丁页2HF页岩气水平井钻井技术

Drilling Technologies for Shale Gas Horizontal Well Dingye 2HF

丁页2HF井是部署在川东南丁山构造的一口页岩气水平井,目的层为志留系龙马溪组,设计井深5 655.00m。该井钻进中面临陆相地层厚度大、上部地层出水、气体钻井应用井段受限、地层可钻性差、钻头选型困难、长水平段托压严重、斜井段泥页岩井壁稳定性差等技术难点。为此,首先分析了丁山构造的工程地质特征;然后,结合邻区实钻资料,在钻进中综合应用了气体钻井、高效钻头优选、PDC钻头配合螺杆复合钻井、强封堵油基钻井液和漂浮下套管、三凝水泥浆体系等技术。实钻表明,这些技术的应用效果良好,不但使丁页2HF井顺利钻达目的层,而且完钻井深达到5 700.00m,创造当时国内页岩气水平井最深纪录。对该井应用的钻井技术和工艺及具体实施效果进行了分析,认为形成的丁页2HF页岩气水平井钻井技术,可为丁山构造页岩气水平井钻井提供参考。

Well Dingye 2HF is a horizontal well with the designed depth 5 655 mdrilled for shale gas in Silurian Formation in Dingshan Structure,southeastern Sichuan.There were several drilling challenges,such as extremely thick terrestrial formation,water production in upper formation,limited sections for gas drilling,poor drillability of formation,difficult in selecting bit type,not easy for putting weight on bit in long horizontal section,and poor stability of wellbore in deviated mud-shale section.Therefore,after investigating geological conditions of Dingshan Structure,and considering the drilling data of adjacent areas,Well Dingye 2HF was drilled by integrating several techniques,including gas drilling,efficient drill bit selection,PDC bit with PDM drilling,oil-based drilling fluids with plugging material,floated casing running,and 3-stage cementing slurry system.Practical operations proved good effects of such techniques,which allowed Well Dingye 2HF to penetrate successfully into the target layer,with total depth of 5 700 m,recording the deepest shale gas well in China.The drilling techniques,processes and results of Well Dingye 2HF was reviewed,and suggested that they could be valuable references for drilling other shale gas horizontal wells in Dingshan Structure.