姜政华,孙钢,陈士奎,等. 南川页岩气田超长水平段水平井钻井关键技术[J]. 石油钻探技术,2022, 50(5):20-26. DOI: 10.11911/syztjs.2022045
引用本文: 姜政华,孙钢,陈士奎,等. 南川页岩气田超长水平段水平井钻井关键技术[J]. 石油钻探技术,2022, 50(5):20-26. DOI: 10.11911/syztjs.2022045
JIANG Zhenghua, SUN Gang, CHEN Shikui, et al. Key drilling technologies for horizontal wells with ultra-long horizontal sections in Nanchuan Shale Gas Field [J]. Petroleum Drilling Techniques,2022, 50(5):20-26. DOI: 10.11911/syztjs.2022045
Citation: JIANG Zhenghua, SUN Gang, CHEN Shikui, et al. Key drilling technologies for horizontal wells with ultra-long horizontal sections in Nanchuan Shale Gas Field [J]. Petroleum Drilling Techniques,2022, 50(5):20-26. DOI: 10.11911/syztjs.2022045

南川页岩气田超长水平段水平井钻井关键技术

Key Drilling Technologies for Horizontal Wells with Ultra-Long Horizontal Sections in Nanchuan Shale Gas Field

  • 摘要: 南川常压页岩气田采用超长水平段水平井开发可提高其开发效益,但存在水平段极限延伸能力预测难、井眼轨迹控制难、井眼清洁效果差、钻柱摩阻扭矩大、套管下入难和固井易漏易气窜等技术挑战。为此,进行了管柱力学和流体力学分析,明确了超长水平段钻进和下套管时钻柱的受力状态,分析了超长水平段的水力延伸能力及关键影响因素。基于分析结果和南川页岩气田钻井实践,形成了井眼轨道优化设计、低成本高效导向钻井、井眼高效清洁、套管安全下入、超长水平段泡沫水泥浆固井等关键技术。上述技术在2口水平段长度超3 500 m的水平井进行了现场应用,全部使用国产的钻头、螺杆钻具及常规LWD,2口井平均钻井完井周期较设计缩短25.4%,实钻整体靶框控制在5 m以内,优质页岩钻遇率平均在90%以上,水平段复合钻进比例平均达90.45%,最大狗腿度0.15°/30m,高效成井的同时,实现了提速降本。南川页岩气田超长水平段水平井钻井关键技术,可为国内水平段长超3 500 m水平井的钻井提速提供借鉴。

     

    Abstract: The application of horizontal wells with ultra-long horizontal sections can improve the economic benefit of normal pressure shale gas in Nanchuan Shale Gas Field. However, there were many technical challenges with this technology, such as difficulties in predicting the ultimate extension capacity of horizontal sections and controlling wellbore trajectory, poor wellbore cleaning, large friction and torque, laborious casing running, frequent cementing leakage, and easy gas channeling, etc. Therefore, the pipe string mechanics and fluid mechanics were analyzed. Then, the force state of pipe strings during drilling and casing running in ultra-long horizontal sections was defined. Meanwhile, the hydraulic extension capacity of the ultra-long horizontal sections as well as the key influencing factors were analyzed. On the basis of the analysis results and drilling practices in Nanchuan Shale Gas Field, a group of key technologies were developed, such as wellbore trajectory optimization design, low-cost but efficient steering drilling, efficient wellbore cleaning, safe casing running, and foam cementing in ultra-long horizontal sections, etc. The above technologies were applied in two horizontal wells with horizontal section lengths exceeding 3 500 m. The whole drilling process was achieved by using drilling bits and positive displacement motors (PDMs) made in China as well as conventional logging while drilling (LWD). The average time for drilling and completion of the two wells was reduced by 25.4% compared with the design value, and the overall target frame of the actual drilling was controlled within 5 m. The encountering rate of high-quality shales and the compound drilling ratio in horizontal sections were above 90% and 90.45% on average, respectively. The maximum dogleg angle was 0.15°/30 m. It is not hard to see that the application of these technologies ensured efficient well construction while achieving increasing drilling speed and cost reduction. The key drilling technologies for horizontal wells with ultra-long horizontal sections in Nanchuan Shale Gas Field can provide a reference for speeding up the drilling of horizontal wells with a horizontal section length exceeding 3 500 m in China.

     

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