The advent of multiple hydraulic fracturing technologies in horizontal wells has significantly increased the profitability of oil and gas fields’ development and is one of the reasons for the continued growth of multiple fracturing technologies in horizontal wells in newly drilled and completed wells. Moreover, ultra-low permeability reservoirs predominantly are developed by depletion drives mechanism using regular horizontal well systems with multiple hydraulic fractures, and hence, the question of multiple hydraulic fracture optimizations becomes crucial. Many research papers are aimed at finding the optimal number of fractures on a horizontally completed well, but less attention is given to the process of well pattern optimal parameters determination.
This research work is aimed at optimization of horizontal well pattern with multiple transverse hydraulic fractures of finite and infinite conductivities. The objective of this paper is to find optimal values of dimensionless parameters, which will yield the most effective development system and production on depletion drive. The efficiency criterion is based on maximizing the dimensionless productivity index (Jd) in pseudo-steady state flow to the well. This well pattern optimization problem was solved on the basis of a previously proposed semi-analytical model, in which the method of fundamental solutions (MFS) was used. The novelty of this work presents dimensionless correlation, convenient for engineering calculations of the optimal parameters for multiple-fractured horizontal well pattern.
Verification of the correctness of the proposed semi-analytical method and the correlation dependences were carried out using a commercial hydrodynamic simulator. The comparison of results of the hydrodynamic simulator and that of the proposed semi-analytical method showed that the relative deviation of the calculated values from the obtained correction dependence didn’t exceed 3 percent.The characteristics of the best development system, determined based on economic optimization were also well described and estimated by the proposed correlations. Evidence to these is presented in the last part of this work.
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