unit), b (0..2), t. b=0 exp, b=1 harmonic.

Arps (1945) cumulative production Np(t).

Inputs: qi, Di (nominal, per t unit), b (0..2), t. Returns np.

Arps EUR to an economic-limit rate qLimit.

Inputs: qi, Di, b, qLimit. Returns eur.

Fit Arps qi/Di/b to rate-time data by least squares.

Inputs: t[], q[] (>=3 pts). Returns qi, Di, b, rmse, r2.

Modified-hyperbolic (Robertson) rate with terminal exponential.

Inputs: qi, Di, b, Dlim (<Di), t. Returns q, segment, tLim.

Modified-hyperbolic EUR to an economic-limit rate qLimit.

Inputs: qi, Di, b, Dlim, qLimit. Returns eur.

Duong (2011) rate for fracture-dominated shale decline.

Inputs: q1, a, m, t. Returns q.

Score production forecasts with MAE, RMSE, MAPE, sMAPE, bias, cumulative error, and SPEE.

Null means unreported, never zero. Cumulative metrics use aligned pairs only.

Score production quantiles: pinball loss, calibration, interval coverage, and crossings.

Quantiles are in (0,1); forecast arrays align with actual. Null means missing.

Fit DCA models before a cutoff, score the holdout without leakage, and rank them.

Six models; missing rates stay null and skipped or failed runs include reasons.

Consequences of an asserted Arps decline: next-12/24 vs trailing, EUR, terminal switch.

di is NOMINAL MONTHLY. Assert oil and/or gas. No history = not yet producing.

Water formation volume factor Bw (McCain 1990).

Inputs: p, T.

Solution gas-water ratio Rsw (McCain 1990), scf/bbl.

Inputs: p, T, salinity_wt?.

Water isothermal compressibility - gas-free (undersaturated) (Osif/McCain), 1/psi.

Inputs: p, T, salinity_gL? (g/L NaCl) or salinity_mgL?.

Water isothermal compressibility - gas-saturated (McCain 1990), 1/psi.

Inputs: cw_gasfree, Rsw.

Brine (water) viscosity (McCain 1990), cp.

Inputs: p, T, salinity_wt?.

Brine density at reservoir conditions (McCain 1990), lb/ft³.

Inputs: salinity_wt, Bw.

Gas-oil interfacial tension at pressure (Baker & Swerdloff, 1956), dynes/cm.

Inputs: API, T, p.

Gas-oil interfacial tension (Abdul-Majeed & Abu Al-Soof, 2000), dynes/cm.

Inputs: API, T, Rs.

Wichert-Aziz (1972) non-hydrocarbon (H2S/CO2) correction to pseudo-criticals.

Inputs: Tpc, Ppc, yCO2?, yH2S?.

Glaso (1980) bubble-point pressure, psia.

Inputs: Rs, gas_sg, API, T.

Al-Marhoun (1988) bubble-point pressure, psia (Saudi/Middle-East crudes).

Inputs: Rs, gas_sg, API, T.

Petrosky-Farshad (1993) bubble-point pressure, psia (Gulf of Mexico).

Inputs: Rs, gas_sg, API, T.

Glaso (1980) solution GOR Rs at p ≤ Pb, scf/STB (inverse of the Pb form).

Inputs: p, gas_sg, API, T.

Glaso (1980) oil formation volume factor Bo at/below Pb, rb/STB.

Inputs: Rs, gas_sg, API, T.

Al-Marhoun (1988) oil formation volume factor Bo, rb/STB.

Inputs: Rs, gas_sg, API, T.

Petrosky-Farshad (1993) oil formation volume factor Bo, rb/STB (GOM).

Inputs: Rs, gas_sg, API, T.

Dindoruk-Christman (2004) bubble-point pressure, psia (GOM crudes).

Inputs: Rs, gas_sg, API, T.

Undersaturated oil isothermal compressibility (Vasquez-Beggs, 1980), 1/psi.

Inputs: Rsb, T, gas_sg, API, p.

Saturated (below-Pb) oil isothermal compressibility.

Inputs: p, T, API, Rsb.

Glaso (1980) dead-oil viscosity, cp.

Inputs: API, T.

Egbogah-Jack (1990) dead-oil viscosity, cp (Egbogah-Ng modified Beggs-Robinson).

Inputs: API, T.

Gas material balance p/z plotting variable for reservoir depletion analysis. [Craft & Hawkins Ch.6]

Inputs: p, z.

OGIP from p/z material balance: G = Gp/(1 - (p/z)/(p_i/z_i)). [Craft & Hawkins Ch.6]

Inputs: p_i, z_i, p, z, Gp.

Modified p/z for geopressured gas (Ramagost & Farshad, SPE 10125).

Inputs: p, z, p_i, c_w, c_f, S_wi.

Predict Gp at pressure (volumetric gas): Gp = G*(1 - (p/z)/(p_i/z_i)).

Inputs: G, p_i, z_i, p, z.

Predict pressure at Gp (volumetric gas): p/z = (p_i/z_i)*(1 - Gp/G).

Inputs: G, p_i, z_i, Gp, z?.

Ultimate gas recovery factor at abandonment: RF = 1 - (p_a/z_a)/(p_i/z_i).

Inputs: p_i, z_i, p_a, z_a.

Two-phase FVF Bt = Bo + (Rs_i - Rs)*Bg.

Inputs: Bo, Bg, Rs_i, Rs.

Underground withdrawal F (Havlena-Odeh): F = Np*[Bo+(Rp-Rs)*Bg]+Wp*Bw, Rp=Gp/Np.

Inputs: Np, Gp, Bo, Bg, Rs, Wp?, Bw?.

Oil + dissolved-gas expansion Eo = (Bo-Bo_i)+(Rs_i-Rs)*Bg.

Inputs: Bo, Bo_i, Bg, Rs_i, Rs.

Gas-cap expansion Eg = Bt_i*(Bg/Bg_i - 1).

Inputs: Bt_i, Bg, Bg_i.

Material balance formation and connate water expansion term Efw (MBE).

Inputs: m, Bt_i, c_w, c_f, S_wi, p_i, p.

Undersaturated oil compressibility: c_o = -(Bo-Bo_i)/(Bo_i*(p-p_i)).

Inputs: Bo_i, Bo, p_i, p.

Real-gas compressibility: c_g = 1/p - (1/z)*(dz/dp) (or 1/p ideal).

Inputs: p, z?, dz_dp?.

Total system compressibility: c_t = c_o*S_o + c_w*S_w + c_g*S_g + c_f.

Inputs: c_o, S_o, c_w, S_w, c_g?, S_g?, c_f.

Effective undersaturated-oil compressibility: c_e = (c_o*S_o+c_w*S_wi+c_f)/(1-S_wi).

Inputs: c_o, S_o, c_w, S_wi, c_f.

Fetkovich radial J = 0.00708*k*h*f/(mu_w*(ln(r_aR)-0.75)).

Inputs: k, h, mu_w, r_aR, f?.

Fetkovich linear aquifer J: 0.001127*k*w*h/(mu_w*L); boundary no-flow uses 0.003381.

Inputs: k, w, h, mu_w, L, boundary? (constant-pressure default | no-flow).

Fetkovich max encroachable water Wei = c_t*W_i*p_i.

Inputs: c_t, W_i, p_i.

Fetkovich initial aquifer water volume (radial): W_i = (pi/5.615)*(r_a^2-r_o^2)*h*phi*f.

Inputs: r_a, r_o, h, phi, f?.

Fetkovich average aquifer pressure: p_aq = p_i*(1 - We/Wei).

Inputs: p_i, We, Wei.

Fetkovich incremental influx step: dWe = (Wei/p_i)*(p_a_prev - p_R)*[1-exp(-J*p_i*dt/Wei)].

Inputs: Wei, p_i, p_a_prev, p_R, J, dt, We_prev?.

Schilthuis steady-state rate: q_w = C*(p_i - p).

Inputs: C, p_i, p.

Schilthuis cumulative influx: We = C*Σ(p_i - p_j)*dt_j.

Inputs: C, p_i, pressures, dt.

van Everdingen-Hurst dimensionless r_D, t_D (t in days), aquifer constant U.

Inputs: r_a, r_o, k, t, phi, mu_w, c_t, h, f?.

vEH water influx (single Δp step): We = U*Δp*Q(t_D).

Inputs: U, dp, Q_tD.

Pot aquifer: pore volume W_aq and instantaneous influx We = (c_w+c_f)*W_aq*(p_i-p).

Inputs: r_a, r_o, h, phi, c_w, c_f, p_i, p, f?.

Gas Z and Bg for sour gas: Sutton pseudo-criticals, Wichert-Aziz correction, DAK.

Inputs: P, tempF, gasGravity, yCO2?, yH2S?. Equals pvt_gasZ when sweet.

Black-oil PVT table over a pressure sweep: Rs, Bo, Bg, Z, Bw, viscosities per pressure.

pb sets the phase switch; Rsb follows the correlation at pb. Sweep 14.7..1.5*pb.

Havlena-Odeh straight line from pressure surveys: N, residuals, optional pot-aquifer fit.

Surveys: p, Np, Gp; PVT per survey or a fluid. fitAquifer solves N and we_mult.

Campbell plot from pressure surveys: F/Etot vs Np; flat = closed tank at N, rising = influx.

Same inputs as mbe_havlenaOdehFit; reports the trend and a diagnosis.

Cole plot for dry gas: Gp*Bg/(Bg-Bgi) vs Gp; flat = volumetric at G, rising = water drive.

Surveys need p, Gp; z per survey or gasGravity+tempF (+yCO2/yH2S) to compute Z.

Brooks-Corey capillary pressure from water saturation (drainage).

Inputs: Sw, Swi, Pd, lambda.

Brooks-Corey water saturation from capillary pressure (inverse).

Inputs: Pc, Swi, Pd, lambda.

van Genuchten capillary pressure from water saturation.

