威荣页岩气田压裂实践与认识

Practice and understanding of fracturing in Weirong shale gas field

杨永华 宋燕高 王兴文 刘林 慈建发 林立世

YANG Yonghua SONG Yangao WANG Xingwen LIU Lin CI Jianfa LIN Lishi

中国石化 西南油气分公司 石油工程技术研究院, 四川 德阳 618000

Research Institute of Petroleum Engineering Co., Ltd., SINOPEC Southwest Oil & Gas Company, Deyang, Sichuan 618000, China

相比于中浅层，威荣深层页岩气工程地质特征更复杂，具有地应力高、水平应力差高、塑性高、地层压力高的“四高”特征，复杂的工程地质特征带来难以形成复杂缝网、人工裂缝难以支撑与保持及套变异常情况频发三大挑战，具体表现结果就是气井压后单井最终可采储量低。为解决上述难题，经过坚持不懈的探索和实践，压裂工艺在不断发现问题、解决问题过程中持续进步，探索形成了一套基于均衡压裂理念的“精细优化+实时预警+控运行节奏+W型井网”的预防套变及提高压后产量的系列措施。采用该工艺推广应用39井次，压裂效果不断提升，单井平均最终可采储量提高了500×104 m3，套变率从2022年的42.4%降低至目前的16.67%。由于邻井老井生产影响新压裂投产井，导致新井压后产量低于前期，现有400 m(一期)/300 m(二期)井距，压裂规模有下降优化的空间。后续新井应该在剩余储量基础上差异化优化，持续做好压裂技术攻关，实现威荣深层页岩气效益开发。

Compared to the middle and shallow strata, the engineering geological characteristics of Weirong deep shale gas are more complex, with the four characteristics of high ground stress, high horizontal stress difference, high plasticity, and high formation pressure. The complex engineering geological characteristics bring three major challenges: difficulty in forming complex fracture networks, difficulty in supporting and maintaining artificial fractures, and frequent occurrence of abnormal situations such as casing deformation. The specific performance result is the low single well EUR after gas well fracturing. Through unremitting exploration and practice, the fracturing technology has been continuously improved in the process of discovering and solving problems, and a series of measures of “fine optimization, real-time warning, operating pace control, and W-shaped well network” for preventing casing deformation and increasing post fracturing output has been formed based on the concept of balanced fracturing. The technology has been promoted and applied in 39 wells, and the fracturing effect has been continuously improved, with an average EUR increase of 500×104 m3 per well, and a decrease of casing deformation rate from 42.4% in 2022 to 16.67% at present. Due to the impact of the production of adjacent old wells on the production of newly fractured production wells, the output of new wells after fracturing is lower than the previous stage. With the existing well spacing of 400 m (Phase Ⅰ)/300 m (Phase Ⅱ), there is room for reduction and optimization in fracturing scale. Subsequent new wells should be differentiated and optimized based on remaining reserves, and research on fracturing technology shall be carried out continuously, achieving the beneficial development of Weirong deep shale gas.

中国石化“十条龙”科技攻关项目“威远—永川深层页岩气开发关键技术”(P18058)资助。

https://doi.org/10.11781/sysydz2023061143