Pressure and pressure derivative analysis for injection tests with variable temperature without type-curve matching

  • Freddy Humberto Escobar Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
  • Javier Andrés Martínez Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
  • Matilde Montealegre M. Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
Keywords: permeability, radial flow, anisothermical flow, mobility, injection front

Abstract

The analysis of injection tests under nonisothermic conditions is important for the accurate estimation of the reservoir permeability and the well's skin factor; since previously an isothermical system was assumed without taking into account a moving temperature front which expands with time plus the consequent changes in both viscosity and mobility between the cold and the hot zone of the reservoir which leads to unreliable estimation of the reservoir and well parameters. To construct the solution an analytical approach presented by Boughrara and Peres (2007) was used. That solution was initially introduced for the calculation of the injection pressure in an isothermic system. It was later modified by Boughrara and Reynolds (2007) to consider a system with variable temperature in vertical wells. In this work, the pressure response was obtained by numerical solution of the anisothermical model using the Gauss Quadrature method to solve the integrals, and assuming that both injection and reservoir temperatures were kept constant during the injection process and the water saturation is uniform throughout the reservoir. For interpretation purposes, a technique based upon the unique features of the pressure and pressure derivative curves were used without employing type-curve matching (TDS technique). The formulation was verified by its application to field and synthetic examples. As expected, increasing reservoir temperature causes a decrement in the mobility ratio, then estimation of reservoir permeability is some less accurate from the second radial flow, especially, as the mobility ratio increases.

References

Benson, S. M., & Bodvarsson, G. S. (1986). Nonisothermal Effects During Injection and Falloff Test. SPE Formation Evaluation, Feb. 1986: 53-63. https://doi.org/10.2118/11137-PA

Boughrara, A. A., & Reynolds, A. C. (2007). Practical Analysis of Injection / Falloff Data of Horizontal Wells. Paper SPE 109799, presented at the ATCE 2007 held in Anaheim, California, Nov. 11-14. https://doi.org/10.2118/109799-MS

Boughrara, A. A., & Peres, A. M. (2007). Approximate Analytical Solutions for the Pressure Response at a Water- Injection Well. J. Petroleum Scien. and Engineer., March 2007, 12 (1): 19-34. https://doi.org/10.2118/90079-PA

Platenkamp, R. J., (1985). Temperature Distribution Around Water Injectors: Effects on Injection Performance. Paper SPE 13476 Middle East Oil Technical Conference and Exhibition held in Bahrain, March 11-14. https://doi.org/10.2118/13746-MS

Tiab, D., (1995). Analysis of Pressure and Pressure Derivative without Type-Curve Matching: 1- Skin Factor and Wellbore Storag. J. Petroleum Scien and Engineer. January 1995, 12 (3): 171-181. https://doi.org/10.1016/0920-4105(94)00040-B

How to Cite
Escobar, F. H., Martínez, J. A., & Montealegre M., M. (2008). Pressure and pressure derivative analysis for injection tests with variable temperature without type-curve matching. CT&F - Ciencia, Tecnología Y Futuro, 3(4), 83–91. https://doi.org/10.29047/01225383.464

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Published
2008-12-31
Section
Scientific and Technological Research Articles

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