Inputs: Sw, Swr, alpha, n, m?.

van Genuchten water saturation from capillary pressure (inverse).

Inputs: Pc, Swr, alpha, n, m?.

Leverett J-function from capillary pressure.

Inputs: Pc, sigma, theta, k, phi, constant?.

Capillary pressure from Leverett J-function (inverse).

Inputs: J, sigma, theta, k, phi, constant?.

Normalized water saturation (Corey/effective saturation) for a water-oil system.

Inputs: Sw, Swc, Sorw.

Corey water relative permeability (water-oil system).

Inputs: Sw, Swc, Sorw, nw, krwMax?.

Corey oil relative permeability (water-oil system).

Inputs: Sw, Swc, Sorw, no, kroMax?.

Corey gas relative permeability (gas-oil / gas-liquid system, drainage).

Inputs: Sg, Sgc, Sorg, Swc, ng, krgMax?.

Newman (1973) pore-volume compressibility - consolidated sandstone correlation.

Inputs: phi.

Newman (1973) pore-volume compressibility - consolidated limestone correlation.

Inputs: phi.

Hall (1953) pore-volume (formation) compressibility correlation.

Inputs: phi.

Amott-Harvey wettability index.

Inputs: Vwsp, Vwf, Vosp, Vof.

Total saturation closure check / oil saturation helper.

Inputs: Sw, Sg?.

Plane-strain modulus E' = E/(1-nu^2). [Economides & Nolte, Reservoir Stimulation 3rd ed.]

Inputs: E, nu.

PKN wellbore (max) fracture width, in. Perkins-Kern field form (Economides PPS).

Inputs: q bpm (total), mu cp, xf ft, Eprime psi. Returns width_in.

PKN average fracture width. w_avg = (pi/4)*(4/5)*w_w ≈ 0.628*w_w.

Inputs: q, mu, xf, Eprime.

PKN net (treating) pressure at wellbore.

Inputs: Eprime, width_ft, hf.

PKN fracture volume (one wing pair, two wings, total) using ellipsoidal cross-section.

Inputs: xf, hf, width_avg_ft.

PKN fracture half-length WITHOUT leakoff (efficiency = 1): all injected fluid stored.

Inputs: q, t, hf, width_avg_ft.

PKN fracture half-length WITH Carter leakoff (Carter 1957 constant-width solution).

Inputs: q, t, hf, width_avg_ft, CL.

KGD wellbore (max) width, in. Geertsma-de Klerk field form (Economides PPS).

Inputs: q bpm (total), mu cp, xf ft, hf ft, Eprime psi. Returns width_in.

KGD average width. w_avg = (pi/4)*w_w (elliptical horizontal cross-section).

Inputs: q, mu, xf, hf, Eprime.

KGD net pressure. p_net = E'*w_w/(4*x_f) (Sneddon plane-strain crack).

Inputs: Eprime, width_ft, xf.

KGD fracture volume. V_f = 2*x_f*h_f*w_avg [ft^3]. [volume balance]

Inputs: xf, hf, width_avg_ft.

KGD half-length WITHOUT leakoff. x_f = q*t/(2*h_f*w_avg) [ft]. [volume balance]

Inputs: q, t, hf, width_avg_ft.

KGD half-length WITH Carter leakoff (Carter 1957 constant-width solution).

Inputs: q, t, hf, width_avg_ft, CL.

Radial (penny-shaped) wellbore (max) width, in (Geertsma-de Klerk).

Inputs: q bpm, mu cp, R ft, Eprime psi. Returns width_in.

Radial average width. w_avg = (8/15)*w_w (Geertsma-de Klerk radial model).

Inputs: q, mu, R, Eprime.

Radial net pressure of a uniform-pressure (Sneddon) penny crack, pi*E'*w_max/(8R).

width_ft = Sneddon max width, not the GdK frac_radial_width_wellbore.

Radial fracture volume. V_f = pi*R^2*w_avg (w_avg from frac_radial_width_average).

Inputs: R, width_avg_ft.

Radial fracture radius WITHOUT leakoff. q*t = pi*R^2*w_avg -> R = sqrt(q*t/(pi*w_avg)).

Inputs: q, t, width_avg_ft.

Radial fracture radius WITH Carter leakoff (Carter 1957 constant-width solution).

Inputs: q, t, width_avg_ft, CL.

Viscosity-controlled leakoff coefficient C_v (filtrate invasion, Carter region I).

Inputs: k md, phi, dp psi, mu cp. Returns ft/min^0.5.

Compressibility-controlled (reservoir) leakoff coefficient C_c (Carter region III).

Inputs: dp psi, k md, phi, ct 1/psi, mu cp. Returns ft/min^0.5.

Combined Carter leakoff coefficient from series resistances.

Inputs: Cv, Cc, Cw?.

Carter leakoff velocity at exposure time tau: u_L = C_L / sqrt(tau) [ft/min].

Inputs: CL, tau.

Cumulative Carter leakoff volume per unit fracture area exposed for time t.

Inputs: CL, t, area, Sp?, faces?.

Fluid efficiency eta = V_fracture / V_injected (stored fraction).

Inputs: V_fracture, V_injected.

Stokes terminal (single-particle) settling velocity in laminar regime (Re<1).

Inputs: dp_in, rho_p, rho_f, mu.

Hindered settling (Richardson & Zaki 1954): v_h = v_s * (1 - C)^n.

Inputs: vs, C, n?.

Particle Reynolds number Re_p = rho_f * v * d_p / mu (dimensionless).

Inputs: rho_f, v_ft_s, dp_in, mu.

Transport (placement) ratio = horizontal slurry velocity / settling velocity.

Inputs: v_horizontal, v_settling.

Wall (channel) correction factor for settling between parallel fracture faces.

Inputs: dp_in, width_in.

Dimensionless fracture conductivity C_fd = (k_f * w) / (k * x_f).

Inputs: kf, w_ft, k, xf.

Equivalent skin factor of a fractured vertical well.

Inputs: Cfd, xf, rw.

Critical-flow wellhead pressure upstream of a bean choke.

Pressure in psia; gauge-fit correlations use atmosphericPressure_psia (14.696).

Liquid rate through a bean in critical flow, inverted from.

Pressure in psia; gauge-fit correlations use atmosphericPressure_psia (14.696).

Bean size (64ths-inch) needed to pass a target rate at a given wellhead.

Pressure in psia; gauge-fit correlations use atmosphericPressure_psia (14.696).

Sonic (critical) gas rate through a choke, field units. From the standard.

Subcritical (incompressible) liquid flow through a choke/bean using the.

Sachdeva et al. (1986) two-phase critical pressure ratio y_c, solved by.

Sachdeva et al. (1986) two-phase mass flux + rate through a choke (SPE 15657).

Gas pipeline flow rate from inlet & outlet pressures.

Gas pipeline outlet pressure from a known flow rate.

Gas density at flowing pipeline conditions, real-gas law (field units)

Actual gas velocity in a pipe, field units. Convert standard rate to actual.

Gas Reynolds number, field units (dimensionless). Standard pipeline form.

Liquid velocity in a pipe, field units.

Liquid Reynolds number, field units (dimensionless)

Single-phase liquid frictional pressure drop in a horizontal pipe via.

Liquid pipeline outlet pressure = inlet - frictional ΔP.

Liquid pipeline inlet pressure = outlet + frictional ΔP.

Liquid flow rate from a known frictional ΔP. Because the Moody friction.

Vogel (1968) two-phase IPR forward rate from pwf given qmax (or a test point).

Inputs: pr, pwf, qmax?, qTest?, pwfTest?.

Vogel (1968) qmax (AOF) from a single (q,pwf,pr) test point below bubble point.

Inputs: pr, q, pwf.

Straight-line productivity index J = q/(pr - pwf) (single-phase, pwf > pb).

Inputs: q, pr, pwf.

Straight-line rate q = J(pr - pwf) for undersaturated single-phase flow.

Inputs: J, pr, pwf.

Composite IPR: straight-line above pb + Vogel below pb, using J at bubble point.

Inputs: J, pr, pb, pwf.

Fetkovich (1973) forward rate q = C(pr^2 - pwf^2)^n given C and n.

Inputs: C, n, pr, pwf.

Fetkovich (1973) C,n fit from >=2 flow-after-flow test points (log-log regression).

Inputs: pr, points, pwf.

Standing (1970) Vogel extension using flow efficiency FE (damaged/stimulated).

Inputs: pr, pwf, FE, qmaxFE1.

Wiggins (1993) three-phase oil IPR (generalized Vogel coefficients).

Inputs: pr, pwf, qmax.

Jones (1976) quadratic IPR rate from pr - pwf = a*q + b*q^2 (Darcy + turbulence).

Inputs: a, b, pr, pwf.

Jones (1976) a,b fit from >=2 test points: (pr - pwf)/q = a + b*q (linear).

Inputs: pr, points, pwf.

Darcy semi-steady-state radial oil rate (field units), STB/d.

Inputs: k, h, pr, pwf, mu, Bo, re, rw, s?.

Darcy pseudo-steady-state radial gas rate (field units), Mscf/d.

Inputs: k, h, pr, pwf, mu, z, T, re, rw, s?.

Joshi (1988) horizontal-well steady-state oil rate (field units), STB/d.

Inputs: k, kv?, h, L, reH, pr, pwf, mu, Bo, rw.

Absolute open flow (AOF) at pwf=0 for Vogel and Fetkovich IPR forms.

Inputs: form, qmax?, C?, n?, pr?.

CO2 partial pressure from gas composition: pCO2 = y_CO2 * P_total.

de Waard-Milliams-Lotz (1991) CO2 corrosion rate (mm/yr) of carbon steel.

de Waard-Milliams (1975) ORIGINAL nomogram CO2 corrosion rate (mm/yr).

CO2 fugacity correction for high pressure (de Waard et al.). Above ~250 bar.

Classify a corrosion rate (mm/yr) into NACE-style severity bands.

API RP 14E erosional (limiting) velocity: Ve = C / sqrt(rho_mix) [ft/s].

