Hybrid Rate-Decline Models for the Analysis of Production Performance in Unconventional Reservoirs Conference Paper uri icon

abstract

  • Abstract Estimating reserves in unconventional gas reservoirs is problematic due to the longer transient flow periods exhibited throughout the production history. The common industry practice is to use the Arps empirical rate-decline relations (i.e., the exponential and hyperbolic decline relations), but these equations are only strictly applicable during boundary-dominated flow. Application of the Arps relations to transient flow often results in significant overestimation of reserves. Under these circumstances, there is an obvious need for a theoretically based rate-decline equation(s) that is applicable for all flow regimes. We developed three main rate-time relations and five supplementary rate-time relations which utilize power-law, stretched exponential, hyperbolic, and exponential components to properly model the behavior of a given set of rate-time data. The new rate-time relations are developed based on the characteristic behavior of rate-time data in unconventional reservoirs. We also present the application of the βq,cp-derivative function for rate-time data diagnostics. Data diagnostics verify that stretched exponential function is sufficient to model rate-time behavior in unconventional reservoirs. Power-law, hyperbolic, and exponential components are incorporated into the proposed models to represent early and late time behavior. And therefore the new rate-time relations are called hybrid rate-time decline models. We demonstrate that the new rate-time relations are well-suited for the estimation of ultimate recovery as well as for extrapolating production into the future. While our proposed models can be used for any system, we provide application almost exclusively for wells completed in unconventional reservoirs. As example applications, we present a variety of field examples using production data acquired from tight gas and shale gas reservoir systems.

name of conference

  • SPE Annual Technical Conference and Exhibition

published proceedings

  • All Days

author list (cited authors)

  • Ilk, D., Currie, S. M., Symmons, D., Rushing, J. A., & Blasingame, T. A

complete list of authors

  • Ilk, D||Currie, SM||Symmons, D||Rushing, JA||Blasingame, TA

publication date

  • January 1, 2010 11:11 AM

publisher

  • SPE  Publisher