成膜防塌无固相冲洗液在广西向阳坪地区复杂地层中的应用

Drilling fluid technology for complex formation drillingin the Xiangyangping area of Guangxi

摘要:

广西向阳坪地区地层复杂，存在多段大厚度水敏性蚀变地层及破碎地层，高岭石化及绿泥石化蚀变地层吸水后极易膨胀缩径或分散剥落，引起孔内掉块、孔壁坍塌等现象，导致卡钻、埋钻等孔内事故频发。通过对该地层岩心样品进行岩性分析，选择了成膜防塌无固相冲洗液体系，经过室内实验评价，确定了适用于向阳坪地区复杂地层的冲洗液配方，并在现场进行应用，有效地解决了水敏性蚀变地层吸水膨胀及分散剥落问题，护壁效果明显，孔壁稳定性显著提高，避免了孔内事故的发生，所取出的岩心完整且岩心采取率高，大大提高了钻进效率，缩短了施工时间，降低了施工成本。

Abstract:

The formation in the Xiangyangping area of Guangxi is complex. There are large sections of water-sensitive altered formation and broken formation. Kaolinite and chlorite altered formation is prone to expand and shrink or break off after water absorption, leading to frequent downhole incidents, such as rock falling, borehole collapsing, drilling string sticking or burial. Through the lithological analysis of the core samples from the formation, the film-forming anti-collapsing solid-free drilling fluid system was adopted, which effectively solved the expanding and shrinking problems of water-sensitive altered formation with remarkable enhancement of borehole wall stability and significant improvement of borehole wall protection. As a result, the cores taken out were intact with high core recovery; down-hole incidents were avoided; and drilling efficiency was greatly improved with shorter construction time and less construction cost.