Check an operating velocity against the API RP 14E erosional limit. Reports.

Minimum pipe internal diameter (in) to keep the mixture velocity at or below.

No-slip two-phase mixture density (lb/ft3)

Actual mixture (superficial) velocity in a pipe.

Hammerschmidt (1934) hydrate-temperature depression (deg F)

Required inhibitor concentration (wt% in the aqueous phase) to achieve a.

Required METHANOL injection rate (mass and volume) to dose the free water to.

Required MEG (monoethylene glycol) injection rate (mass and volume) to dose.

Hydrate subcooling (driving force), deg F.

SEDM rate q(t) = qi * exp(-(t/tau)^n). Field units.

Inputs: qi, tau, n, t.

SEDM cumulative Q(t) = (qi*tau/n) * gamma(1/n, (t/tau)^n), lower incomplete gamma.

Inputs: qi, tau, n, t.

SEDM ultimate recovery (t -> infinity) = qi*tau*Gamma(1+1/n) = (qi*tau/n)*Gamma(1/n).

Inputs: qi, tau, n.

Fit SEDM (qi, tau, n) to rate-time data by least squares (grid then refine).

Inputs: t, q.

PLE rate q(t) = qi * exp(-Dinf*t - D1*t^n). Field units.

Inputs: qi, Dinf, D1, n, t.

PLE cumulative Q(t) = integral(0..t) qi*exp(-Dinf*s - D1*s^n) ds (Simpson, no closed form).

Inputs: qi, Dinf, D1, n, t, panels?.

Fit PLE (qi, Dinf, D1, n) to rate-time data by least squares (grid then refine).

Inputs: t, q.

LGM cumulative Q(t) = K * t^n / (a + t^n). Field units; K = carrying capacity = EUR.

Inputs: K, a, n, t.

LGM rate q(t) = dQ/dt = K*a*n*t^(n-1) / (a + t^n)^2. Field units.

Inputs: K, a, n, t.

LGM instantaneous rate as the analytic derivative of cumulative q = dQ/dt (alias of dca_lgmRate).

Inputs: K, a, n, t.

LGM EUR = K (the carrying capacity; cumulative as t -> infinity).

Inputs: K.

Fit LGM (K, a, n) to cumulative-time data by least squares (grid then refine).

Inputs: t, Q.

Duong cumulative Q(t) = q(t) / (a * t^(-m)), the closed-form integral of the Duong rate.

Inputs: q1, a, m, t.

Duong EUR to an economic-limit rate qLimit: solve q(t)=qLimit for t.

Inputs: q1, a, m, qLimit.

Fit Duong (a, m, q1) to rate-time data. For candidate (a,m) the points line up.

Inputs: t, q.

Effective (secant) decline from nominal (instantaneous) decline.

Inputs: Dnom, b?.

Nominal (instantaneous) decline from effective (secant) decline.

Inputs: Deff, b?.

Instantaneous Arps b-factor from three (t,q) points: b = d(1/D)/dt, with the.

Inputs: t, number, number], q, number, number].

Beta-derivative diagnostic beta = t * (d ln q / d t), the log-log slope of rate.

Inputs: t, q, at.

EUR for an Arps-hyperbolic that switches to terminal exponential at decline Dlim.

Inputs: qi, Di, b, Dlim, qLimit.

Calculates pure-component PR or SRK cubic EOS A, B, a, and b.

Inputs: eos, Tc_degR, Pc_psia, omega, T_degR, P_psia.

Solves the PR or SRK cubic EOS compressibility-factor equation.

Inputs: eos, A_dimless, B_dimless.

Calculates pure-component fugacity coefficient from PR or SRK Z, A, and B.

Inputs: eos, Z, A_dimless, B_dimless.

Calculates gas or liquid molar volume from Z, T, and P in field units.

Inputs: Z, T_degR, P_psia.

Calculates mass density from Z, T, P, and molar mass in field units.

Inputs: Z, T_degR, P_psia, molarMass_lb_per_lbmol.

Calculates pure-component cubic-EOS residual enthalpy departure.

Inputs: eos, Tc_degR, Pc_psia, omega, T_degR, P_psia, Z.

Calculates pure-component cubic-EOS residual entropy departure.

Inputs: eos, Tc_degR, Pc_psia, omega, T_degR, P_psia, Z.

Calculates isothermal compressibility from a cubic EOS Z root.

Inputs: eos, Z, A_dimless, B_dimless, P_psia.

Estimates Wilson K-values for a multicomponent feed.

Inputs: Tc_degR, Pc_psia, omega, T_degR, P_psia, componentNames?.

Solves Rachford-Rice vapor fraction and phase compositions.

Inputs: z, K, tolerance?, maxIter?.

Runs an approximate two-phase PR or SRK flash by successive substitution.

Inputs: eos, z, Tc_degR, Pc_psia, omega, T_degR, P_psia, kij?, componentNames?,…

Computes ESP total dynamic head from lift, friction, and wellhead pressure.

Inputs: netVerticalLift_ft, wellheadPressure_psia, fluidGradient_psiPerFt, refe…

Computes the integer ESP stage count required to develop a target head.

Inputs: totalDynamicHead_ft, headPerStage_ft, stageSafetyFactor?.

Applies centrifugal-pump affinity laws for speed and impeller trim changes.

Inputs: baseFlowRate_bpd, baseHead_ft, baseBrakeHorsepower_hp, baseSpeed, newSp…

Computes ESP brake horsepower by hydraulic power or stage horsepower.

Inputs: flowRate_bpd?, totalDynamicHead_ft?, fluidSpecificGravity?, pumpEfficie…

Computes available NPSH at an ESP intake from pressure head above vapor.

Inputs: intakePressure_psia, vaporPressure_psia, fluidGradient_psiPerFt, static…

Computes ESP motor loading from required brake horsepower and nameplate hp.

Inputs: requiredBrakeHorsepower_hp, motorNameplateHorsepower_hp, motorServiceFa…

Computes sucker-rod pump displacement from speed, plunger size, and stroke.

Inputs: strokesPerMinute_spm, plungerDiameter_in, effectivePlungerStroke_in.

Computes effective plunger stroke from elastic stroke losses and overtravel.

Inputs: polishedRodStroke_in, rodStretch_in, tubingStretch_in, overtravel_in?.

Computes rod-string elastic stretch under fluid load by Hooke's law.

Inputs: fluidLoad_lbf, rodLength_ft, rodDiameter_in?, rodArea_in2?, modulusElas…

Computes peak polished-rod load using the Mills acceleration approximation.

Inputs: fluidLoad_lbf, rodStringWeight_lbf, polishedRodStroke_in, pumpingSpeed_…

Computes minimum polished-rod load using the Mills acceleration approximation.

Inputs: rodStringWeight_lbf, polishedRodStroke_in, pumpingSpeed_spm.

Computes approximate ideal counterbalance effect from polished-rod loads.

Inputs: peakPolishedRodLoad_lbf, minimumPolishedRodLoad_lbf.

Computes polished-rod horsepower from an approximate rectangular card area.

Inputs: peakPolishedRodLoad_lbf, minimumPolishedRodLoad_lbf, polishedRodStroke_…

Computes rod-pump volumetric efficiency from actual rate and displacement.

Inputs: actualLiquidRate_bpd, pumpDisplacement_bpd.

Computes static injection-gas pressure gradient over a gas-lift annulus.

Inputs: surfaceInjectionPressure_psia, depth_ft, gasSpecificGravity, averageTem…

Computes casing pressure at depth for a static gas-lift gas column.

Inputs: surfaceCasingPressure_psia, depth_ft, gasSpecificGravity, averageTemper…

Computes IPO gas-lift valve opening pressure from dome and tubing pressure.

Inputs: domePressureAtDepth_psia, tubingPressureAtDepth_psia, portToBellowsArea…

Computes a straight-line gas-lift unloading gradient between two pressures.

Inputs: surfacePressure_psia, transferPressureAtDepth_psia, valveDepth_ft.

Computes required injected gas-liquid ratio from target and formation GLR.

Inputs: targetTotalGLR_scfPerSTB, formationGLR_scfPerSTB, liquidRate_STBPerD?.

Computes gas-lift compression horsepower with a polytropic ideal-gas form.

Inputs: injectionGasRate_MscfPerD, suctionPressure_psia, dischargePressure_psia…

Computes the line-source well function W(u) = -Ei(-u).

Inputs: u.

Computes radial and drainage-area dimensionless time in field units.

Inputs: kMd, tHours, phi, muCp, ctPerPsi, rwFt, rFt?, drainageAreaAcres?.

Computes semilog line-source dimensionless pressure for tD above about 100.

Inputs: tD.

Computes infinite-acting line-source pressure at radius and time.

Inputs: initialPressurePsi, qStbd, muCp, BoRbPerStb, kMd, hFt, phi, ctPerPsi, r…

Computes permeability and skin from MDH drawdown semilog slope.

Inputs: slopePsiPerCycle, qStbd, muCp, BoRbPerStb, hFt, p1hrPsi, pwf0Psi (=pi),…

Computes Horner buildup time ratio and its base-10 plotting coordinate.

Inputs: producingTimeHours, shutInTimeHours.

Computes permeability, skin, and p-star from a Horner buildup semilog line.

Inputs: slopePsiPerCycle, qStbd, muCp, BoRbPerStb, hFt, p1hrPsi, pwfAtShutInPsi…

Computes skin from the semilog 1-hour pressure; test buildup (default) or drawdown.

Inputs: p1hrPsi, referencePressurePsi, slopePsiPerCycle, kMd, phi, muCp, test?…

Computes pressure drop attributable to skin from semilog slope and skin.

Inputs: slopePsiPerCycle, skin.

Computes flow efficiency from total drawdown and skin pressure drop.

Inputs: averageReservoirPressurePsi, flowingBottomholePressurePsi, pressureDrop…

Computes line-source radius of investigation in field units.

