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A geochemical reaction-transport simulator for matrix acidizing analysis and design

1997; Elsevier BV; Volume: 17; Issue: 1-2 Linguagem: Inglês

10.1016/s0920-4105(96)00064-2

1873-4715

Xinghui Liu, Anne Ormond, Kirk Bartko, Ying Li, P. Ortoleva,

Enhanced Oil Recovery Techniques

A new two-dimensional geochemical simulator, CIRF.A, and its application to matrix acidizing analysis and design are presented. The simulator is based on the solution of the equations of fully coupled fluid flow, species transport and rock/fluid reactions and includes the effects of grain growth/dissolution and the alteration of porosity and permeability due to mineral reactions. Our program has a large built-in thermodynamic and kinetic database. The simulator is tested by laboratory core acidizing results. It is demonstrated that simulation results are in good agreement with experimental observations. Both laboratory and simulation results indicate that an acidizing treatment may induce formation damage due to the precipitation of byproducts from the reactions of acids with rock minerals. A series of simulation runs have been carried out under different conditions to determine the strategy for minimizing the acid induced formation damage. High injection velocity and higher acid concentration are shown to reduce mineral precipitation and formation damage. The simulator is also used to predict permeability and productivity improvements for typical acid treatments of undamaged and damaged wells in sandstone formations. Our simulator is shown to be capable of simulating all the sandstone acidizing procedures that include pre-flush, mud acid treatment, after-flush and back production. In carbonate formations, matrix acidizing may lead to the development of dissolution fingers and the creation of wormholes. It is demonstrated that the simulator can also capture the fingering and wormholing phenomena. We believe this new geochemical simulator is an invaluable tool for matrix acidizing analysis and design.