Code of Federal Regulations Title 40. Protection of Environment § 40.60.5432a How do I determine whether a well is a low pressure well using the low pressure well equation?

(1) P_L is the pressure of flowback fluid immediately before it enters the flow line, expressed in pounds force per square inch (psia), and is to be calculated using the equation above;

(2) P_R is the pressure of the reservoir containing oil, gas, and water at the well site, expressed in psia;

(3) Lis the true vertical depth of the well, expressed in feet (ft);

(4) q_o is the flow rate of oil in the well, expressed in cubic feet/second (cu ft/sec);

(5) q_g is the flow rate of gas in the well, expressed in cu ft/sec;

(6) q_w is the flow rate of water in the well, expressed in cu ft/sec;

(7) ρ_o is the density of oil in the well, expressed in pounds mass per cubic feet (lbm/cu ft).

(1) Determine the value of the bottom hole pressure, P_BH (psia), based on available information at the well site, or by calculating it using the reservoir pressure, P_R (psia), in the following equation:

(2) Determine the value of the bottom hole temperature, T_BH (F), based on available information at the well site, or by calculating it using the true vertical depth of the well, L (ft), in the following equation:

T_BH (F) = (0.014 x L) + 79.081

(3) Calculate the value of the applicable natural gas specific gravity that would result from a separator pressure of 100 psig, γ_gs, using the following equation with:  Separator at standard conditions (pressure, p = 14.7 (psia), temperature, T = 60 (F));  the oil API gravity at the well site, γ₀;  and the gas specific gravity at the separator under standard conditions, γ_gp = 0.75:

(4) Calculate the value of the applicable dissolved GOR, Rs (scf/STBO), using the following equation with:  The bottom hole pressure, P_BH (psia), determined in (b)(1) of this section;  the bottom hole temperature, T_BH (F), determined in (b)(2) of this section;  the gas gravity at separator pressure of 100 psig, γ_gs, calculated in (b)(3) of this section;  the oil API gravity, γ_o, at the well site;  and the constants, C1, C2, and C3, found in Table A:

(5) Calculate the value of the oil formation volume factor, Bo (bbl/STBO), using the following equation with:  the bottom hole temperature, T_BH (F), determined in paragraph (b)(2) of this section;  the gas gravity at separator pressure of 100 psig, γ_gs, calculated in paragraph (b)(3) of this section;  the dissolved GOR, Rs (scf/STBO), calculated in paragraph (b)(4) of this section;  the oil API gravity, γ_o, at the well site;  and the constants, C1, C2, and C3, found in Table B:

(10) Calculate the critical pressure, P_c (psia), and critical temperature, T_c (R), using the equations below with:  Gas gravity at standard conditions (pressure, P = 14.7 (psia), temperature, T = 60 (F)), γ = 0.75;  and where the mole fractions of nitrogen, carbon dioxide and hydrogen sulfide in the gas are X_N2 = 0.168225, X_CO2 = 0.013163, and X_H2S = 0.013680, respectively:

P_c (psia) = 678 - 50 · (γ_g - 0.5) - 206.7 · X_N2 + 440 · X_CO2 + 606.7 · X_H2S

T_c(R) = 326 + 315.7 · (γg - 0.5) - 240 · X_N2 - 88.3 · XCO₂ + 133.3 · X_H2S

(11) Calculate reduced pressure, P_r, and reduced temperature, T_r, using the following equations with:  the bottom hole pressure, P_BH, as determined in paragraph (b)(1) of this section;  the bottom hole temperature, T_BH (F), as determined in paragraph (b)(2) of this section in the following equations:

(15) Calculate the flow rate of water in the well, q_w (cu ft/sec), using the following equation with the water production rate Qw (bbl/day) at the well site: