Brief: A Study of the Effect of Drilling-Fluid Fines on Reservoir Performance

Abstract

Introduction Most oilfield drilling is undertaken for the purpose of producing hydrocarbons. During the era of high oil and gas prices, little attention was paid to the effect that the process of penetrating the reservoir had on its ability to release hydrocarbons. In the current climate of reduced pricing, the subject of reservoir impairment has become the focus of widespread industry attention. One of the most damaging effects that a drilling fluid can have on reservoir producibility is caused by the presence of fine solids in the fluid. This work, carried out at Schlumberger Cambridge Research, focused on understanding the mechanisms by which fines invade sandstone matrices and the circumstances under which such invasion occurs. We further pursued an understanding of the mechanisms underlying the unexpectedly low damaging performance being observed with fluids based on a complex formed between conventional oilfield grade bentonite and highly cationic mixed metal hydroxide (MMH) crystals. All investigations have been directed at an openhole, nonperforated completion scenario.