Many hydrocarbon-bearing carbonate formations are routinely stimulated by fracture acidizing. Concurrent with the desire for increased production is the need to optimize treatment design and to predict well response following treatment. Simulation of the fracture acidizing process is complicated by the fact that the rate and extent of chemical reaction must be predicted, in addition to modelling the growth of the hydraulic fracture. Treatment design is further complicated by the fact that reactive and non-reactive fluids display different leakoff characteristics and overall leakoff rates tend to increase throughout an acidizing treatment.

This paper describes the use of a fracture acidizing simulator which dynamically couples fracture geometry and acid spending calculations. The simulator has the ability to accept data which describe the specific reactivity and etching characteristics of a given formation. The inadequacies of utilizing standard reactivity data and generalized etched conductivity correlations are illustrated.

The paper takes an engineering approach to acidizing treatment design. It reviews various core tests which can be performed to evaluate the feasibility of successfully stimulating a formation by fracture acidizing and shows how the data can be used in conjunction with computer design programs. Field tests which allow estimation of in-situ fluid leakoff characteristics are reviewed and related to acidizing treatment design.

Case histories are given which illustrate how fracture acidizing treatment design can be optimized by integrating core testing, field testing, and computer simulation.

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