煤层气大位移三维S型水平井分段浮法固井技术研究与应用

    Study and application of segmented floating cementing technology for large-displacement 3D S-shape horizontal well in coalbed methane

    • 摘要: 由于煤层储层条件差别大,水平段长度不断增加,复杂地质条件的煤层气水平井固井技术仍然存在一些缺陷,在固井施工方面的储层保护、套管下入与水泥浆注替工艺需要进一步改进,以提高固井质量,确保水平井后期的多级压裂安全性与工程质量。本文以保德煤矿为例,研究并提出了大位移三维S型煤层气水平井分段浮法与压力补偿法下套管工艺,优化出分级非均匀密度水泥浆体系,实施了低压耗顶替水泥浆的注浆工艺,形成了适宜于低压煤储层的固井配套技术。通过保德煤矿11号煤层的1L水平井成功应用,能够在大位移三维S型水平井将套管顺利下入井底,到达了保护煤储层的效果,确保了煤层气水平井的井筒完整性,为煤层气开发建立一个完善的井身结构。保德煤矿有多层高含气煤层,可以应用大位移三维S型水平井技术,以“井工厂”立体模式开发多层煤层气资源。

       

      Abstract: Due to significant variations in coal seam reservoir conditions and the continuous increase in horizontal wellbore lengths, cementing technology for coalbed methane(CBM) horizontal wells in complex geological environments still faces some challenges. Further improvements are required in reservoir protection during cementing operations, casing running, and cement slurry replacement processes to enhance cement quality and ensure safety and engineering integrity during multi-stage fracturing operations in later stages of horizontal well development. Taking Baode Coal Mine as a case study, this paper investigates and proposes a segmented floating method combined with pressure compensation casing runing technology for large-displacement 3D S-shaped coalbed methane horizontal wells. The research optimizes a graded non-uniform density cement slurry system and implements low-pressure displacement cement grouting techniques, ultimately developing cementing technologies suitable for low-pressure coal reservoirs. The successful implementation of a 1L horizontal well in the No.11 coal seam at Baode Coal Mine has demonstrated that large-displacement 3D S-shaped horizontal drilling technology enables secure casing running at the bottomhole, effectively protecting coal reservoirs while ensuring wellbore integrity in gas-bearing formations. This breakthrough establishes a perfect well structure for coalbed methane development. Baode Coal Mine’s multi-layered gas-rich coal seams make it ideal for applying this advanced drilling technique, allowing multi-layer gas resource development through the “well factory” integrated model.

       

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