致密砂岩油藏水平井密切割压裂改造参数优化

Optimization of parameters of close cutting fracturing for horizontal well in tight sandstone reservoir

任佳伟,张先敏,王贤君,王维

中国石油长庆油田分公司油气工艺研究院，陕西 西安 710018 2．低渗透油气田勘探开发国家工程实验室，陕西 西安710018 中国石油大学（华东）石油工程学院，山东 青岛 266580 中国石油大庆油田有限责任公司采油工程研究院，黑龙江 大庆 163000

致密砂岩油藏压裂水平井存在产能递减严重、整体采出程度低等问题。为提高压裂增产效果，文中从研究裂缝扩展规律及扩展形态入手，基于扩展有限元方法建立裂缝扩展数值模型，明确了天然裂缝发育及小水平应力差是形成复杂缝网的必要条件，阐述了密切割压裂改造技术在目标油藏的适用性。基于地质工程一体化思想，利用数值模拟方法，在保持压裂投入不变的前提下，对比不同裂缝参数组合方案的产油能力。结果表明，“密切割+中低导流能力”的压裂设计方式，可有效提高单井产量。密切割压裂矿场试验表明，水平井压后初期日产油量为11.09 t，投产4 a后日产油量稳定在4.04 t，取得了较好的增产效果。研究成果对致密砂岩油藏水平井压裂优化设计具有借鉴意义。

Fractured horizontal wells in tight reservoirs have serious productivity decline and low overall recovery degree. To further improve the effect of fracturing stimulation, a fracture numerical model is established by studying the law and form of fracture propagation and based on extended finite element method. It is clear that the development of natural fractures and the small horizontal stress difference are the necessary conditions for the formation of complex fracture network, and the applicability of the close cutting fracturing technology in the target reservoir is explained. Based on the idea of geology-engineering integration, numerical simulation method was used to compare the oil production capacity of different fracture parameter combinations under the same fracturing investment conditions. The results show that the fracturing design method of "close cutting + medium-low conductivity" can effectively improve the production of single well. The close cutting field test shows that the initial oil production of horizontal well after fracturing is 11.09 t, and the daily oil production is stable at 4.04 t after four years of production, achieving a good effect of increasing production. The research results are of reference significance to the optimal fracturing design of horizontal well in tight reservoir.

10.6056/dkyqt202106025