An integrated model for multiobjective design optimization of hydraulic fracturing

An integrated novel model for hydraulic fracturing design optimization is p resented, which recognizes complex interactions between a hydraulically cou pled fracture geometry module, a hydrocarbon production module and an inves tment-return cash flow module. Free design variables are identified and var ious design constraints are formulated, which must be satisfied so that an optimum design obtained is executable in the field using the specified surf ace equipment (pump, tubing, etc.) and that the treatment does not cause an y undesirable formation damage by uncontrolled fracture growth and/or multi ple secondary fracture initiation. The model is formulated within the frame work of a multivariate and multiobjective optimization method, which is bas ed on the combined features of Genetic Algorithm and Evolutionary Operation . A 2D fracture model is used to establish relationships between treatment parameters and fracture growth. The potential for hydraulic fracturing desi gn improvement is demonstrated by application to a tight gas reservoir. Res ults show that the proposed model is instrumental in improving hydraulic fr acturing design and achieving a goal-oriented optimum design in a conflicti ng environment. About 12% compromise with maximum possible production, or n et present value (NPV), over 10 years can save up to 44% of initial hydraul ic fracturing treatment cost. Furthermore, the 88% production, or net prese nt value, as a result of an optimum treatment program is significantly high er than any arbitrary design. The issues of real-time design modification, however, are not included in this study. (C) 2001 Elsevier Science B.V. All rights reserved.