适于生物酶破胶的新型水平井钻开液体系

在水平井钻完井作业中。要求先前的钻开液能与后续的破胶技术相匹配．考虑到现场的安全因素．有必要对现有的无固相钻开液体系进行改进。采用新型的增粘剂代替原有的XC增粘剂，试验结果显示，新型增粘剂加量为0．7％时能满足对流变性的要求；通过对钻开液体系中的添加剂进行评价和筛选，得出2％的降滤失剂能有效控制失水。2％的润滑剂降摩阻率可以达到72．1％，最终得到新型钻开液的配方为：海水＋0．7％PF-VIS-1＋2％DFD十0．25％Na2CO3＋3％KCl＋2％HLX。该体系对JBR生物破胶剂十分敏感，在加量达到0．2％时，破胶率就达到90％以上。破胶效果好。

A New Horizontal Well Drilling Fluid System Suitable for Enzyme Demulsification

In the completion of horizontal wells, previous drilling fluid should be matched with consequent demulsification technique, in consideration of safety factors, solid-free drilling fluid system must be improved. A new viscosifier is used to replace the original XC viscosifier. The test result shows it can satisfy the needs of rheology when the addition of new viscosifier is 0.7%; after additive to the drilling fluid system is evaluated and selected, 2% fluid loss additive is selected to control water loss effectively, 2% lubricant is used to achieve 72.1% of friction reduction. Finally, the new drilling fluid formula, including sea water+0.7%PF-VIS-1+2%DFD+0.25%Na_2CO_3+3%KCl+2%HLX is determined. This system is sensitive to JBR biological enzyme breaker, when the dosage is 0.2%, break rate is above 90%, and break effect is good.