Inputs: kMd, tHours, phi, muCp, ctPerPsi.

Computes wellbore storage coefficient from volume or unit-slope data.

Inputs: volumeUnderCompressionBbl? (bbl/ft), fluidDensityLbPerFt3?, qStbd?,…

Computes dimensionless wellbore storage coefficient.

Inputs: storageCoefficientBblPerPsi, phi, ctPerPsi, hFt, rwFt.

Estimates end of wellbore storage from the common semilog rule.

Inputs: storageCoefficientBblPerPsi, kMd, hFt, muCp, skin.

Looks up a Dietz shape factor for common closed drainage areas.

Inputs: shape.

Computes pseudosteady-state pressure drop using Dietz shape factor CA.

Inputs: initialPressurePsi, qStbd, muCp, BoRbPerStb, kMd, hFt, phi, ctPerPsi, r…

Computes Bourdet pressure derivative from time-pressure arrays.

Inputs: timesHours, pressuresPsi, smoothingLogCycles?.

Computes hydrostatic pressure gradient from fluid density.

Inputs: density_lbPerFt3.

Computes Darcy-Weisbach friction gradient with Chen explicit friction factor.

Inputs: density_lbPerFt3, velocity_ftPerS, pipeId_in, viscosity_cp, roughness_i…

Computes Reynolds number in field units for internal pipe flow.

Inputs: density_lbPerFt3, velocity_ftPerS, pipeId_in, viscosity_cp.

Computes liquid and gas superficial velocities from field rates.

Inputs: liquidRate_STBPerD, gasRate_Mscfd, pipeId_in, pressure_psia, temperatur…

Computes mixture superficial velocity as vsl plus vsg.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS.

Computes no-slip liquid holdup from superficial velocities.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS.

Computes static gas bottomhole pressure using average T and z.

Inputs: wellheadPressure_psia, trueVerticalDepth_ft, gasSpecificGravity, averag…

Computes flowing gas bottomhole pressure with gas friction in tubing.

Inputs: wellheadPressure_psia, measuredDepth_ft, trueVerticalDepth_ft?, gasSpec…

Classifies Beggs-Brill horizontal flow pattern from lambda and Froude number.

Inputs: noSlipLiquidHoldup_fraction, froudeNumber.

Computes Beggs-Brill liquid holdup with inclination correction.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS, pipeId…

Computes full Beggs-Brill pressure gradient with elevation, friction, acceleration.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS, pipeId…

Computes Hagedorn-Brown holdup using digitized-chart polynomial fits.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS, pipeId…

Computes Hagedorn-Brown pressure gradient with chart-fit holdup.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS, pipeId…

Computes Gray wet-gas vertical pressure gradient in closed form.

Inputs: superficialLiquidVelocity_ftPerS, superficialGasVelocity_ftPerS, pipeId…

Marches a pressure traverse down the well using Beggs-Brill or Gray.

Inputs: correlation, wellheadPressure_psia, measuredDepth_ft, trueVerticalDepth…

Wellbore trajectory from a deviation survey by minimum curvature: TVD, northing, easting, dogleg.

Inputs: stations [{md,inc,azi}] degrees, units 'ft'|'m'. Origin = 1st station.

Interpolate a wellbore survey at any measured depth on the minimum curvature arc.

Inputs: stations, md, units. Returns inc/azi/TVD/N/E at md.

Dogleg severity between two wellbore survey stations, per 100 ft or 30 m.

Inputs: md1,inc1,azi1,md2,inc2,azi2, units.

Vertical section projection of a wellbore survey onto a target azimuth plane.

Inputs: stations, vsAzimuth deg, units.

Closure distance and azimuth from surface to bottomhole for a deviation survey.

Inputs: stations, units.

Build and turn rates between survey stations of a wellbore trajectory.

Inputs: stations, units. Rates per 100 ft / 30 m.

Wellbore position uncertainty, ISCWSA MWD error model (Rev5.11 default or Rev4): sigma N/E/V.

Inputs: stations, bTotal (nT), dip, declination, units, errorModel rev4|rev5.

Anti-collision separation factor between two wells: ISCWSA pedal-curve, Rev5.11 default or Rev4.

Inputs: reference/offsetStations, bTotal, dip, declination, units, errorModel.

Build a 3D subsurface trajectory map payload from deviation surveys, for patchops_render.

wells [{stations, surfaceLat, surfaceLon, name?, color?}], units. Out: mapSpec.

Wellbore trajectory as GeoJSON for map rendering, from a survey and surface location.

First station anchored at surfaceLat/Lon. Depth = negative altitude.

Convert feet (ft) to meters (m). Factor: 1 ft = 0.3048 m. Ref: NIST.

Inputs: value.

Convert meters (m) to feet (ft). Factor: 1 m = 1/0.3048 ft. Ref: NIST.

Inputs: value.

Convert inches (in) to centimeters (cm). Factor: 1 in = 2.54 cm. Ref: NIST.

Inputs: value.

Convert centimeters (cm) to inches (in). Factor: 1 cm = 1/2.54 in. Ref: NIST.

Inputs: value.

Convert miles (mi) to kilometers (km). Factor: 1 mi = 1.609344 km. Ref: NIST.

Inputs: value.

Convert kilometers (km) to miles (mi). Factor: 1 km = 1/1.609344 mi. Ref: NIST.

Inputs: value.

Convert feet (ft) to inches (in). Factor: 1 ft = 12 in. Ref: NIST.

Inputs: value.

Convert inches (in) to feet (ft). Factor: 1 in = 1/12 ft. Ref: NIST.

Inputs: value.

Convert acres (acre) to square feet (ft2). Factor: 1 acre = 43560 ft2. Ref: NIST.

Inputs: value.

Convert square feet (ft2) to acres (acre). Factor: 1 ft2 = 1/43560 acre. Ref: NIST.

Inputs: value.

Convert acres (acre) to square meters (m2). Factor: 1 acre = 4046.8564224 m2. Ref: NIST.

Inputs: value.

Convert square meters (m2) to acres (acre). Factor: 1 m2 = 1/4046.8564224 acre. Ref: NIST.

Inputs: value.

Convert square feet (ft2) to square meters (m2). Factor: 1 ft2 = 0.09290304 m2. Ref: NIST.

Inputs: value.

Convert square meters (m2) to square feet (ft2). Factor: 1 m2 = 1/0.09290304 ft2. Ref: NIST.

Inputs: value.

Convert square miles (mi2) to acres (acre). Factor: 1 mi2 = 640 acre. Ref: NIST.

Inputs: value.

Convert acres (acre) to square miles (mi2). Factor: 1 acre = 1/640 mi2. Ref: NIST.

Inputs: value.

Convert barrels (bbl) to cubic feet (ft3). Factor: 1 bbl = 5.614583 ft3. Ref: API.

Inputs: value.

Convert cubic feet (ft3) to barrels (bbl). Factor: 1 ft3 = 1/5.614583 bbl. Ref: API.

Inputs: value.

Convert barrels (bbl) to gallons (gal). Factor: 1 bbl = 42 gal. Ref: API.

Inputs: value.

Convert gallons (gal) to barrels (bbl). Factor: 1 gal = 1/42 bbl. Ref: API.

Inputs: value.

Convert barrels (bbl) to cubic meters (m3). Factor: 1 bbl = 0.158987 m3. Ref: API.

Inputs: value.

Convert cubic meters (m3) to barrels (bbl). Factor: 1 m3 = 1/0.158987 bbl. Ref: API.

Inputs: value.

Convert cubic feet (ft3) to cubic meters (m3). Factor: 1 ft3 = 0.028316846592 m3. Ref: NIST.

Inputs: value.

Convert cubic meters (m3) to cubic feet (ft3). Factor: 1 m3 = 1/0.028316846592 ft3. Ref: NIST.

Inputs: value.

Convert thousand standard cubic feet (Mscf) to thousand cubic feet (Mcf). Factor: 1 Mscf = 1 Mcf.

Inputs: value.

Convert thousand cubic feet (Mcf) to thousand standard cubic feet (Mscf). Factor: 1 Mcf = 1 Mscf.

Inputs: value.

Convert million standard cubic feet (MMscf) to cubic meters (m3). Factor: 1 MMscf = 28316.846592 m3.

Inputs: value.

Convert cubic meters (m3) to million standard cubic feet (MMscf).

Inputs: value.

Convert pounds-mass (lbm) to kilograms (kg). Factor: 1 lbm = 0.45359237 kg. Ref: NIST.

Inputs: value.

Convert kilograms (kg) to pounds-mass (lbm). Factor: 1 kg = 1/0.45359237 lbm. Ref: NIST.

Inputs: value.

Convert pounds-force (lbf) to newtons (N). Factor: 1 lbf = 4.4482216152605 N. Ref: NIST.

Inputs: value.

Convert newtons (N) to pounds-force (lbf). Factor: 1 N = 1/4.4482216152605 lbf. Ref: NIST.

Inputs: value.

Convert short tons (short ton) to kilograms (kg). Factor: 1 short ton = 907.18474 kg. Ref: NIST.

Inputs: value.

Convert kilograms (kg) to short tons (short ton). Factor: 1 kg = 1/907.18474 short ton. Ref: NIST.

Inputs: value.

Convert pounds per square inch (psi) to kilopascals (kPa). Factor: 1 psi = 6.894757 kPa. Ref: NIST.

Inputs: value.

Convert kilopascals (kPa) to pounds per square inch (psi). Factor: 1 kPa = 1/6.894757 psi.

Inputs: value.

Convert pounds per square inch (psi) to bar (bar). Factor: 1 psi = 0.06894757 bar. Ref: NIST.

Inputs: value.

Convert bar (bar) to pounds per square inch (psi). Factor: 1 bar = 1/0.06894757 psi. Ref: NIST.

Inputs: value.

Convert pounds per square inch (psi) to atmospheres (atm). Factor: 1 psi = 0.0680459639 atm.

Inputs: value.

