Optimization of Fracture Parameters for Hydraulic Fractured Horizontal Well in a Heterogeneous Tight Reservoir: An Equivalent Homogeneous Modelling Approach

Abstract

Building numerical reservoir simulation model with a view to model actual case requires enormous amount of data and information. Such modeling and simulation processes normally require lengthy time and different sets of field data and experimental tests that are usually very expensive. In addition, the availability, quality and accessibility of all necessary data are very limited, especially for the green field. The degree of complexities of such modelling increases significantly especially in the case of heterogeneous nature typically inherited in unconventional reservoirs. In this perspective, this study focuses on exploring the possibility of simplifying the numerical simulation process without compromising the accuracy of results for heterogeneous unconventional tight gas reservoir with an emphasis on optimisation of multi-stage hydraulic fractured parameters, such as fracture half-length and number of fractures towards maximization the net present value (NPV). The key objectives of this study are to mitigate the effect of reservoir heterogeneity through building an equivalent simplified homogeneous reservoir simulation model for forecasting the production performance of fractured horizontal well in a heterogeneous carbonate tight gas reservoir and optimize the fracture parameters such as number of fractures and fracture half-length based on maximizing the NPV. The homogeneous model, which is equivalent to a heterogeneous reservoir model was built based on the statistical analysis of the rock properties of heterogeneous model. The simulation results obtained were analysed for a number of cases covering a range of fracture number (from 1 to 80), fracture half-length (from 500 to 2000 ft). The result demonstrated that the simplified equivalent homogeneous model has the ability to provide a good estimate for production forecasting, and determine the optimum number of fractures and fracture half-length within a high accuracy. The model is simple, yet provides good approximation with high accuracy, but save huge computation time.