School of Mechanics Science & Engineering, Northeast Petroleum University, Daqing, Heilongjiang, China.
Heilongjiang Key Laboratory of Petroleum and Petrochemical Multiphase Treatment and Pollution Prevention, Daqing, Heilongjiang, China.
PLoS One. 2021 Aug 18;16(8):e0255793. doi: 10.1371/journal.pone.0255793. eCollection 2021.
For staged multi-cluster fracturing, methods for controlling perforation friction to adjust the flow distribution of each cluster can effectively promote the uniform extension of multiple fractures but lacks a fast and quantitative optimization method for different perforation parameters of each cluster. By establishing a numerical model of single-stage three-cluster flow-limited fracturing under stress-seepage coupling, and based on the response surface optimization method, fully considering the impact of perforation parameters interaction among three perforation clusters, according to the regression equation fitted under the global response, the rapid optimization of perforation parameters of segmented multi-cluster fracturing model is realized. The results show that: in determining the three factors of the study, it is found that there is an obvious interaction between the number of intermediate cluster perforations and the number of cluster perforations on both sides, the number of cluster perforations on both sides and the diameter of intermediate cluster perforations, the response surface optimization method gives the optimal perforation parameter combination of three clusters of fractures under global response; When the perforation parameters were combined before optimization, the fracture length difference was 32.550m, and the intermediate perforation cluster evolved into invalid perforation cluster, when the perforation parameters were combined after optimization, the fracture length difference was 0.528m, the three perforation clusters spread uniformly, and there are no invalid clusters. At the same time, the regression equation under the response is optimized before and after the comparison between the predicted value of the equation and the actual simulation value. It is found that the estimated deviation rate of the equation before optimization is 1.2%, and the estimated deviation rate after optimization is 0.4%. The estimated deviation rates are all less, and the response regression equation based on the response surface optimization method can quickly optimize the perforation parameters. The response surface optimization method is suitable for the multi parameter optimization research of formation fracturing which is often affected by many geological and engineering factors. Combining with the engineering practice and integrating more factors to optimize the hydraulic fracturing parameters, it is of great significance to improve the success rate of hydraulic fracturing application.
对于分段多簇压裂，控制射孔摩阻以调整每个簇流量分布的方法可以有效地促进多个裂缝的均匀扩展，但缺乏针对每个簇不同射孔参数的快速定量优化方法。通过建立应力-渗流耦合下单级三簇限流压裂的数值模型，并基于响应面优化方法，充分考虑三个射孔簇之间射孔参数相互作用的影响，根据全局响应下拟合的回归方程，实现分段多簇压裂模型射孔参数的快速优化。结果表明：在确定研究的三个因素时，发现中间簇射孔数与两侧簇射孔数之间、两侧簇射孔数与中间簇射孔直径之间存在明显的相互作用，响应面优化方法给出了三个簇裂缝在全局响应下的最优射孔参数组合；在优化前进行射孔参数组合时，裂缝长度差为 32.550m，中间射孔簇演变为无效射孔簇，在优化后进行射孔参数组合时，裂缝长度差为 0.528m，三个射孔簇均匀扩展，不存在无效簇。同时，对响应前和响应后的回归方程进行优化，比较方程的预测值与实际模拟值之间的预测偏差率。发现优化前的估计偏差率为 1.2%，优化后的估计偏差率为 0.4%。估计偏差率都较小，基于响应面优化方法的响应回归方程可以快速优化射孔参数。响应面优化方法适用于受多种地质和工程因素影响的地层压裂多参数优化研究。结合工程实践，综合更多因素优化水力压裂参数，对提高水力压裂应用成功率具有重要意义。
