家3-21X井仿生固壁钻井液技术

家3-21X井位于华北油田高家堡构造西北部家3断块,该井含有多个断层,在沙河街组含有大段盐膏层,出现过不同程度的井垮、井漏、缩径、电测遇阻甚至卡钻等复杂问题。为此提出了在原复合盐钻井液配方基础上引入仿生处理剂,以增强井壁稳定,同时添加NaCl,以抑制盐岩溶解的思路,并开展了室内配方优选和评价实验,形成了仿生固壁-复合盐钻井液体系。结果表明,该体系抑制性好,对复合盐岩屑的回收率高,其中盐膏岩的回收率达85%,膏泥岩的回收率达95%,较原体系明显提高;室内加入0.6% CaCl2污染,钻井液流变性能变化不大,综合性能易于调控。该体系在家3-21X井应用,井壁稳定效果好,平均井径扩大率降低幅度达62%,施工周期缩短。

Bionic Drilling Fluid Technology for Borehole Strengthening Used in Well Jia-3-21X

The Well Jia-3-21 X is located in the Jia-3 fault in the northwest of the Gaojiapu structure in Huabei Oilfield.The well penetrated several faults.The ShahejieFormation penetrated is consisted of long section of salt and gypsum interlayers.Borehole collapse, mud losses, tight hole and sticking of wireline logging tools and drill pipes have occurred during drilling operation.A bionic drilling fluid, capable of strengthening the borehole wall, was introduced to solve these problems.In laboratory studies, NaCl was introduced into the bionic drilling fluid to enhance its inhibitive capacity.Hot rolling test with salt rocks gave cutting recovery of 85%, and gypsum rocks gave cutting recovery of 95%.Contamination by 0.6% CaCl2, had only slight influence on the properties of the fluid.Field application of this drilling fluid on the Well Jia-3-21 X was very successful, with average hole enlargement decreased by 62%, and time of drilling greatly shortened.