Oil & Gas Apps 

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Easy to use engineering apps for the oil and gas industry  designed for practical field applications. Designed for iPhone or iPad  available from the AppStore. 
Available Apps  
Info 
GasLeak calculates leakrates from oil and gas leaks in oil and gas operations and equipment. 
GasLeak  Documentation 
Free iPhone App


Info 
AGA3 calculates size, flowrate or pressure drop for gas and liquid flow orifice meters based on the American Gas Association AGA report No. 3 (also API Manual of Petroleum Measurement Standards, Chapter 14.3). 
AGA3  Documentation 

Info 
ISO5167 calculates size, flowrate or pressure drop for gas and liquid flow orifice meters based on International Standard ISO51672:2003.  
Info 
Restrict_Ori calculates size and flowrates for gas and liquid restriction orifice meters based on R.W. Miller's "Flow Measurement Handbook". 
Restrict_Ori on the App Store


Info 
Oil&GasPVT calculates physical properties (PVT) of Gases (Natural Gas, Air and Nitrogen) and Liquids (Oil, Water, MeOH, MEG, DEG and TEG) based on published correlations. 
Free iPhone App


LineFit performs straight line regression calculation for X, Yvalue pairs by method of Least Squares.  LineFit  Documentation 
Free iPhone App


CurveFit uses regression analysis by method of least squares to fit different equations to a data set. Up to 10 different equations can be fitted to the data.  CurveFit  Documentation 
Free iPhone App


Privacy Policy: We do not collect any usage data, personal information, or any other information from users. We do not employ thirdparty companies, except the App Store for downloading and purchasing our apps. Note that users must accept the Disclaimer/Warranty stated below. This policy is effective as of 20210521 and may be updated from time to time and any changes will be posted on this page. Disclaimer/Warranty: Users of the apps must accept this disclaimer of warranty: Each app is provided "as is" without warranty of any kind, either expressed or implied, including any warranty of merchantability or fitness for a particular purpose. In no event shall the Author/Developer be held liable for any loss of profit, special, incidental, consequential, or other similar claims. If there are any questions or suggestions for our apps, please contact us at: oilgasapp@gmail.com 



AGA3 Orifice
AGA3 Orifice calculations are based on the American Gas Association AGA report No. 3 (also API Manual of Petroleum Measurement Standards, Chapter 14.3). Orifice size is calculated from given flowrate and pressure drop, Flowrate is calculated from given size and pressure drop and Pressure Drop requires orifice size and flowrate. Different taps can be selected: Flange taps or Pipe taps. Fluids include gases: Natural Gas (Specific Gravity must be provided), Air and Nitrogen, or liquids: Crude Oil, Water, Methanol, Monoethylene Glycol, Diethylene Glycol and Triethylene Glycol. In addition, selecting orifice material will adjust the sizing parameter of the orifice depending on temperature. Physical Properties For natural gas the AGA8 equationofstate (EOS) is used for calculating Zfactor (compressibility factor) specific heat capacity and isentropic coefficient. For air and nitrogen, the RedlichKwong EOS is used. Other physical properties are calculated from common empirical equations used in the oil and gas industry (viscosity, pseudocritical properties). For liquids, the physical properties are calculated from common empirical equations used in the oil industry. Orifice Meters with Flange Taps:
Q_{m }=359.072C_{d}(FT)E_{v}Y_{1}d^{2}𝜌_{1}DP where Qm = mass flow rate (lbm/hr) 359.072 = Conversion factor for flowrate in lbm/hr, d in inches, and DP in inches H2O Cd(FT) = coefficient of discharge for flange tapped orifice meters Ev = velocity of approach factor Y1 = expansion factor (upstream tap) d = orifice plate bore diameter, inches 𝜌_{1} = density of fluid at upstream flowing conditions, lbm/ft3 DP = orifice differential pressure, inches H2O at 60 °F Cd(FT) = Ci(FT) + 0.000511 × (1,000,000 × ß/ReD)^0.7 + {0.0210 + 0.0049 × (19,000 × ß/ReD)^0.8} × ß4 × (1,000,000/ReD)^0.35
Ci(CT) = 0.5961+ 0.0291 × ß^2  0.2290 × ß^8 If pipe diameter is less than 2.8 inches, the Ci(CT) orifice calculation factor is modified as follows with D in inches: Ci(CT) = Ci(CT) + 0.003 × (1ß) × (2.8  D) ReD = Reynolds number for the pipe, dimensionless = 𝜌_{1}𝑣𝐷/μ 𝑣 = fluid velocity D = pipe diameter μ = viscosity Ev = velocity of approach factor = (1  ß^4)^0.5 Y1 = expansion factor (upstream tap) = 1 – (0.3625 + 0.1027×β^4 + 1.1320 × β^8) × {1 – [P2/P1]1/κ} ß. = diameter ratio, (d/D) κ. = isentropic coefficient P1, P2 = pressure at upstream and downstream tap respectively Orifice Meters with Pipe Taps: Current AGA/API Standard does not contain details of pipe tap orifice metering, but refer to the 1992 Standard (3rd Edition), which uses the factormethod for calculation of flow orifices. For gas orifices: Q_{v }=C^{* }√(P_{1}h_{w)} where Qv = volumetric flowrate, ft3/hr Fb = basic orifice factor = 338.178d2 K0 Fpb = base pressure factor Ke = coefficient of discharge when Reynolds number = 1,000,000 x d/15 E = d × (905  5000 × ß + 9000 × ß^2  4200 × ß^3 + 875/D) ß = diameter ratio, (d/D) κ = isentropic coefficient For liquid orifices, the equation reduces to: Q_{v }=C^{* }√h_{w} where Q_{v} = volumetric flowrate, GPH C^{* }= orifice flow constant = F_{b}F_{r}F_{pb}F_{tb}F_{tf}F_{gr} From K_{0} and K_{e} above it can be shown that the discharge coefficient at any Reynolds number is: K = K_{o} x (1 + E/R_{eD}) Home  Download 