Convert atmospheres (atm) to pounds per square inch (psi). Factor: 1 atm = 1/0.0680459639 psi.

Inputs: value.

Convert pounds per square inch (psi) to pascals (Pa). Factor: 1 psi = 6894.757 Pa. Ref: NIST.

Inputs: value.

Convert pascals (Pa) to pounds per square inch (psi). Factor: 1 Pa = 1/6894.757 psi. Ref: NIST.

Inputs: value.

Convert pounds per square inch (psi) to megapascals (MPa). Factor: 1 psi = 0.006894757 MPa.

Inputs: value.

Convert megapascals (MPa) to pounds per square inch (psi). Factor: 1 MPa = 1/0.006894757 psi.

Inputs: value.

Convert pounds per square inch (psi) to kilograms-force per square centimeter (kgf/cm2).

Inputs: value.

Convert kilograms-force per square centimeter (kgf/cm2) to pounds per square inch (psi).

Inputs: value.

Convert pounds per square inch (psi) to inches of mercury (inHg). Factor: 1 psi = 2.03602 inHg.

Inputs: value.

Convert inches of mercury (inHg) to pounds per square inch (psi). Factor: 1 inHg = 1/2.03602 psi.

Inputs: value.

Convert pounds per square inch (psi) to feet of water column (ftH2O). Factor: 1 psi = 2.30666 ftH2O.

Inputs: value.

Convert feet of water column (ftH2O) to pounds per square inch (psi).

Inputs: value.

Convert pounds per cubic foot (lb/ft3) to kilograms per cubic meter (kg/m3).

Inputs: value.

Convert kilograms per cubic meter (kg/m3) to pounds per cubic foot (lb/ft3).

Inputs: value.

Convert API gravity (API) to specific gravity (SG). Factor: SG = 141.5/(131.5+API). Ref: API.

Inputs: value.

Convert specific gravity (SG) to API gravity (API). Factor: API = 141.5/SG - 131.5. Ref: API.

Inputs: value.

Convert specific gravity (SG) to pounds per gallon (lb/gal). Factor: 1 SG = 8.345404 lb/gal.

Inputs: value.

Convert pounds per gallon (lb/gal) to specific gravity (SG). Factor: 1 lb/gal = 1/8.345404 SG.

Inputs: value.

Convert pounds per cubic foot (lb/ft3) to pounds per gallon (lb/gal).

Inputs: value.

Convert pounds per gallon (lb/gal) to pounds per cubic foot (lb/ft3).

Inputs: value.

Convert mud weight in pounds per gallon (ppg) to pressure gradient in psi per foot (psi/ft).

Inputs: value.

Convert pressure gradient in psi per foot (psi/ft) to mud weight in pounds per gallon (ppg).

Inputs: value.

Convert degrees Fahrenheit (F) to degrees Celsius (C). Factor: C = (F - 32)*5/9. Ref: NIST.

Inputs: value.

Convert degrees Celsius (C) to degrees Fahrenheit (F). Factor: F = C*9/5 + 32. Ref: NIST.

Inputs: value.

Convert degrees Fahrenheit (F) to Kelvin (K). Factor: K = (F + 459.67)*5/9. Ref: NIST.

Inputs: value.

Convert Kelvin (K) to degrees Fahrenheit (F). Factor: F = K*9/5 - 459.67. Ref: NIST.

Inputs: value.

Convert degrees Celsius (C) to Kelvin (K). Factor: K = C + 273.15. Ref: NIST.

Inputs: value.

Convert Kelvin (K) to degrees Celsius (C). Factor: C = K - 273.15. Ref: NIST.

Inputs: value.

Convert degrees Fahrenheit (F) to degrees Rankine (R). Factor: R = F + 459.67. Ref: NIST.

Inputs: value.

Convert degrees Rankine (R) to degrees Fahrenheit (F). Factor: F = R - 459.67. Ref: NIST.

Inputs: value.

Convert degrees Celsius (C) to degrees Rankine (R). Factor: R = (C + 273.15)*9/5. Ref: NIST.

Inputs: value.

Convert degrees Rankine (R) to degrees Celsius (C). Factor: C = R*5/9 - 273.15. Ref: NIST.

Inputs: value.

Convert centipoise viscosity (cP) to pascal-second viscosity (Pa*s). Factor: 1 cP = 0.001 Pa*s.

Inputs: value.

Convert pascal-second viscosity (Pa*s) to centipoise viscosity (cP). Factor: 1 Pa*s = 1000 cP.

Inputs: value.

Convert centipoise viscosity (cP) to pounds per foot-second viscosity (lb/(ft*s)).

Inputs: value.

Convert pounds per foot-second viscosity (lb/(ft*s)) to centipoise viscosity (cP).

Inputs: value.

Convert millidarcys permeability (md) to square meters (m2). Factor: 1 md = 9.869233e-16 m2.

Inputs: value.

Convert square meters (m2) to millidarcys permeability (md). Factor: 1 m2 = 1/9.869233e-16 md.

Inputs: value.

Convert millidarcys permeability (md) to square micrometers (um2). Factor: 1 md = 0.0009869233 um2.

Inputs: value.

Convert square micrometers (um2) to millidarcys permeability (md).

Inputs: value.

Convert darcys permeability (darcy) to millidarcys permeability (md). Factor: 1 darcy = 1000 md.

Inputs: value.

Convert millidarcys permeability (md) to darcys permeability (darcy). Factor: 1 md = 1/1000 darcy.

Inputs: value.

Convert barrels per day (bbl/d) to cubic meters per day (m3/d). Factor: 1 bbl/d = 0.158987 m3/d.

Inputs: value.

Convert cubic meters per day (m3/d) to barrels per day (bbl/d). Factor: 1 m3/d = 1/0.158987 bbl/d.

Inputs: value.

Convert barrels per day (bbl/d) to gallons per minute (gal/min).

Inputs: value.

Convert gallons per minute (gal/min) to barrels per day (bbl/d).

Inputs: value.

Convert thousand standard cubic feet per day (Mscf/d) to cubic meters per day (m3/d).

Inputs: value.

Convert cubic meters per day (m3/d) to thousand standard cubic feet per day (Mscf/d).

Inputs: value.

Convert stock-tank barrels per day (STB/d) to barrels per day (bbl/d). Factor: 1 STB/d = 1 bbl/d.

Inputs: value.

Convert barrels per day (bbl/d) to stock-tank barrels per day (STB/d). Factor: 1 bbl/d = 1 STB/d.

Inputs: value.

Convert standard cubic feet per stock-tank barrel (scf/STB) to cubic meters per cubic meter (m3/m3).

Inputs: value.

Convert cubic meters per cubic meter (m3/m3) to standard cubic feet per stock-tank barrel (scf/STB).

Inputs: value.

Convert standard cubic feet per barrel (scf/bbl) to cubic meters per cubic meter (m3/m3).

Inputs: value.

Convert cubic meters per cubic meter (m3/m3) to standard cubic feet per barrel (scf/bbl).

Inputs: value.

Convert British thermal units (Btu) to kilojoules (kJ). Factor: 1 Btu = 1.05505585262 kJ. Ref: NIST.

Inputs: value.

Convert kilojoules (kJ) to British thermal units (Btu). Factor: 1 kJ = 1/1.05505585262 Btu.

Inputs: value.

Convert horsepower (hp) to kilowatts (kW). Factor: 1 hp = 0.745699871582 kW. Ref: NIST.

Inputs: value.

Convert kilowatts (kW) to horsepower (hp). Factor: 1 kW = 1/0.745699871582 hp. Ref: NIST.

Inputs: value.

Convert Btu per standard cubic foot (Btu/scf) to kilojoules per cubic meter (kJ/m3).

Inputs: value.

Convert kilojoules per cubic meter (kJ/m3) to Btu per standard cubic foot (Btu/scf).

Inputs: value.

Convert barrels (bbl) to metric tonnes using API gravity (tonnes by API). Factor: t=bbl*0.158987*SG.

Inputs: value, api.

Convert metric tonnes (tonnes) to barrels using API gravity (bbl by API).

Inputs: value, api.

Convert measured depth and angle (MD ft and angle) to true vertical depth (TVD ft).

Inputs: value, angleDeg.

Convert true vertical depth and angle (TVD ft and angle) to measured depth (MD ft).

Inputs: value, angleDeg.

Convert kilograms per cubic meter (kg/m3) to API gravity (API).

Inputs: value.

Convert pounds per cubic foot (lb/ft3) to API gravity (API).

Inputs: value.

Convert API gravity (API) to kilograms per cubic meter (kg/m3). Factor: kg/m3 = SG*1000. Ref: API.

Inputs: value.

Convert API gravity (API) to pounds per cubic foot (lb/ft3).

Inputs: value.

Lookup component critical properties. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

List component table keys. Ref: GPSA Engineering Data Book; Katz et al.

Compute apparent molecular weight. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: components, moleFractions.

Compute gas specific gravity relative to air. Ref: GPSA Engineering Data Book.

Inputs: apparentMW?, components?, moleFractions?.

Compute Kay pseudo-critical temperature and pressure. Ref: Katz et al.

Inputs: components, moleFractions.

Compute Sutton pseudo-criticals from gas gravity. Ref: Sutton 1985.

Inputs: gasGravity.

Compute pseudo-reduced pressure and temperature. Ref: Katz et al.

Inputs: P, T, Ppc, Tpc.

Correct sour-gas pseudo-critical properties. Ref: Wichert-Aziz 1972.

Inputs: Tpc, Ppc, yCO2, yH2S.

Convert gas gravity to molar mass. Ref: GPSA Engineering Data Book.

Inputs: gasGravity.

Compute ideal gas density in field units. Ref: GPSA Engineering Data Book.

Inputs: P, T, MW.

Convert component mole fractions to weight fractions. Ref: Katz et al.

Inputs: components, moleFractions.

Convert component weight fractions to mole fractions. Ref: Katz et al.

Inputs: components, weightFractions.

Compute Kay mixture critical temperature. Ref: Katz et al.

