高陡构造“三高、窄窗口”地层克深15井钻井液技术

克深15井是塔里木油田库车坳陷克拉苏构造带中段克深15号构造上部署的一口重点预探井,存在塔里木山前高陡构造、断层、大井眼、高温、高密度、高盐膏、窄密度窗口等工程、地质、钻井液技术难题。该井优选了抗高温高密度复合有机盐钻井液技术,围绕“低活度、弱水化、低的循环当量密度”等采取井壁稳定措施,通过现场实际应用,很好地解决了高陡构造、大倾角、破碎地层井壁稳定,大井眼安全快速钻进,盐膏层、盐膏泥混层阻卡、缩径,以及揭开盐层、盐膏层、目的层钻进窄密度窗口漏失等一系列技术难题,实现了全井安全无事故,多次电测均一次成功。与使用国外油基钻井液技术的邻井相比,钻井液实际应用密度降低0.05～0.08 g/cm3,体现了该体系强抑制、低的循环当量密度以及流变性良好,抗高温和抗盐、膏、泥等污染能力强,同时该体系无毒,环境保护性能好,无荧光,利于提高固井质量,低腐蚀,保护管串性能好等综合技术特性,并实现了钻井液、完井液一体化,提高了生产时效。该井的顺利完钻,进一步证明了抗高温高密度复合有机盐钻井液体系推广应用前景广阔。 

Drilling Fluid Technology for Well Keshen-15 Penetrating Highly Deep HTHP Gypsum Formations

The well Keshen-15 is a key exploration well drilled in the Keshen 15# structure of the middle Kelasu tectonic zone, Kuche depression, Tarim. Difficulties that must be faced during drilling include highly deep formations, faults, large hole size, high temperature, high mud density, developed salt and gypsum formations, and narrow mud density window etc. High temperature high density complex organic salt drilling fluids were formulated to have "low water activity, low hydrating potential and low equivalent circulation density (ECD)", in an effort to deal with the difficulties as mentioned above. With these measures, no trouble had ever occurred during drilling, and all of the wireline loggings were successful at the first try. Compared with the well drilled nearby with oil base drilling fluid, the mud density was reduced by 0.05-0.08 g/cm3, indicating that this organic salt drilling fluid had strong inhibitive capacity, low ECD, good rheology, high temperature stability, and resistance to salt, gypsum and drill cutting contamination. Meanwhile, this drilling fluid was environmentally friendly, non-fluorescent, had low corrosion to tubular goods, and can be used as drill-in fluid to save drilling time. The successful drilling of the well Keshen-15 has proved the potential of wide application of the high temperature high density complex organic salt drilling fluid.