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89 published calculators available for analysis.

Production EngineeringWell Performance

Haaland Darcy Friction Factor

fD=[−1.8log⁡10A]−2A=(ε/D3.7)1.11+6.9Re\begin{aligned}f_D&=[-1.8\log_{10}A]^{-2}\\A&=\left(\frac{\varepsilon/D}{3.7}\right)^{1.11}+\frac{6.9}{\mathrm{Re}}\end{aligned}
Open analysis
Phase Behavior and ThermodynamicsGas Properties

Papay Gas Z-Factor Correlation

z=1−3.53Ppr100.9813Tpr+0.274Ppr2100.8157Tprz=1-\frac{3.53P_{pr}}{10^{0.9813T_{pr}}}+\frac{0.274P_{pr}^2}{10^{0.8157T_{pr}}}
Open analysis
Phase Behavior and ThermodynamicsGas Properties

Real Gas Density

ρg=PMgzRT\rho_g=\frac{P M_g}{zRT}
Open analysis
Phase Behavior and ThermodynamicsGas Properties

Real Gas Isothermal Compressibility with Z-Factor Derivative

cg=1P−1z(dzdP)Tc_g=\frac{1}{P}-\frac{1}{z}\left(\frac{dz}{dP}\right)_T
Open analysis
Phase Behavior and ThermodynamicsGas Properties

Real Gas Pseudopressure Difference for Constant Mu-Z

Δm=p22−p12μgz\Delta m=\frac{p_2^2-p_1^2}{\mu_g z}
Open analysis
PetrophysicsRock Properties

Sonic Porosity Raymer-Hunt-Gardner Method

Φsonic=CRHGΔt−ΔtmaΔt\Phi_{sonic}=C_{RHG}\frac{\Delta t-\Delta t_{ma}}{\Delta t}
Open analysis
PetrophysicsRock Properties

Gassmann Saturated Rock Bulk Modulus

Ksat=Kd+αB2ϕ/Kf+(αB−ϕ)/KsαB=1−Kd/Ks\begin{aligned}K_{\mathrm{sat}}&=K_d+\frac{\alpha_B^2}{\phi/K_f+(\alpha_B-\phi)/K_s}\\\alpha_B&=1-K_d/K_s\end{aligned}
Open analysis
PetrophysicsRock Properties

Brooks-Corey Drainage Capillary Pressure

Pc=PeSe−1/λ,0<Se≤1P_c=P_e S_e^{-1/\lambda},\quad 0<S_e\leq1
Open analysis
PetrophysicsRock Properties

van Genuchten Capillary Pressure

Pc=P0(Se−1/m−1)1−mn=1/(1−m)\begin{aligned}P_c&=P_0(S_e^{-1/m}-1)^{1-m}\\n&=1/(1-m)\end{aligned}
Open analysis
PetrophysicsResistivity Logs

Archie Water Saturation from Resistivity Logs

Sw=[(aϕm)(RwRt)]1/nS_w = \left[\left(\frac{a}{\phi^m}\right)\left(\frac{R_w}{R_t}\right)\right]^{1/n}
Open analysis
PetrophysicsResistivity Logs

Indonesian Water Saturation from Shaly Sand Logs

Sw=[1/RtVsh1−0.5VshRsh+ϕemaRw]2/nS_w=\left[\frac{\sqrt{1/R_t}}{\frac{V_{sh}^{1-0.5V_{sh}}}{\sqrt{R_{sh}}}+\sqrt{\frac{\phi_e^m}{aR_w}}}\right]^{2/n}
Open analysis
Production EngineeringHydraulic Fracturing

Carter Leakoff Volume for Hydraulic Fracturing

VL=AL(2CLt+Sp)V_L=A_L\left(2C_L\sqrt{t}+S_p\right)
Open analysis
Production EngineeringHydraulic Fracturing

Treatment Fracture Gradient - Hydraulic Fracturing

Gf=Pinj+ΔPh−ΔPf−ΔPpDG_f=\frac{P_{inj}+\Delta P_h-\Delta P_f-\Delta P_p}{D}
Open analysis
Drilling EngineeringDrilling Hydraulics

Annular Velocity from Pump Output

AV=24.5QDh2−Dp2AV = \frac{24.5Q}{D_h^2 - D_p^2}
Open analysis
Drilling EngineeringDrilling Hydraulics

Equivalent Circulating Density

ECD=MW+ΔPa0.052TVDECD = MW + \frac{\Delta P_a}{0.052TVD}
Open analysis
Drilling EngineeringDrilling Hydraulics

Maximum Drilling Rate for Larger Holes

MDR=67(MWo−MWi)qcDh2MDR = \frac{67(MW_o - MW_i)q_c}{D_h^2}
Open analysis
Drilling EngineeringDrilling Hydraulics

Velocity of Fluid in Annulus

va=Q2.448(Do2−Dp2)v_a = \frac{Q}{2.448(D_o^2-D_p^2)}
Open analysis
Drilling EngineeringDrilling Hydraulics

Annular Volume Capacity of Pipe

Va=0.7854(Dh2−Do2)L808.5V_a=\frac{0.7854(D_h^2-D_o^2)L}{808.5}
Open analysis
Drilling EngineeringDrilling Hydraulics

Herschel-Bulkley Drilling Fluid Shear Stress

τ=τy+Kγ˙n\tau=\tau_y+K\dot\gamma^n
Open analysis
Reservoir EngineeringReserves and Recovery

Stretched Exponential Decline Rate

q(t)=q^iexp⁡[−(tτ)n]q(t)=\hat q_i\exp\left[-\left(\frac{t}{\tau}\right)^n\right]
Open analysis
Reservoir EngineeringReserves and Recovery

Power-Law Exponential Decline Rate

q(t)=q^iexp⁡[−D∞t−D^itn]q(t)=\hat q_i\exp[-D_\infty t-\hat D_i t^n]
Open analysis
Reservoir EngineeringReserves and Recovery

Modified Hyperbolic Decline Rate

q(t)=qi(1+bDith)−1/b×e−Dt(t−th)th=min⁡(t,ts)ts=Di−DtbDiDt\begin{aligned}q(t)&=q_i(1+bD_it_h)^{-1/b}\\&\quad\times e^{-D_t(t-t_h)}\\t_h&=\min(t,t_s)\\t_s&=\frac{D_i-D_t}{bD_iD_t}\end{aligned}
Open analysis
Reservoir EngineeringReserves and Recovery

Logistic Growth Cumulative Oil Production

Np(t)=Ktnt1/2 n+tnN_p(t)=\frac{Kt^n}{t_{1/2}^{\,n}+t^n}
Open analysis
Reservoir EngineeringReserves and Recovery

Logistic Growth Oil Production Rate

q(t)=Knt1/2 ntn−1(t1/2 n+tn)2q(t)=\frac{Knt_{1/2}^{\,n}t^{n-1}}{(t_{1/2}^{\,n}+t^n)^2}
Open analysis