Inputs: components, moleFractions.

Compute Kay mixture pseudo-critical pressure. Ref: Katz et al.

Inputs: components, moleFractions.

Compute Standing-Katz pseudo-criticals from gas gravity. Ref: Katz et al.

Inputs: gasGravity, type.

Lookup component critical temperature. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

Lookup component critical pressure. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

Lookup component acentric factor. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

Lookup component molecular weight. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

Lookup component normal boiling point. Ref: GPSA Engineering Data Book; Katz et al.

Inputs: component.

Archie F, F=a/phi^m. Ref: Archie 1942.

Inputs: a, m, phi_fraction.

Archie Sw, Sw=((a*Rw)/(phi^m*Rt))^(1/n). Ref: Archie 1942.

Inputs: a, m, n, rw_ohm_m, phi_fraction, rt_ohm_m.

Archie RI, RI=Rt/Ro. Ref: Archie 1942.

Inputs: rt_ohm_m, ro_ohm_m.

Resistivity index from water saturation, RI=Sw^-n (Archie 1942).

Inputs: sw_fraction, n.

Archie Rt, Rt=(a*Rw)/(phi^m*Sw^n). Ref: Archie 1942.

Inputs: a, m, n, rw_ohm_m, phi_fraction, sw_fraction.

Archie phi, phi=((a*Rw)/(Rt*Sw^n))^(1/m). Ref: Archie 1942.

Inputs: a, m, n, rw_ohm_m, rt_ohm_m, sw_fraction.

Archie n, n=ln(aRw/(phi^m*Rt))/ln(Sw). Ref: Archie 1942.

Inputs: a, m, rw_ohm_m, phi_fraction, rt_ohm_m, sw_fraction.

Archie m, m=ln(aRw/(Rt*Sw^n))/ln(phi). Ref: Archie 1942.

Inputs: a, n, rw_ohm_m, phi_fraction, rt_ohm_m, sw_fraction.

Density porosity, phi=(rhoma-rhob)/(rhoma-rhofl). Ref: Schlumberger.

Inputs: rhoma_g_cm3, rhofl_g_cm3, rhob_g_cm3.

Density shale correction, phiE=phiD-Vsh*phiDsh. Ref: Schlumberger.

Inputs: rhoma_g_cm3, rhofl_g_cm3, rhob_g_cm3, rhosh_g_cm3, vsh_fraction.

Matrix density, rhoma=(rhob-phi*rhofl)/(1-phi). Ref: Schlumberger.

Inputs: rhob_g_cm3, rhofl_g_cm3, phi_fraction.

Neutron-density porosity, phi=sqrt((phiN^2+phiD^2)/2). Ref: Schlumberger.

Inputs: phi_neutron_fraction, phi_density_fraction.

Neutron shale correction, phiE=phiN-Vsh*phiNsh. Ref: Schlumberger.

Inputs: phi_neutron_fraction, vsh_fraction, phi_neutron_shale_fraction.

Sonic Wyllie porosity, phi=(dt-dtma)/(dtfl-dtma). Ref: Schlumberger.

Inputs: dt_us_ft, dtma_us_ft, dtfl_us_ft.

Sonic RHG porosity, 1/dt=(1-phi)^2/dtma+phi/dtfl. Ref: Schlumberger.

Inputs: dt_us_ft, dtma_us_ft, dtfl_us_ft.

Sonic porosity pair, phiW=(dt-dtma)/(dtfl-dtma). Ref: Schlumberger.

Inputs: dt_us_ft, dtma_us_ft, dtfl_us_ft.

Secondary porosity index, SPI=phiND-phiS. Ref: Schlumberger.

Inputs: phi_neutron_density_fraction, phi_sonic_fraction.

Total porosity, phiT=phiE+Vsh*phiSh. Ref: Schlumberger.

Inputs: phi_effective_fraction, vsh_fraction, phi_shale_fraction.

Effective porosity, phiE=phiT-Vsh*phiSh. Ref: Schlumberger.

Inputs: phi_total_fraction, vsh_fraction, phi_shale_fraction.

Gamma-ray index, IGR=(GR-GRmin)/(GRmax-GRmin). Ref: Asquith-Krygowski.

Inputs: gr_api, gr_min_api, gr_max_api.

Linear shale volume, Vsh=IGR. Ref: Asquith-Krygowski.

Inputs: igr_fraction.

Larionov Tertiary Vsh, Vsh=0.083*(2^(3.7*IGR)-1). Ref: Schlumberger.

Inputs: igr_fraction.

Larionov older Vsh, Vsh=0.33*(2^(2*IGR)-1). Ref: Schlumberger.

Inputs: igr_fraction.

Clavier shale volume, Vsh=1.7-sqrt(3.38-(IGR+0.7)^2). Ref: Schlumberger.

Inputs: igr_fraction.

Steiber shale volume, Vsh=IGR/(3-2*IGR). Ref: Schlumberger.

Inputs: igr_fraction.

Arps resistivity correction, R2=R1*(T1+6.77)/(T2+6.77). Ref: Arps.

Inputs: r1_ohm_m, t1_f, t2_f.

Rmf at formation temp, Rmf2=Rmf1*(T1+6.77)/(Tf+6.77). Ref: Arps.

Inputs: rmf1_ohm_m, measured_temp_f, formation_temp_f.

SP water resistivity, Rw=Rmf/10^(-SSP/K). Ref: Asquith-Krygowski.

Inputs: ssp_mv, rmf_ohm_m, formation_temp_f.

Static SP, SSP=-K*log10(Rmf/Rw). Ref: Asquith-Krygowski.

Inputs: rw_ohm_m, rmf_ohm_m, formation_temp_f.

Formation temperature, Tf=Ts+grad*depth/100. Ref: Asquith-Krygowski.

Inputs: surface_temp_f, gradient_f_per_100ft, tvd_ft.

Bulk volume water, BVW=phi*Sw. Ref: Schlumberger.

Inputs: phi_fraction, sw_fraction.

Flushed BVW, BVWxo=phi*Sxo. Ref: Schlumberger.

Inputs: phi_fraction, sxo_fraction.

Moveable hydrocarbons, BVHmov=phi*(Sxo-Sw). Ref: Schlumberger.

Inputs: phi_fraction, sw_fraction, sxo_fraction.

Hydrocarbon saturation, Sh=1-Sw. Ref: Schlumberger.

Inputs: sw_fraction.

Residual hydrocarbon saturation, Shr=1-Sxo. Ref: Schlumberger.

Inputs: sxo_fraction.

Water-filled porosity, WFP=phi*Sw. Ref: Schlumberger.

Inputs: phi_fraction, sw_fraction.

Simandoux Sw, Ct=A*Sw^n+B*Sw. Ref: Schlumberger.

Inputs: a, m, n, rw_ohm_m, phi_fraction, rt_ohm_m, vsh_fraction, rsh_ohm_m.

Indonesia Sw, 1/sqrt(Rt)=A*Sw^(n/2). Ref: Poupon-Leveaux.

Inputs: a, m, n, rw_ohm_m, phi_fraction, rt_ohm_m, vsh_fraction, rsh_ohm_m.

Waxman-Smits Sw, Ct=A(Cw*Sw^n+BQv*Sw^(n-1)). Ref: Waxman-Smits.

Inputs: a, m, n, rw_ohm_m, phi_fraction, rt_ohm_m, bqv_s_per_m.

Timur permeability, k=8581*phi^4.4/Swirr^2. Ref: Asquith-Krygowski.

Inputs: phi_fraction, swirr_fraction.

Coates-Dumanoir k, k=(C*phi^2*((1-Swirr)/Swirr))^2. Ref: Schlumberger.

Inputs: phi_fraction, swirr_fraction, c_factor?.

Wyllie-Rose permeability, k=(C*phi^3/Swirr)^2. Ref: Asquith-Krygowski.

Inputs: phi_fraction, swirr_fraction, coefficient_md? (C in sqrt(md), 250 oil).

Morris-Biggs permeability, k=C*phi^6/Swirr^2. Ref: Asquith-Krygowski.

Inputs: phi_fraction, swirr_fraction, fluid?.

Net pay flag, pay=phi>=cutoff && Sw<=cutoff && Vsh<=cutoff. Ref: Schlumberger.

Inputs: phi_fraction, sw_fraction, vsh_fraction, phi_cutoff_fraction, sw_cutoff…

Net-to-gross, NTG=net/gross. Ref: Schlumberger.

Inputs: net_pay_ft, gross_thickness_ft.

Hydrocarbon pore volume, HCPV=phi*(1-Sw)*h*area. Ref: Schlumberger.

Inputs: phi_fraction, sw_fraction, thickness_ft, area_acres.

Pickett slope, m=-dlog(Rt)/dlog(phi). Ref: Archie 1942.

Inputs: phi1_fraction, rt1_ohm_m, phi2_fraction, rt2_ohm_m.

Pickett Sw, Sw=((a*Rw)/(phi^m*Rt))^(1/n). Ref: Archie 1942.

Inputs: a, m, n, rw_ohm_m, phi_fraction, rt_ohm_m.

Apparent water resistivity, Rwa=phi^m*Rt/a. Ref: Archie 1942.

Inputs: a, m, phi_fraction, rt_ohm_m.

Flushed-zone Sw, Sxo=((a*Rmf)/(phi^m*Rxo))^(1/n). Ref: Archie 1942.

Inputs: a, m, n, rmf_ohm_m, phi_fraction, rxo_ohm_m.

Hydrostatic pressure psi: P=0.052*MW*TVD. Ref: Bourgoyne/API13D.

Inputs: mudWeight_ppg, tvd_ft.

Mud weight ppg: MW=gradient/0.052. Ref: Bourgoyne/API13D.

Inputs: pressureGradient_psi_per_ft.

Pressure gradient psi/ft: G=0.052*MW. Ref: Bourgoyne/API13D.

Inputs: mudWeight_ppg.

