Application of Decline Curve Analysis for Estimating Different Properties of Closed Fractured Reservoirs for Vertical Wells

Daryasafar, Amin; FathiNasab, Mohammad; Da Prat, Giovanni; Kharrat, Riyaz

doi:10.22050/ijogst.2017.30498.1275

Application of Decline Curve Analysis for Estimating Different Properties of Closed Fractured Reservoirs for Vertical Wells

Document Type : Research Paper

Authors

Amin Daryasafar ¹

Mohammad FathiNasab ²

Giovanni Da Prat ³

Riyaz Kharrat ⁴

¹ M.S. Student, Department of Petroleum Engineering, Ahwaz Faculty of Petroleum, Petroleum University of Technology, Ahwaz, Iran

² M.S., Student, Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran

³ Professor, Da Prat & Associates (Consulting Company), Buenos Aires, C1420, Argentina

⁴ Professor, Department of Petroleum Engineering, Montanuniversität Leoben, Austria

https://doi.org/10.22050/ijogst.2017.30498.1275

Abstract

In this paper, decline curve analysis is used for estimating different parameters of bounded naturally fractured reservoirs. This analysis technique is based on rate transient technique, and it is shown that if production rate is plotted against time on a semi-log graph, straight lines are obtained that can be used to determine important parameters of the closed fractured reservoirs. The equations are based on Warren and Root model. The comparison between the results of this technique and those of the conventional methods confirms its high proficiency in transient well testing. It should be noted that in conventional decline curve methods, parameters such as interporosity flow parameter and storage capacity ratio must be first obtained by previous methods like the build-up analysis, but in the proposed method all the main reservoir parameters can be calculated directly, which is one of the advantages of this method. This paper focuses on the interpretation of rate tests, and the starting points and slopes of straight lines are utilized with proper equations to solve directly for various properties. The main important aspect of the presented method is its accuracy since analytical solutions are used for calculating reservoir parameters.

Keywords

Decline Curve Analysis

Naturally Fractured Reservoirs

Pseudo-steady

Rate Transient

Reservoir Properties

State Condition

Subjects

Petroleum Engineering

References

Barenblatt, G.I. and Zheltov, Y.P., On Fundamental Equations of Flow of Homogeneous Liquids in Naturally Fractured Rocks, Doklady Akademii Nauk, USSR 132, No. 3, p. 545–548, 1960.

Bona, N., Radaelli, F., Ortenzi, A., De Poli, A., Pedduzi, C., and Giorgioni, M., Integrated Core Analysis for Fractured Reservoirs: Quantification of the Storage and Flow Capacity of Matrix, Vugs and Fractures, Spere, Vol. 6, p. 226–233, 2003.

Chen, H.Y., A Reservoir Engineer Characterization of the Austin Chalk Trend, M.S. Thesis, Texas A&M University, 1985.

Da Prat, G., Cinco-Ley, H., and Ramey, H.J.Jr., Decline Curve Analysis Using Type Curves for Two-porosity Systems, Society of Petroleum Engineers Journal, p. 354–362, 1981.

Daryasafar, A., Joukar, M., FathiNasab, M., Da Prat, G., Kharrat, R., Estimating the Properties of Naturally Fractured Reservoirs Using Rate Transient Decline Curve Analysis, Journal of Earth Science, Vol. 28, p. 848-856, 2017.

De Swaan, A., Influence of Shape and Skin of Matrix-rock Blocks on Pressure Transients in Fractured Reservoirs, SPE 15637, Society of Petroleum Engineers Journal, 1986.

Mavor, M.J. and Cinco-Ley, H., Transient Pressure Behavior of Naturally Fractured Reservoirs, Paper 7977 Presented at The SPE California Regional Meeting, p. 18–20, 1979.

Saidi, M.A., Reservoir Engineering of Fractured Reservoirs, Total Edition Press, p. 289, 1987.

Tiab, D., Igbokoyi, A., and Restrepo, D., Fracture Porosity from Pressure Transient Data, International Petroleum Conference, p. 8, 2007.

Tiab, D., Analysis of Pressure and Pressure Derivative without Type-curve Matching, Skin and Wellbore Storage, Journal of Petroleum Science and Engineer, Vol. 12, No. 171, Also, Paper Presented at the 1993 SPE Production Operations Symposium, Oklahoma City, OK, SPE 25423, p. 21–23, 1995.

Van Everdingen, A.F. and Hurst, W., The Application of the Laplace Transform to Flow Problems in Reservoirs, Trans., AIME (1949), 186, p. 305–324, 1949.

Warren, J.E. and Root, P.J., The Behavior of Naturally Fractured Reservoirs, Society of Petroleum Engineers Journal, p. 245–255, Transactions of the AIME, p. 228,1963.