Abstract
Advanced laboratory reservoir conditions flood tests, performed on live reservoir fluids and core materials, have been used to simulate downhole operations such as seawater injection, drilling mud application, and chemical squeezes to identify any associated formation damage mechanisms (Francis et al, 1995). In many cases, return permeabilities are used to identify when formation damage has occurred, but in itself will not identify the actual mechanism such as scale precipitation, emulsion polymer blocks, solids invasion, bio-polymer/cell blockage, and H₂S production. In order to identify these mechanisms and to fully interpret the return permeability data, it is necessary to undertake additional analytical techniques, which include C.A.T. scanning, petrographic thin sections, dry and cryogenic S.E.M., and microbial growth studies. These analyses can be performed before and after tests for comparison, to identify the damage mechanisms. The various techniques and how they are used to fully interpret the return permeability data are discussed in this paper.