Accounting for fluid-property variations in temperature-transient analysis

Document Type

Article

Publication Date

6-1-2018

Abstract

Significant fluid-property variation can be induced with pressure and temperature dynamics in the reservoir associated with oil production. The existing analytical solutions for temperature-transient analysis (TTA) generally assume constant fluid properties, which can be invalid especially for cases of high drawdown and strong temperature signals. In this study, we present a method to account for the fluid-property variations in TTA. The method introduces corrections on fluid-property values as input for analytical solutions, considering the quasilinear behavior of the temporal Joule-Thomson effect on a semilog plot. The corrections are performed on four identified fluid properties in an iterative manner, which can be easily implemented in available temperature-analysis procedures. To validate the developed approach, we model drawdown- and buildup-transient-temperature signals with the fluid-property correction method for nondamaged and damaged reservoirs under different production rates and reservoir-fluid compositions. The analytical modeling results are compared with numerical simulations. In addition, by finding the dominating fluid property, a simplified approach of property correction is presented. Through application to example problems, we show that using the fluid-property correction method presented here can improve the permeability estimations by 60% for the conditions considered in this paper. We present a modified method for damaged reservoirs, which results in an additional 25% improvement on the permeability estimations. With these improvements, the applicability of TTA using analytical solutions can be extended from cases with limited sandface-temperature signals of a few degrees Celsius to stronger signals of 20 to 30C.

Publication Source (Journal or Book title)

SPE Journal

First Page

868

Last Page

884

This document is currently not available here.

Share

COinS