ISO5167 Orifice The rate of mass flow is related to the pressure differential according to: Qm = C x E x ¶/4 x d² x √(2 x DP x 𝜌_{1}) where Q_{m }= mass flow rate (kg/s) C = discharge coefficient = alpha/E E = velocity of approach factor = (1 ß^{4})^{0.5} d = orifice diameter at actual flowing conditions, m DP = Pressure drop across the orifice (P1  P2), Pascal 𝜌_{1} = density of flowing fluid measured at upstream tap, kg/m^{3} alpha = flow coefficient = CE ß = d/D The discharge coefficient, C, and the expansion factor are determined empirically: C = 0.5961 + 0.0261ß^{2 } 0.216ß^{8 }+ 0.000521 × [10^{6} × β /R_{eD}]^{0.7 }+ (0.0188 + 0.0063A)ß^{3.5 }× [10^{6}/R_{eD}]^{0.3 }+ (0.043 + 0.080e^{10L}_{1 } 0.216e^{7L}_{1}) × (1  0.11A) × (β^{4}/(1  β^{4}))  0.031(M’_{2 } 0.8M’_{2}^{1.1}) β^{1.3} If D<71.12 mm (2.8 in), the following term must be added to the above equation: + 0.011(0.75β) x (2.8D/25.4) (D in millimeter) where R_{eD }= pipe Reynolds number M’_{2} = 2L’_{2}/(1β) A = (19000β/R_{eD})^{0.8} For corner taps: L_{1} = L’_{2} = 0 For D and D/2 taps: L_{1} = 1.0 and L’_{2} = 0.47 For flange taps: L_{1} = L’_{2} = 25.4/D (D in millimeter)
The expansion factor is given as: Epsilon = 1 – (0.351 + 0.256ß^{4 }+ 0.93ß^{8}){1[p_{2}/p_{1}]^{1/}^{κ}_{ }} 

