致密砂岩储层压裂效果地质—工程影响因素评价

Comprehensive evaluation of geological and engineering factors affecting fracturing effectiveness in tight sandstone reservoirs

宿航 李瑞雪 邓虎成 秦源蔚 伏美燕 何建华 曾青高 宋林珂 张家维

SU Hang LI Ruixue DENG Hucheng QIN Yuanwei FU Meiyan HE Jianhua ZENG Qinggao SONG Linke ZHANG Jiawei

成都理工大学 能源学院(页岩气现代产业学院), 成都 610059 油气藏地质及开发工程全国重点实验室(成都理工大学), 成都 610059 中国石油 西南油气田公司 致密油气勘探开发项目部, 成都 610051 中国石油 长庆油田分公司 工程技术监督中心, 西安 710018

College of Energy (College of Modern Shale Gas Industry), Chengdu University of Technology, Chengdu, Sichuan 610059, China State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China Tight Oil and Gas Exploration and Development Project Department, PetroChina Southwest Oil and Gasfield Company, Chengdu, Sichuan 610051, China Engineering Technology Supervision Center, PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China

我国致密砂岩储层具有巨大的油气储量和开发潜力，水平井水力压裂改造技术是致密砂岩储层开发的关键增产措施。川中—川西过渡带J气田侏罗系沙溪庙组致密砂岩储层受其岩石力学性质及地质力学特征差异影响，相近压裂工艺下各井压裂改造效果差距较大。为提高压裂改造的有效性及针对性，研究了表征岩石力学性质的脆性指数及表征地质力学特征的最小水平主应力、水平两向主应力差3个地质因素对压裂效果的影响。以水平两向主应力差为分类条件，将研究区地质条件由好到差分为Ⅰ类和Ⅱ类；分析两类地质条件下各类工程因素对压裂效果的影响，并给出了不同地质条件下的工程参数优选范围。采用层次分析法和灰色关联法计算了上述地质及工程参数对压裂改造效果的影响权重，建立了压裂改造效果定量评价模型。基于所建模型与压裂改造效果的相关程度，优选层次分析法所建模型用于评价研究区压裂改造效果，并验证上述研究给出的工程参数建议范围的合理性及压裂改造效果综合评价模型的适用性。不同地质条件下水平井压裂工程参数建议范围存在较大差别，地质条件较好的水平井工程参数建议范围明显比地质条件较差的范围更大。优选层次分析法建立了用于评价研究区压裂改造效果的地质—工程综合评价模型。

China's tight sandstone reservoirs possess immense hydrocarbon reserves with substantial development potential. Hydraulic fracturing in horizontal wells is a crucial enhancement method for developing these reservoirs. In tight sandstone reservoirs of the Jurassic Shaximiao Formation of the J gas field in the transitional zone between central and western Sichuan, differences in rock mechanical properties and geomechanical characteristics result in significant variations in fracturing effectiveness across wells despite similar fracturing processes. To enhance the effectiveness and specificity of fracturing, this study examined the impact of three geological factors—brittleness index, minimum horizontal principal stress, and differences between two horizontal principal stresses—on fracturing effectiveness. Based on the difference in horizontal principal stress, the geological conditions in the study area were classified into two categories, type Ⅰ and type Ⅱ, from favorable to less favorable. The influence of various engineering factors on fracturing effectiveness under these two types of geological conditions was analyzed, and optimal ranges for engineering parameters under these conditions were proposed. The Analytic Hierarchy Process (AHP) and Grey Relational Analysis (GRA) were employed to calculate the influence weight of each geological and engineering parameter on fracturing effectiveness, and then a quantitative evaluation model was established. Based on the correlation with fracturing effectiveness, the AHP-based model was selected as the optimal method to evaluate the fracturing effectiveness in the study area. It was also used to verify the rationality of the proposed ranges for engineering parameters outlined in the study and the applicability of the comprehensive evaluation model for fracturing effectiveness. This paper revealed significant differences in the suggested parameter ranges for horizontal well fracturing engineering under different geological conditions, with notably broader ranges for wells in more favorable conditions than those in less favorable ones. The AHP-based model was identified as the optimal geological and engineering comprehensive evaluation model for assessing the fracturing effectiveness in the study area.

国家自然科学基金面上项目 42072182;四川省杰出青年科技人才项目 2020JDJQ0058

https://doi.org/10.11781/sysydz2024061349