煤炭工程 ›› 2024, Vol. 56 ›› Issue (2): 17-23.doi: 10.11799/ce202402003

• 设计技术 • 上一篇    下一篇

碎软低渗煤层水平井水力喷砂射孔工艺优化

张永成,赵祉友,汪奇,等   

  1. 1. 煤与煤层气实验室
    2. 煤与煤层气共采国家重点实验室
  • 收稿日期:2022-07-19 修回日期:2022-10-27 出版日期:2024-02-20 发布日期:2024-02-29
  • 通讯作者: 张永成 E-mail:79209071@qq.com

Optimization of hydraulic jet perforation technology in horizontal wells in broken and soft coal seam with low permeability

  • Received:2022-07-19 Revised:2022-10-27 Online:2024-02-20 Published:2024-02-29

摘要: 针对碎软低渗煤层水平井煤粉产出危害, 提出采用水力喷砂射孔压裂来实现“ 射孔-增透-控粉” 为一体的压裂改造理念, 具体工艺包含水力喷砂射孔、高压射流、环空压裂以及水力补射孔清洗。通过成本及工艺对比, 选择油管拖动水力喷砂射孔方式进行压裂, 并对工艺和关键工
具进行优化。首先, 优化防反冲蚀破坏一体化硬质合金圆锥收敛型喷嘴, 能实现排量2. 0 ~2. 5 m3 / min 时, 射流压力为16. 5~25. 8 MPa。其次, 优化喷射器本体, 能有效射穿套管、水泥塞,并射入岩石一定深度。配套一体化管柱顺利完成了煤层气U 型水平井压裂和补射孔施工各8 段, 每段射孔时间15 min 以上, 并充分顶替返排煤粉, 投产3 年后产气量仍达到3500 m3 / d 以上, 表明优化工艺达到了碎软低渗煤层改造效果。与连续油管分段压裂技术相比, 油管拖动水力喷射压裂单段压裂作业成本降低了28. 5%。

关键词: 碎软低渗煤层, 水平井, 水力喷砂射孔, 压裂

Abstract: Aiming at the harm of pulverized coal production in horizontal wells in broken soft and low permeability coal seams, A new concept of hydraulic jet perforation and fracturing is proposed,It can realize permeability enhancement and pulverized coal control,the specific processes include hydraulic jet perforation, high-pressure jet, annulus fracturing and hydraulic jet perforation cleaning.Through the comparison of cost and process, drag tubing hydraulic sand blasting perforation fracturing is selected, and the process and key tools are optimized. First, optimize the integrated cemented carbide conical convergent nozzle to prevent reverse erosion damage, which can achieve a jet pressure of 16.5-25.8MPa when the displacement is 2.0-2.5m3/min. Secondly, optimize the ejector body, which can effectively shoot through the casing and cement plug, and shoot into the rock to a certain depth. The supporting integrated string successfully completed the construction of 8-stage fracturing and 8-stage supplementary perforation of coalbed methane U-shaped horizontal well. The perforation time of each section is more than 15min, and fully displace the backflow pulverized coal, after three years of operation, the gas production still reaches more than 3500m3/d, it shows that the optimized process has achieved the transformation effect of broken soft and low permeability coal seams. Compared with coiled tubing staged fracturing technology,The single-stage fracturing operation cost through hydraulic jet fracturing by dragging tubing has been reduced by 28.5%.

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