Equivalent mud weight ppg: EMW=P/(0.052*TVD). Ref: Bourgoyne/API13D.

Inputs: pressure_psi, tvd_ft.

Equivalent circulating density ppg: ECD=MW+dP/(0.052*TVD). Ref: API13D.

Inputs: mudWeight_ppg, annularPressureLoss_psi, tvd_ft.

Annular velocity ft/min: AV=24.51*q/(Dh^2-Dp^2). Ref: API13D.

Inputs: flowRate_gpm, holeDiameter_in, pipeOuterDiameter_in.

Pipe velocity ft/min: V=24.51*q/ID^2. Ref: API13D.

Inputs: flowRate_gpm, pipeInnerDiameter_in.

Critical velocity ft/s: Vc=Re*mu/(928*MW*D). Ref: API13D.

Inputs: mudWeight_ppg, viscosity_cp, hydraulicDiameter_in, criticalReynoldsNumb…

Triplex pump output bbl/stk: O=0.000243*D^2*S*E. Ref: Bourgoyne.

Inputs: linerDiameter_in, strokeLength_in, pumpEfficiency_fraction, pumpSpeed_s…

Duplex pump output bbl/stk: O=0.000162*S*(2D^2-r^2)*E. Ref: Bourgoyne.

Inputs: linerDiameter_in, rodDiameter_in, strokeLength_in, pumpEfficiency_fract…

Pump pressure psi: P=HHP*1714/q. Ref: Bourgoyne/API13D.

Inputs: hydraulicHorsepower_hp, flowRate_gpm.

Bottoms-up strokes: strokes=annularVolume/pumpOutput. Ref: Bourgoyne/API13D.

Inputs: holeDiameter_in, pipeOuterDiameter_in, measuredDepth_ft, pumpOutput_bbl…

Annular capacity bbl/ft: C=(Dh^2-Dp^2)/1029.4. Ref: Bourgoyne.

Inputs: holeDiameter_in, pipeOuterDiameter_in.

Pipe capacity bbl/ft: C=ID^2/1029.4. Ref: Bourgoyne.

Inputs: pipeInnerDiameter_in.

Annular volume bbl: V=L*(Dh^2-Dp^2)/1029.4. Ref: Bourgoyne.

Inputs: holeDiameter_in, pipeOuterDiameter_in, length_ft.

Pipe displacement bbl: V=L*(OD^2-ID^2)/1029.4. Ref: Bourgoyne.

Inputs: pipeOuterDiameter_in, pipeInnerDiameter_in, length_ft.

Hole volume bbl: V=L*Dh^2/1029.4. Ref: Bourgoyne.

Inputs: holeDiameter_in, length_ft.

Lag time min: t=annularVolume/(q/42). Ref: Bourgoyne/API13D.

Inputs: holeDiameter_in, pipeOuterDiameter_in, measuredDepth_ft, flowRate_gpm.

Bit nozzle TFA in2: A=sum(pi/4*(n/32)^2). Ref: Bourgoyne/API13D.

Inputs: nozzleDiameters_32nds.

Jet velocity ft/s: Vj=0.32086*q/TFA. Ref: Bourgoyne/API13D.

Inputs: flowRate_gpm, totalFlowArea_in2.

Bit dP psi: dP=156.5*MW*q^2/(sum d32^2)^2. Ref: Bourgoyne/API13D.

Inputs: mudWeight_ppg, flowRate_gpm, totalFlowArea_in2.

Hydraulic horsepower hp: HHP=q*dP/1714. Ref: Bourgoyne/API13D.

Inputs: flowRate_gpm, pressureDrop_psi.

Bit area in2: A=pi*D^2/4. Ref: Bourgoyne/API13D.

Inputs: bitDiameter_in.

HSI hp/in2: HSI=(q*dP/1714)/(pi*Db^2/4). Ref: Bourgoyne/API13D.

Inputs: flowRate_gpm, bitPressureDrop_psi, bitDiameter_in.

Jet impact force lbf: JIF=0.01823*q*sqrt(MW*dP). Ref: Bourgoyne/API13D.

Inputs: flowRate_gpm, mudWeight_ppg, bitPressureDrop_psi.

Bit pressure fraction: f=dPbit/Ppump. Ref: Bourgoyne/API13D.

Inputs: bitPressureDrop_psi, pumpPressure_psi.

Flow exponent m=ln(dP2/dP1)/ln(q2/q1); optimum bit share m/(m+1) HHP, m/(m+2) JIF.

pressureDrop1/2_psi = parasitic (non-bit) losses at flowRate1/2_gpm.

Plastic viscosity cp: PV=theta600-theta300. Ref: API13D.

Inputs: theta600, theta300.

Yield point lbf/100ft2: YP=theta300-PV. Ref: API13D.

Inputs: theta300, plasticViscosity_cp.

Apparent viscosity cp: AV=theta600/2. Ref: API13D.

Inputs: theta600.

Power-law n: n=3.32*log10(theta600/theta300). Ref: API13D.

Inputs: theta600, theta300.

Power-law K in lbf*s^n/100ft2 = 1.0672*theta300/511^n (5.11 dyn/cm2/deg). API13D.

Inputs: theta600, theta300. Also returns Kp dyn*s^n/cm2 and dial-unit K.

Gel strength lbf/100ft2: G=theta3 after static time. Ref: API13D.

Inputs: theta3, staticTime_min.

Pipe Reynolds: Re=928*MW*V*D/mu_eff. Ref: Bourgoyne/API13D.

Inputs: flowRate_gpm, pipeInnerDiameter_in, mudWeight_ppg, rheologyModel?, plas…

Cutting slip ft/s: Vs=sqrt(4*g*d*(rhos-rhom)/(3*Cd*rhom)). Ref: API13D.

Inputs: cuttingDiameter_in, cuttingsDensity_ppg, mudWeight_ppg, fluidViscosity_…

Cuttings carrying fraction: C=max(0,(AV-Vs)/AV). Ref: Bourgoyne/API13D.

Inputs: annularVelocity_ft_min, slipVelocity_ft_min.

Kill mud weight ppg: KMW=MW+SIDPP/(0.052*TVD). Ref: Bourgoyne.

Inputs: currentMudWeight_ppg, shutInDrillPipePressure_psi, tvd_ft.

MAASP psi: MAASP=(FG/0.052-MW)*0.052*TVDshoe. Ref: Bourgoyne.

Inputs: fractureGradient_psi_per_ft, currentMudWeight_ppg, shoeTVD_ft.

Kick tolerance ppg: KT=FG/0.052-MW-margin. Ref: Bourgoyne.

Inputs: fractureGradient_psi_per_ft, mudWeight_ppg, shoeTVD_ft, safetyMargin_pp…

Formation pressure psi: Pf=0.052*MW*TVD+SIDPP. Ref: Bourgoyne.

Inputs: mudWeight_ppg, tvd_ft, shutInDrillPipePressure_psi.

Calculate OOIP; OOIP=7758*A*h*phi*(1-Sw)/Boi. Ref: SPE PRMS.

Inputs: area_acres, netPay_ft, porosity_fraction, waterSaturation_fraction, oil…

Calculate OGIP; OGIP=43560*A*h*phi*(1-Sw)/Bgi. Ref: SPE PRMS.

Inputs: area_acres, netPay_ft, porosity_fraction, waterSaturation_fraction, gas…

Calculate recoverable oil; R=OOIP*RF. Ref: SPE PRMS.

Inputs: originalOilInPlace_STB, recoveryFactor_fraction.

Calculate recovery factor; RF=recoverable/original. Ref: SPE PRMS.

Inputs: recoverableVolume_STB, originalVolume_STB.

Calculate decline reserves; R=EUR-Np using Arps qi,Di,b,qab. Ref: Arps 1945.

Inputs: initialRate_STBPerDay, nominalDeclineRate_perDay, declineExponent, aban…

Calculate drainage volume; V=A*h. Ref: SPE PRMS.

Inputs: drainageArea_acres, netPay_ft.

Calculate net rock volume; NRV=A*Hgross*NTG. Ref: SPE PRMS.

Inputs: area_acres, grossThickness_ft, netToGross_fraction.

Calculate present value; PV=FV/(1+i)^n. Ref: standard DCF.

Inputs: futureValue_USD, discountRate_fraction, periods.

Calculate future value; FV=PV*(1+i)^n. Ref: standard DCF.

Inputs: presentValue_USD, discountRate_fraction, periods.

Calculate NPV; NPV=sum(CFt/(1+i)^t). Ref: standard DCF.

Inputs: cashflows_USD[] (CF0 at t=0, end-of-period), discountRate_fraction.

Revenue-statement rollups: tie-outs, tax/deduction categories, statement-vs-state deltas.

Flat statement.json keys: statement, properties. Unknown labels = deductions.

Calculate discount factor; DF=1/(1+i)^n. Ref: standard DCF.

Inputs: discountRate_fraction, periods.

Calculate PV of annuity; PV=P*(1-(1+i)^-n)/i. Ref: standard DCF.

Inputs: payment_USD, discountRate_fraction, periods.

Calculate IRR; sum(CFt/(1+r)^t)=0. Ref: standard DCF.

Inputs: cashflows_USD[] (CF0 at t=0), guess_fraction?, tolerance?.

Calculate payback period; cumulative CF reaches zero. Ref: standard DCF.

Inputs: cashflows_USD[] (CF0 at t=0, end-of-period). Periods, interpolated.

Calculate discounted payback; cum discounted CF reaches zero. Ref: standard DCF.

Inputs: cashflows_USD[] (CF0 at t=0, end-of-period), discountRate_fraction.

Calculate profitability index; PI=PV future CF/investment. Ref: standard DCF.

Inputs: cashflows_USD[], discountRate_fraction, initialInvestment_USD?.

Calculate CAGR; g=(ending/beginning)^(1/n)-1. Ref: standard DCF.

Inputs: beginningValue_USD, endingValue_USD, periods.

Calculate gross revenue; GR=q*price. Ref: standard DCF.

