Pressure and pressure derivative analysis in a reservoir with a finite-conductivity fault and contrast of mobilities

Abstract

Finite-conductivity faults present a very unique transient behavior. In general terms, as the fault is reached by the pressure disturbance the pressure derivative falls with forming a straight line with a slope of minus one, then bilinear flow takes place which is reflected by a quarter-slope seen on the pressure derivative curve. at much late time, the radial flow regime is reached again.

In this work, the signature of the pressure derivative curve for the reservoirs with finite-conductivity faults is  investigated to understand their behavior and facilitate the interpretation of well test data. This paper presents  the most complete analytical well pressure analysis methodology for finite-conductivity faulted systems when  mobility contrast, using some characteristics features found on the pressure and pressure derivative log-log plot Hence, new equations are introduced to estimate the fault conductivity for such systems. The proposed expression and methodology were successfully tested with synthetic cases.