Transient Pressure Response of Horizontal Wells in Layered and Naturally Fractured Reservoirs With Dual-Porosity Behavior

Abstract

ABSTRACTOver the last decade, extensive studies have been carried out on the behaviour of vertical well tests in dual porosity systems. Although some research has been done on the horizontal well counterpart [1-5], most of this work has just dealt with a specific situation. No systematic investigation has been yet reported on the behaviour of transient horizontal well tests in dual porosity systems. One of the major purposes of this study is to bridge this gap. An approximate analytic solution in real time space modelling the horizontal well test in a dual porosity reservoir is given. Responses for both pseudo-semi-steady-state (PSSS) and transient dual porosity models in linear flow are investigated.For homogeneous reservoirs the theory of pressure transient analysis for horizontal wells suggests that linear flow should be the dominant flow regime when L/h is large and the log-log derivative diagnostic would frequently exhibit a half slope. However field examples quoted in this paper do not show this feature nearly as often as one might anticipate and unexpectedly quarter slopes have been observed in many cases. The paper particularly illustrates how a bilinear flow can arise in the case of a horizontal well in a transient dual porosity (fractured or layered) reservoir.Several field examples are analysed to illustrate the horizontal well transient pressure response in linear flow.