Inputs: salesRate_bblPerDay, price_USDPerBbl.

Calculate NRI; NRI=WI*(1-royalty). Ref: standard DCF.

Inputs: workingInterest_fraction, royalty_fraction.

Calculate WI revenue; WIR=grossRevenue*WI. Ref: standard DCF.

Inputs: grossRevenue_USD, workingInterest_fraction.

Calculate royalty value; royalty=grossRevenue*royaltyRate. Ref: standard DCF.

Inputs: grossRevenue_USD, royalty_fraction.

Calculate net revenue; NR=grossRevenue*NRI. Ref: standard DCF.

Inputs: grossRevenue_USD, netRevenueInterest_fraction.

Calculate severance tax; tax=taxableRevenue*taxRate. Ref: standard DCF.

Inputs: taxableRevenue_USD, taxRate_fraction.

Calculate operating cash flow; OCF=NR-opex-tax. Ref: standard DCF.

Inputs: netRevenue_USD, operatingExpense_USD, tax_USD.

Calculate net cash flow; NCF=rev-opex-capex-tax. Ref: standard DCF.

Inputs: revenue_USD, operatingExpense_USD, capitalExpense_USD, tax_USD.

Calculate breakeven price; P=cost/(volume*NRI). Ref: standard DCF.

Inputs: totalCost_USD, salesVolume_bbl, netRevenueInterest_fraction.

Calculate breakeven volume; V=cost/(price*NRI). Ref: standard DCF.

Inputs: totalCost_USD, price_USDPerBbl, netRevenueInterest_fraction.

Calculate unit technical cost; UTC=(capex+opex+abex)/volume. Ref: SPE PRMS.

Inputs: capitalCost_USD, operatingCost_USD, abandonmentCost_USD?, recoverableVo…

Calculate ROI; ROI=netProfit/investment. Ref: standard DCF.

Inputs: netProfit_USD, investment_USD.

Calculate capital efficiency; CE=NPV/capex. Ref: standard DCF.

Inputs: npv_USD, capex_USD.

Calculate F&D cost; FDC=cost/reservesAdded. Ref: SPE PRMS.

Inputs: findingDevelopmentCost_USD, reservesAdded_STB.

Calculate economic limit rate; q=opex/(price*NRI*conv). Ref: standard DCF.

Inputs: operatingExpense_USDPerDay, price_USDPerBbl, netRevenueInterest_fractio…

Integrate density to OBG; OBG=sum(rho/144 dz)/sum(dz); Ref: Zoback.

Convert OBG to overburden stress; Sv=OBG*z; Ref: Zoback.

Integrate density log to vertical stress; Sv=sum(rho/144 dz); Ref: Zoback.

Eaton resistivity PP; PPg=OBG-(OBG-Pn)(Robs/Rn)^1.2; Ref: Eaton 1975.

Eaton sonic PP; PPg=OBG-(OBG-Pn)(DTn/DTo)^3; Ref: Eaton 1975.

Bowers PP from velocity; Pp=Sv-((Vp-V0)/A)^(1/B); Ref: Bowers 1995.

Normal hydrostatic PP; Pn=rho_fluid*z/144; Ref: Zoback.

Eaton fracture gradient; FG=nu/(1-nu)(OBG-PP)+PP; Ref: Eaton 1975.

Matthews-Kelly FG; FG=Ki(OBG-PP)+PP; Ref: Matthews-Kelly 1967.

Hubbert-Willis FG; FG=(OBG-PP)/3+PP; Ref: Hubbert-Willis 1957.

Daines fracture gradient; FG=nu/(1-nu)(OBG-aPP)+aPP+T; Ref: Daines.

Leak-off pressure from FG; P=FG*z; Ref: Zoback.

Terzaghi effective stress; sigma_eff=sigma-alpha Pp; Ref: Zoback.

Biot coefficient; alpha=1-Kdry/Kgrain; Ref: Zoback.

Convert sonic slowness to velocity; V=1e6/DT; Ref: log unit definition.

Dynamic Young modulus; E=2G(1+nu); Ref: Zoback log mechanics.

Dynamic Poisson ratio; nu=(R^2-2)/(2(R^2-1)); Ref: Zoback.

Dynamic shear modulus; G=C rho Vs^2; Ref: Zoback log mechanics.

Dynamic bulk modulus; K=C rho(Vp^2-4Vs^2/3); Ref: Zoback.

Compressibility from modulus; c=1/M; Ref: Zoback.

Velocity ratio; R=Vp/Vs; Ref: sonic log unit definition.

P-wave modulus; M=C rho Vp^2; Ref: Zoback log mechanics.

Static modulus correlation; Est=a Edyn+b; Ref: Zoback empirical.

Empirical UCS from sonic; UCS=f(Vp or DT); Ref: Horsrud/McNally/Freyburg.

Friction angle from UCS; phi=a+b log10(UCS/1000); Ref: Zoback empirical.

Mohr-Coulomb shear strength; tau=c+sigma_n tan(phi); Ref: Zoback.

Principal failure stress; sigma1=UCS+q sigma3; Ref: Zoback.

Minimum horizontal stress; Sh=nu/(1-nu)(Sv-aPp)+aPp+T; Ref: Zoback.

Breakdown pressure; Pb=3Shmin-SHmax-aPp+T0; Ref: Hubbert-Willis.

Collapse pressure; Pw=(3SH-Sh-UCS+aPp(q-1))/(1+q); Ref: Zoback.

Poroelastic horizontal stresses; Sh=base+E strain/(1-nu^2); Ref: Zoback.

Stress polygon bounds; S1e/S3e<=Q(mu); Ref: Zoback Reservoir Geomechanics.

Barlow burst pressure, Pb = 2*Yp*t*f/D. Ref API 5C3.

Inputs: od_in, t_in, Yp_psi, wallFactor?.

Internal yield pressure, Piy = 2*Yp*t*f/D. Ref API 5C3.

Inputs: od_in, t_in, Yp_psi, wallFactor?.

Burst safety factor, SF = Pb/Papplied. Ref Bourgoyne/API 5C3.

Inputs: burstPressure_psi, appliedPressure_psi.

Yield collapse pressure, Pyp = 2*Yp*(D/t-1)/(D/t)^2. Ref API 5C3.

Inputs: od_in, t_in, Yp_psi.

Collapse selector, Pc = API 5C3 four-regime D/t model. Ref API 5C3.

Inputs: od_in, t_in, Yp_psi.

Collapse safety factor, SF = Pc/Papplied. Ref Bourgoyne/API 5C3.

Inputs: collapsePressure_psi, appliedPressure_psi.

Pipe body yield strength, T = Yp*A. Ref API 5C3/Bourgoyne.

Inputs: od_in, id_in, Yp_psi.

Approx joint strength, Tj = efficiency*Yp*A. Ref API 5C2.

Inputs: od_in, id_in, Yp_psi, jointEfficiency?.

Tension safety factor, SF = Trating/Fapplied. Ref Bourgoyne.

Inputs: tensileRating_lbf, appliedLoad_lbf.

Axial stress from load, Sa = F/A. Ref Bourgoyne/API 5C3.

Inputs: load_lbf, area_in2.

Pipe steel area, A = pi/4*(OD^2-ID^2). Ref Bourgoyne.

Inputs: od_in, id_in.

Pipe air weight, W = A/144*rhoSteel. Ref Bourgoyne.

Inputs: od_in, id_in.

Buoyant pipe weight, Wb = Wair*(1-MW/65.4). Ref Bourgoyne.

Inputs: weight_lb_per_ft, mudWeight_ppg.

Buoyancy factor, BF = 1-MW/65.4. Ref Bourgoyne.

Inputs: mudWeight_ppg.

Air string weight, W = w*L. Ref Bourgoyne.

Inputs: weight_lb_per_ft, length_ft.

Hook load, H = w*L*(1-MW/65.4)+overpull. Ref Bourgoyne.

Inputs: weight_lb_per_ft, length_ft, mudWeight_ppg, overpull_lbf?.

Pipe capacity, C = pi/4*ID^2*12/9702. Ref Bourgoyne.

Inputs: id_in.

Pipe displacement, V = pi/4*(OD^2-ID^2)*12. Ref Bourgoyne.

Inputs: od_in, id_in.

Annular capacity, C = pi/4*(outerID^2-innerOD^2)*12/9702. Ref Bourgoyne.

Inputs: outerId_in, innerOd_in.

Internal volume, V = capacity*L. Ref Bourgoyne.

Inputs: id_in, length_ft.

Hooke stretch, e = F*L/(A*E). Ref Bourgoyne.

Inputs: load_lbf, length_ft, area_in2, E_psi?.

Stretch due to weight, e = w*BF*L*(12L)/(2AE). Ref Bourgoyne.

Inputs: weight_lb_per_ft, length_ft, area_in2, buoyancyFactor?, E_psi?.

Thermal elongation, dL = alpha*dT*L. Ref Bourgoyne.

Inputs: length_ft, temperatureChange_F, coefficient_per_F?.

Ballooning stretch, e = -2*nu*L*(dPi*Ai-dPo*Ao)/(E*As). Ref Bourgoyne.

Inputs: od_in, id_in, length_ft, internalPressureChange_psi, externalPressureCh…

Drift diameter, Ddrift = ID-allowance. Ref API 5C2.

Inputs: id_in, driftAllowance_in?.

Approx makeup torque, T = K*F*D/12. Ref API 5C2.

Inputs: axialPreload_lbf, diameter_in, torqueFactor?.

Von Mises triaxial stress, seq = sqrt(J2 form). Ref API 5C3.

Inputs: axialStress_psi, hoopStress_psi, radialStress_psi.

Biaxial collapse derating, Ypa = Yp*(sqrt(1-.75*r^2)-.5*r). Ref API 5C3.

Inputs: Yp_psi, axialStress_psi, internalPressure_psi?.

Minimum yield from OCTG grade lookup, Yp = table[grade]. Ref API 5CT/5C3.

Inputs: grade.