1、Calculations in Chapter 2-Definition of Intermittent Gas-LiftFieldWellInputField UnitsEqn.2.2.1-Volume of gas per cycleAtarea of the tubing0.15ft2Lvpoint of injection depth6000.00ftPtaverage tubing pressure when the slug reaches the surface50.00psiabase pressure in filed units14.70psiaVgs=3061.22ft3
2、Eqn.2.2.2-Liquid produced per cycleLsluginitial slug length100.00ftFBFfall back factor 0.06fractionAtarea of the tubing0.15ft2Lvpoint of injection depth6000.00ftQL=1.71bblEqn.2.2.3-Injection Gas Liquid RatioLvpoint of injection depth6000.00ftLsluginitial slug length100.00ftPtaverage tubing pressure
3、when the slug reaches the surface50.00psiRGL=1781.25cu ft/bblEqn.2.2.4-High pressure storage volumeNmaximum number of wells injecting gas simultaneously24Qgiaaverage per-well injection rate100.00cu ft/minQgicmaximum compressor output2000.00cu ft/minbase pressure in filed units14.70psigTaverage injec
4、tion time5.00min/cyclePddischarge pressure1000.00psigPcmaximum required well surface injection pressure950.00psigVh=588.00ft3Eqn.2.2.5-Low pressure storage volumeNmaximum number of wells injecting gas simultaneously24Qgiaaverage per-well injection rate100.00cu ft/minQgicmaximum compressor output2000
5、.00cu ft/minbase pressure in filed units14.70psigTaverage injection time5.00min/cyclettime takes for the gas to pass the separator5.00minutesPIlow-pressure or suction storage pressure25.00psigPcicompressor intake pressure10.00psigVL=1960.00ft3Calculations in Chapter 3-Types of InstallationsFieldWell
6、InputField UnitsEqn.3.5.1-Fallback rateVplplunger velocity10.00ft/secs1Vpl-axis intercept for a particular plunger type5.00ft/secs2slope1.00(gal/sec)/(ft/sec)FB=0.12bbl/secEqn.3.5.2-Fallback lossFBfallback rate1.00bbl/secttime increament10.00secD DFB=10.00bblEqn.3.5.3-Updated slug lengthLtlength of
7、the slug250.00ftFBfallback loss0.03bblBtVolumetric capacity of the tubing1.00bbl/ftLt+D Dt=249.97ftCalculations in Chapter 5-Design of Intermittent LiftFieldWellInputField UnitsEqn.5.2.1-Volume of gas per cyclePpdtubing pressure at valve depth when valve opens1000.00psiaDvdepth of the valve1500.00ft
8、Btvolumetric capacity of the tubing1.00cu ft/ftQ=102040.82ft3Eqn.5.4.1-Valve area ratioPiodthe injection opening pressure at valve depth1500.00psiaPvcdvalve closing pressure at depth1000.00psiaPpodproduction pressure in the tubing when the valve opens1200.00psiaR=1.67fractionEqn.5.4.2-Tubing opening
9、 pressurefggas pressure correction factor 0.90Pwhwellhead pressure 1200.00psiPfliquid gradient0.80psi/ftQliquid column length800.00ftPpod=1720.00psiCalculations in Chapter 6-Troubleshooting Intermittent LiftFieldWellInputField UnitsEqn.6.3.2.1-Static liquid levelDptdepth of the top of the perforatio
10、ns1500.00ftPsbhbottom hole pressure1800.00psiPwhwellhead pressure800.00psirfliquid gradient0.80psi/ftDsl=250.00ftEqn.6.3.2.2-Liquid gradientwwater cut of the produced liquid0.50fractionAPIdegree of API25.00APIr rf=0.41psi/ftEqn.6.3.2.3-Initial liquid column lengthTcycle time in minutes25.00minqfprod
11、uction12.00bbl/DayDttubing inside diameter15.00inchFFliquid fallback factor0.05fractionDovvalve depth1500.00ftQ=1.03ftEqn.6.3.2.4-Volume of Gas Injected Per CycleQgidaily gas flow rate1.20Mscf/DayTcycle time in minutes25.00minVg=20.83scft/cycleEqn.6.3.2.5-Tubing opening pressure at valve depthfgwell
12、head pressure correction factor1.20fractionPwhwellhead pressure800.00psirfliquid gradient0.80psi/ftQinitial column lenght420.00ftPpod=1296.00psiEqn.6.3.2.6-Wellhead pressure correction factor due to the gas column above the liquidDovvalve depth1500.00ftQinitial column length420.00ftfg=1.03fractionEq
13、n.6.3.2.7-Surface opening injection pressurePtrctest rack closing pressure100.00psiPpodtubing opening pressure at valve depth800.00psiRarea ratio3.00fractionFGLgas factor0.50fractionPio=2300.00psiEqn.6.3.2.8-Surface opening injection pressurePtrotest rack opening pressure100.00psiPpodtubing opening
14、pressure at valve depth800.00psiRarea ratio3.00fractionFGLgas factor0.50fractionPio=2600.00psiEqn.6.3.2.9-Surface opening injection pressurePbtbellows pressure at operating condition100.00psiStspring equivalane pressure cause by spring tension10.00psiPpodtubing opening pressure at valve depth800.00p
15、siRarea ratio3.00fractionFGLgas factor0.50fractionPio=2320.00psiEqn.6.3.2.10-Test rack bellows pressurePtrotest rack opening pressure100.00psiStspring equivalane pressure cause by spring tension10.00psiRarea ratio3.00fractionPb=-180.00psiEqn.6.3.2.11-Average productivity indextliquid accumulation ti
16、me10.00minrfliquid gradient0.80psi/ftDttubing inside diameter15.00inchAlff-200.00PI=7867.53bbl ft Day/psiEqn.6.3.2.12-AlffAs-1000.00psiFFfall back factor0.05fractionDovdepth of operating valve1500.00ftQinitial column length420.00ftrfliquid gradient0.80psi/ftAlff=0.38fractionEqn.6.3.2.13-AsPsbhstatic reservoir pressure1800.00psiDovdepth of operating valve1500.00ftDptdepth of the top of the perforations1500.00ftrTtrue liquid gradient0.80psi/ftPwhwellhead pressure800.00psifgwellhead pressure correc
