Horizontal Well Performance Simulation

Prasad, Raj; Coble, L.E.

doi:10.2523/21087-ms

Cited by 7 publications

(1 citation statement)

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“…7 is calculated during a time step: cushion density=8.33 lb/gal, and reservoir fluid density at surface conditions=7 lb/gal. (19) Solution Technique…”

Section: )mentioning

confidence: 99%

Surge Test Simulation

Petak¹,

Prasad²,

Coble³

1991

Proceedings of Low Permeability Reservoirs Symposium

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Post-perforation surge tests are frequently used in the oil industry. A surge test is normally conducted by flowing fluids into a closed chamber. This category of testing includes backsurge perforation washing, underbalanced perforating with subsequent flow, and closed chamber drillstem testing. Typically, downhole response is measured by a pressure/temperature gauge. This response may be analyzed for reservoir parameters by using existing techniques; however, variable wellbore conditions and rapidly changing rates make fmding a solution difficult and sometimes impossible. This paper presents a numeric simulator which is used to model surge behavior for various wellbore and reservoir conditions. Because variable wellbore conditions are considered, the resulting analysis is more reliable and often possible when other techniques fail.Reservoir flow into the wellstring is controlled by the wellstorage coefficient and completion and reservoir parameters. At each time step the wellstorage coefficient is explicitly solved by performing a mass balance on the wellstring fluids. This calculation accounts for compression of air in the surge chamber, variable cushion pressure, displacement of rathole fluid into the wellstring, changing inside diameter in the wellstring, and volume of reservoir fluid produced into the wellstring.Simulated pressure profiles are presented for various reservoir and wellbore conditions. A simulated match of field test data is also given to illustrate the practicality of References and figures at end of paper. 259 this work. The matching process yields permeability, skin, static formation pressure, and radius of investigation.Surge Test Simulation SPE 21832occurring during this surge may be recorded and analyzed to determine formation parameters.Although a downhole valve may be present during this treatment, it is not typically used to control reservoir flow. The surface valve is usually closed during the flow.

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“…7 is calculated during a time step: cushion density=8.33 lb/gal, and reservoir fluid density at surface conditions=7 lb/gal. (19) Solution Technique…”

Section: )mentioning

confidence: 99%

Surge Test Simulation

Petak¹,

Prasad²,

Coble³

1991

Proceedings of Low Permeability Reservoirs Symposium

View full text Add to dashboard Cite

show abstract

Surge Test Simulation

Petak

Prasad

Coble

1991

Low Permeability Reservoirs Symposium

View full text Add to dashboard Cite

Post-perforation surge tests are frequently used in the oil industry. A surge test is normally conducted by flowing fluids into a closed chamber. This category of testing includes backsurge perforation washing, underbalanced perforating with subsequent flow, and closed chamber drillstem testing. Typically, downhole response is measured by a pressure/temperature gauge. This response may be analyzed for reservoir parameters by using existing techniques; however, variable wellbore conditions and rapidly changing rates make finding a solution difficult and sometimes impossible. This paper presents a numeric simulator which is used to model surge behavior for various wellbore and reservoir conditions. Because variable wellbore conditions are considered, the resulting analysis is more reliable and often possible when other techniques fail. Reservoir flow into the wellstring is controlled by the wellstorage coefficient and completion and reservoir parameters. At each time step the wellstorage coefficient is explicitly solved by performing a mass balance on the wellstring fluids. This calculation accounts for compression of air in the surge chamber, variable cushion pressure, displacement of rathole fluid into the wellstring, changing inside diameter in the wellstring, and volume of reservoir fluid produced into the wellstring. Simulated pressure profiles are presented for various reservoir and wellbore conditions. A simulated match of field test data is also given to illustrate the practicality of this work. The matching process yields permeability, skin, static formation pressure, and radius of investigation.

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Drillstem Test and Closed-Chamber Drillstem Test Simulation

Petak

Finley

Coble

1991

SPE Offshore Europe

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The Drillstem Test (DST) has been a popular form of well testing since the early 1900's. To aid in the completion process, the pressure response from a DST can be analyzed to determine formation pressure, permeability, and amount of well damage. A downhole valve is used to control flow into the wellstring in most DSTs. Typically, the reservoir is intermittently flowed and shut-in multiple times. A variation of a DST is a closed chamber DST. Usually, the DST buildup periods are analyzed by using Homer3 time or Odeh and Selig's5 method. Limited analysis capabilities exist for the flow periods. Most DST analysis techniques lack the completeness to obtain accurate reservoir parameters. This paper presents a numeric simulator which is used to model DST and closed chamber DST behavior for a wide range of reservoir and wellbore conditions. Because variable wellbore conditions are considered, analysis is more reliable and often possible when other techniques fail. Reservoir flow into the wellstring is controlled by wellbore and reservoir parameters. In this simulator, wellbore conditions are modelled by using a wellstorage coefficient which is solved at each time step by performing a mass balance on the wellstring fluids. Volume of produced reservoir fluid, rathole mud production, variable cushion pressure, closed chamber air compression, inner wellstring diameter changes, hole deviation, and variable wellstring volume are considered in the calculation. By accounting for these parameters, this model is more complete than existing models or analysis techniques. The wellstorage coefficient is linked with reservoir values to solve for rate and pressure. Simulated pressure profiles are presented for various reservoir and wellbore conditions. A simulated match of field test data is also given to illustrate the practicality of this work. The strengths and weaknesses of the simulator are briefly cited.

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Horizontal Well Performance Simulation

Cited by 7 publications

References 0 publications

Surge Test Simulation

Surge Test Simulation

Surge Test Simulation

Drillstem Test and Closed-Chamber Drillstem Test Simulation

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