超深层页岩气多域裂缝压裂实践

Practice of Multi-domain Fracture Fracturing in Ultra Deep Shale Gas

林永茂 缪尉杰 王兴文 慈建发 邓艺平 刘林 邱玲

LINYongmao MIAOWeijie WANGXingwen CIJianfa DENGYiping LIULin QIULing

中国石化西南油气分公司, 四川 成都 610000 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

Southwest Petroleum Branch, SINOPEC, Chengdu, Sichuan, 610000, China Petroleum Engineering Technology Institute of Southwest Petroleum Branch, SINOPEC, Deyang, Sichuan 618000, China

下寒武统筇竹寺组页岩气是继志留系龙马溪组页岩气后第二个具备大规模开发的页岩储层，资阳地区筇竹寺组普遍埋深大于4 500 m，部分超5 000 m，属于典型超深层页岩气储层。与龙马溪组深层页岩气压裂不同，筇竹寺组页岩气应力梯度高，大尺度裂缝欠发育，压裂面临超高压，低复杂裂缝的难点。针对以上难点攻关提出多域裂缝压裂提产技术，采用多手段精细刻画与微观岩性裂缝识别实现甜点中找蜜点，运用地震地质工程一体化软件开展全三维追踪裂缝扩展数值模拟，提出变密度分段分簇及依靠22 m$^3$/min排量沟通大尺度裂缝，基于物模复杂性实验，提出多重暂堵+停泵暂堵促进岩性微裂缝扩展，配套全域高强度裂缝构建的体积栅格柱塞工艺，突破超深层多类型多域裂缝沟通关与支撑关。该技术在ZY2井的成功运用实现超深层页岩气压裂的突破，压后获无阻流量306.42$\times$10$^4$ m$^3$/d，刷新深层、超深层页岩气产能纪录，有力保障了资阳地区筇竹寺组的勘探突破，为该区域超深层页岩气压裂工艺提供新思路。

The Lower Cambrian Qiongzhusi Formation shale gas is the second shale reservoir capable of large-scale development after the Silurian Longmaxi Formation shale gas. The Qiongzhusi Formation in Ziyang Area is generally buried at depths greater than 4 500 m, with some exceeding 5 000 m, and belongs to a typical ultra deep shale gas reservoir. Unlike the Longmaxi Formation's deep shale gas, the fracturing of Qiongzhusi Formation's shale is faced with difficulties of ultra high pressure and low complexity fractures due to its high stress gradient and under-developed large-scale fractures. This article proposes a multi domain fracture fracturing technology to address the above difficulties, based on geological multi-scale fracture identification and engineering corresponding fracture multi domain communication. By using multiple methods to finely characterize and identify micro lithological cracks, honey points can be found in sweet spots. Seismic-geological-engineering integrated simulation software carries out full 3D numerical modeling to track hydraulic fracturing propagation, and variable density segmented clustering and 22 m$^3$/min communication of wide area large-scale cracks are proposed. Based on the complexity experiment of the physical model, multiple temporary blockages+pump stop temporary blockages are proposed to promote the expansion of lithological microcracks, matched with 140 MPa and high-strength construction scale, breaking through the barrier and support of ultra deep, multi-type, and multi-domain crack channels. The successful application of this technology in Well ZY2 has achieved a breakthrough in ultra deep shale gas fracturing, creating multiple records in construction displacement, construction scale, and temporary plugging strength, effectively ensuring the exploration breakthrough of the Qiongzhusi Formation in Ziyang Area and providing new ideas for ultra deep shale gas fracturing technology in the region.

10.11885/j.issn.1674 5086.2024.11.26.01