New finding on pressure response in long, narrow reservoirs

  • Freddy Humberto Escobar Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
  • Oscar Muñoz Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
  • Jairo Sepúlveda Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
  • Matilde Montealegre Universidad Surcolombiana, Programa de Ingeniería de Petróleos, Grupo de Investigación en Pruebas de Pozos, Neiva, Huila, Colombia
Keywords: image technique, linear flow regime, fluvial reservoirs, close boundaries, constante pressure boundaries, linear flow, radial flow, difussivity equation

Abstract

During the process of reservoir characterization using well test analysis, before defining the reservoir model, it is convenient to properly identify flow regimes, which appear as characteristic patterns or “fingerprints” exhibited by the pressure derivative curve, because they provide the geometry of the streamlines of the tested formation. A set of reservoir properties can be estimated using only a portion of the pressure transient data of the flow regime. However, there are few cases with unidentified behaviors that deserve our attention.  The ten flow regime patterns commonly recognized in the pressure or pressure derivative curves of vertical or horizontal wells are: radial, spherical, hemispherical, linear, bilinear, elliptical, pseudosteady, steady, double porosity or permeability and doubled slope. A ½ slope of the derivative trend is an indication of linear flow. If this shows up early, a hydraulic fractured well is dealt with, but if this shows up immediately after the radial flow regime an indication of a channel comes to our mind. A -½-slope line at early times of the derivative plot indicates either spherical or hemispherical flow. However, if this line is observed once linear flow vanishes we are facing an unidentified flow regime.  We present the case of a channel reservoir with a well off-centered with respect to the extreme boundaries and close to a constant pressure boundary. At early times, the radial flow regime is observed and is followed by the linear flow regime. Once the open boundary is reached by the pressure disturbance, a -½ slope is observed on the pressure derivative plot and it lasts until the far extreme is felt. We simulated this behavior and plotted the isobaric lines and found out that a parabolic behavior shows up during this period of time. A typical behavior was found in Colombia in a reservoir of the Eastern Planes basin.

References

Abdelaziz, B. and Tiab, D., "Pressure Behaviour of a Well Between Two Intersecting Leaky Faults". Nigeria Annual International Conference and Exhibition, Aug. 2-4. Abuja, Nigeria, SPE 88873.

Earlougher, R.C., Jr., 1977. "Advances in Well Test Analysis", Monograph Series 5, SPE, Dallas, TX., USA.

Escobar, F.H., Muñoz, O.F. and Sepúlveda J.A., 2004. "Horizontal Permeability Determination from the Elliptical Flow Regime for Horizontal Wells". CT&F - Ciencia, Tecnología y Futuro, 2 (5): 83-95.

Escobar, F.H., Saavedra, N.F., Hernández, C.M., Hernández, Y.A., Pilataxi, J.F., and Pinto, D.A., 2004. "Pressure and Pressure Derivative Analysis for Linear Homogeneous Reservoirs without Using Type-Curve Matching". 28th Annual SPE International Technical Conference and Exhibition, Abuja, Nigeria, Aug. 2-4. SPE 88874. https://doi.org/10.2118/88874-MS

Escobar, F.H., Tiab, D. and Jokhio, S.A., 2003. "Characterization of Leaky Boundaries from Transient Pressure Analysis". Production and Operations Symposium, Oklahoma City, Oklahoma, U.S.A., March 23-25. SPE 80908. https://doi.org/10.2118/80908-MS

Ispas, V., and Tiab, D., 1999. "New Method of Analyzing the Pressure behavior of a Well Near Multiple Boundary System". Latin American and Caribbean Petroleum Engineering Conference, Caracas, Venezuela, April 21- 23. SPE 53933. https://doi.org/10.2118/53933-MS

Joseph, J.A., 1984. "Unsteady-State Cylindrical, Spherical and Linear flow in Porous Media" Ph.D. Dissertation, University of Missouri-Rolla.

Rhagavan, R., 1993. "Well Test Analysis". Prentice Hall. New Jersey.

Tiab, D., 1993. "Analysis of Pressure and Pressure Derivative without Type-Curve Matching: 1- Skin Factor and Wellbore Storage". Production Operations Symposium, Oklahoma City, OK., March 21-23. SPE 25423, 203-216. Also, J. Petroleum Scien. and Engineer., 171-181.

Tiab, D., 1994. "Analysis of Pressure Derivative without Type-Curve Matching: Vertically Fractured Wells in Closed Systems". J. Petroleum Scien. and Engineer., 323-333. https://doi.org/10.1016/0920-4105(94)90050-7

Tiab, D., Azzougen, A., Escobar, F. H., and Berumen, S., 1999. "Analysis of Pressure Derivative Data of a Finite- Conductivity Fractures by the 'Direct Synthesis Technique'." Mid-Continent Operations Symposium Oklahoma City, OK., March 28-31. SPE 52201: Latin American and Caribbean Petroleum Engineering Conference, Caracas, Venezuela, April 21-23. https://doi.org/10.2118/52201-MS

Tiab, D. and Crichlow, H., 1979. "Pressure Analysis of Multiple-Sealing-Fault Systems and Bounded Reservoirs by Type-Curve Matching". J. Petroleum Scien. and Engineer., 378-392. https://doi.org/10.2118/6755-PA

Wong, D.W., Mothersele, C.D., Harrington, A.G. and Cinco-Ley, H., 1986. "Pressure Transient Analysis in Finite Linear Reservoirs Using Derivative and Conventional Techniques: Field Examples" 61st Annual technical Conference and Exhibition of the Soc. of Petroleum Engineers., New Orleans, LA., SPE 15421.

https://doi.org/10.2118/15421-MS

How to Cite
Escobar, F. H. ., Muñoz, O., Sepúlveda, J., & Montealegre, M. (2005). New finding on pressure response in long, narrow reservoirs. CT&F - Ciencia, Tecnología Y Futuro, 3(1), 151–160. https://doi.org/10.29047/01225383.513

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Published
2005-12-31
Section
Scientific and Technological Research Articles

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