Restriction orifice calculations are performed according to R. W. Miller's "Flow Measurement Engineering Handbook". Gas Restriction Orifices For gases restriction orifices are calculated based on critical flow, which means that sonic velocity (critical flow) exists at the orifice throat, and further decrease in the downstream pressure will not increase the mass flow rate. For critical flow the basic mass flow rate equation is: 𝑄𝑚 = 1336.485 × 𝐶 × 𝑑² × √(𝑍 × Y_{CR }× 𝜌 × F_{TP} × P) where 𝑄𝑚_{ }= mass flow rate, lb_{m} /h C = critical discharge coefficient d = orifice diameter at flowing conditions, in Y_{CR }= critical flow function F_{TP }= total pressure correction factor to adjust for difference between static pressure read at the pipe wall (Manometer) and total pressure of the fluid and Z, 𝜌 and P are measured at flowing upstream conditions For ßratios less than 0.5 the total pressure correction factors are approximated by: F_{TP} = {1  k/2[2/(k+1)]^{[(k+1)/(k1)]} × ß^{4}}^{1 } Y_{CR} = {k/Z×[2/(k+1)]^{[(k+1)/(k1)]}}^{0.5 } where k = isentropic coefficient at flowing conditions Assuming steady isentropic flow, critical flow (choked flow) occurs when: P_{2}/P_{1}/F_{TP} < [2/(k+1)]^{[k/(k1)]} where P_{1 }= pressure upstream orifice P_{2 }= pressure downstream orifice By assuming sharpedged orifices with plate thickness to bore diameter between 1 and 6 the discharge coefficient is a constant given as: C = 0.83932 Liquid Restriction Orifices Liquid choked flow occurs if a cavitation barrier exists within an orifice. Only upstream pressure increases can increase flowrates. However, generally for liquids, the vapor pressure will be lower than atmospheric pressure (except volatile fluids like light crude oils and methanol), so choked flow likely will not occur. Therefore, in this app, if vapor pressure is found to be lower than given downstream pressure, the pressure drop is calculated based on control valve pressure drop calculations: Choked Flow (Critical Flow) (P_{2} < P_{V}): ΔP = P_{1}  P_{V} NonChoked Flow (NonCritical Flow (P_{2} >= P_{V}): ΔP = P_{1}  [0.96 – 0.28 * (P_{V }/P_{Crit})] * P_{V} Thick squareedged orifices are used as they are inexpensive. The sizing and flowrate equation used for liquids is: Qm = C × E × ¶/4 × d² × √(2 x DP x 𝜌_{1}) where 𝑄𝑚_{ }= mass flow rate, lb_{m} /h C = critical discharge coefficient E = velocity of approach factor = (1 ß^{4})^{0.5} d = orifice diameter at flowing conditions DP = Pressure Drop, calculated as per above, depending on P_{v} and P_{2}, Pa (Pascal) P_{1} = Upstream orifice pressure, Pa P_{2} = Downstream orifice pressure, Pa P_{V} = Vapor Pressure, Pa 𝜌_{1 }= density of fluid at upstream pressure, kg/m^{3} For nonchoked flow, the app will estimate a Cavitation Index: CI = (P_{2} – P_{v}) / (P_{1} – P_{2}) where subscripts 1 and 2 refer to upstream and downstream pressures respectively. If the Cavitation Index is less than the acceptable cavitation level, sigma, cavitation is likely to occur at the orifice outlet, and the app will give a warning and the calculated cavitation index (CI) is shown compared to acceptable index, sigma. Assuming squareedged orifices with plate thickness to bore diameter less than 6 with a minimum of 0.125 in (3 mm), the liquid restriction orifice constant used in this app is: C = 0.6 Home  Download 

Oil&GasPVT Oi&GasPVT calculates physical properties for gases (Natural Gas, Air and Nitrogen) and liquids (Crude Oil, Water, Methanol (MeOH), Monoethylene Glycol (MEG), Diethylene Glycol (DEG) and Triethylene Glycol (DEG)). Gas properties:
Liquid properties:
Standard conditions are defined as 60 °F (15.6 °C) and 14.696 psia (1.01325 Bara). Calculations are based on customary units unless noted (Temperature = °F, Pressure = psia, Density = lb/ft3, etc.). Generally, pseudocritical properties and pseudoreduced properties are used throughout the app. 

Updated Feb 18, 2021  Copyright © Norcraft  2021 