景谷凹陷钾盐地质调查JG-2井钻探施工技术

Drilling and construction technology of Well JG-2 of potash geological survey in Jinggu sag

摘要:

JG-2井是为进一步查明云南思茅盆地勐野井组钾盐资源而布置于景谷凹陷的调查井，地层岩性主要为泥岩、砂岩、泥砾岩和石盐等，在施工中存在井壁坍塌、缩径、钻头泥包、超径、岩心溶蚀、石盐矿层中机械钻速低、砂岩裂缝性漏失等问题。通过使用“无钾镁基饱和盐水钻井液”关键技术、改进钻头结构及使用PDC钻头、采用桥塞堵漏方法，较好地解决了岩心溶蚀、漏失、钻头泥包、钻探效率低等问题，最终完钻井深1829.44 m，完钻口径133 mm，盐层矿心采取率97.38%，取得了优质的钾石盐岩心和钻井质量。其施工技术经验可为以后同类工程提供借鉴。

Abstract:

Potassium salt mine is one of the minerals urgently needed in our country. JG-2 well is a geological data survey well arranged in Jinggu sag in order to further identify the potassium salt resources of Mengyejing Formation in Simao Basin， Yunnan Province. The formation lithology is mainly mudstone， sandstone， breccia and stone salt， etc. During the construction， the hydration expansion and spalling of mudstone and breccia caused the safety hazards of shaft wall collapse， diameter reduction and bit balling. Potassium salt rock layer is easy to dissolve， dissolution leads to super diameter， core dissolution， diamond bit in stone salt layer mechanical drilling rate is low， sandstone fracture leakage and other problems. By using the key technology of “Potassium-magnesium-based saturated brine drilling fluid”， improving the bit structure， using PDC bit and using bridge plug plugging method， the problems of core dissolution， leakage， bit balling and low drilling efficiency are better solved. The drilling depth is 1829.44m and the drilling diameter is 133mm. Salt bed core recovery rate of 97.38%， obtained high quality potassium rock core and drilling quality. This paper summarizes the technical experience and existing problems in the smooth implementation of JG-2 well， which can provide reference experience for similar projects in the future.