京津冀岩溶热储钻井关键技术

Key Technologies Involved in Karstic Geothermal Reservoir Drilling in the Beijing-Tianjin-Hebei Region

  • 摘要: 京津冀岩溶热储钻井存在以下技术难点:风化壳判断不准,易发生失返性漏失,导致垮塌埋钻;岩溶热储胶结差,取心收获率低;基岩储层非均质性强、可钻性差,钻头选型困难、机械钻速低。因此,利用XRF元素录井技术准确判断风化壳,防止风化壳发生失返性漏失,提高成井率;选用JS-6型全封销挂式多用取心筒与一体化岩心爪配合提高取心收获率;针对基岩储层的岩性和可钻性优选钻头型号和进行个性化设计,提高基岩储层的机械钻速;针对钻井过程易发生卡钻和漏失的问题,制定防卡和堵漏技术措施,最终形成了京津冀岩溶热储钻井关键技术。京津冀岩溶热储钻井应用该关键技术后成井率达到100%,钻井周期缩短10%以上,钻井成本降低12%。研究和实践表明,京津冀岩溶热储钻井关键技术可以解决京津冀岩溶热储钻井存在的技术难点,为京津冀地区地热资源的勘探开发提供技术支持。

     

    Abstract: Technical difficulties are encountered in the drilling of karstic geothermal reservoir in the Beijing-Tianjin-Hebei region. Lost circulation is frequent due to misjudgment of weathering crust, causing burial of drill bits induced by collapse; poor cementation of karstic geothermal reservoirs hinders core recovery; bedrock reservoirs present strong heterogeneity and poor drillability; bit selection requires much efforts and the rate of penetration (ROP) is low. Therefore, X-ray fluorescence (XRF) element logging has been used to accurately assess the weathering crust, so as to avoid lost circulation, and thus increase the well completion rate. The core recovery was improved by selecting JS-6 type fully-sealed pin-hanging multi-purpose coring barrel and an integrated core catcher, and the ROP was raised in bedrock reservoirs through optimal and customized design of bits based on the lithology and drillability of bedrock reservoirs. In order to solve the problems of sticking and lost circulation in the drilling process, corresponding technical measures were introduced, and finally the key technologies for karstic geothermal reservoir drilling in the Beijing-Tianjin-Hebei Region were developed. After applying these technologies, the well completion rate reaches 100% in the Beijing-Tianjin-Hebei Region. In addition, the drilling cycle is shortened by more than 10%, and the drilling cost is reduced by 12%. Research and practice showed that these key technologies can solve the problems of drilling in karstic geothermal reservoirs, and provide technical support for the exploration and development of geothermal resources in this region.

     

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