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Studies of a Relative Permeability Modifier Treatment Performed Using Multitap Flow Cells

2000; Linguagem: Inglês

10.2118/59346-ms

E. Dwyann Dalrymple, Larry Eoff, B. R. Reddy, C. Wouter Botermans, David Brown, S. G. R. Brown,

Enhanced Oil Recovery Techniques

Abstract Relative permeability modifier (RPM) treatments are designed to (1) reduce the quantity of water produced from the formation or (2) reduce the water-oil ratio (WOR) of the produced fluids without significantly damaging the hydrocarbon-production potential of the zone. Ideally, the RPM chemical should alter the flow properties of the fluids traveling through pore spaces rather than block the pore spaces. However, the laboratory methods and procedures typically used for evaluating RPM's are actually modified versions of those used for evaluating full blocking agents. The RPM effect is measured by determining the changes in the drag forces through the pore throats to specific fluids (water, oil, and gas) rather than simply blocking the pore throats to the flow of all fluids. Therefore, a different approach was used in the physical-model flow-testing procedure. Flow studies were performed to measure the effectiveness of RPM treatments at distinct points throughout the core as the fluids traveled through rock test cores. The following water- and oil-saturation levels were examined: 100% water water with residual oil oil with residual water Permeability was varied between −2000 md and 20 md. Placement procedures were also varied. Some tests included single cores; others included treatments of two cores arranged to represent parallel flow stringers within a formation. The two cores, arranged in parallel, were saturated using a method to best represent the type of layer desired; one core represented a water layer, and the other represented an oil layer. A bullhead technique was used for placing the RPM chemical. Both carbonate and sandstone lithologies were examined. This paper compares the results of conventional testing methods to those of testing methods used for the multipressure tap flow procedure. The results illustrate the importance of examining fluid flow throughout the length of the formation rock sample instead of simply evaluating a single measurement across the entire core. By using a multipressure tap flow cell to determine the effect of permeability changes throughout the length of the core, it was possible to help prevent the observed data from being skewed by "end" effects. This paper also describes laboratory procedures and schematics of the physical laboratory-scale model. Operators can use this information to (1) determine whether an RPM treatment can be applied to water-production problems resulting from sources such as coning and high-permeability streaks, (2) assess the potential damage to hydrocarbon production caused by such treatments, and (3) calculate the treatment volumes necessary for addressing different types of water-production problems.