直接返排钻开液在南海东部的应用

Application of Direct Flowback Drilling Fluid in the East of South China Sea

摘要: 针对海上油田水平井裸眼完井工艺复杂、作业繁琐及成本较高的问题，研究了直接返排钻开液体系。该体系配方简单，主要由改性黄原胶、改性淀粉及高纯粒径匹配碳酸钙组成，体系具有良好的储层保护性能，不需要破胶完井。该体系既节约成本又减少作业风险，并且在低渗透储层的应用效果也较好，目前已应用于南海东部9个油气田的29口井中，平均每口井完井作业时效节约9 h并节约费用60万元，取得了较好的成绩。

Abstract: In consideration of the problems of complicated technologies and complicated operation of open hole completion and high operation cost in offshore oilfields, a direct flowback system for drilling fluid was developed. The system was simple in formulation and it was composed of modified xanthan gum, modified starch and high purity calcium carbonate. The system had good reservoir protection performance and no need for gel breaking and completion. It not only saves costs, but also reduces operational risks. It can be used in the reservoirs with low permeability and it has good application effect. At present, it has been applied to 29 wells in 9 oil and gas fields in the eastern part of the South China Sea. Nine hours for completion in each well is saved in average and the cost is saved by 600000 Yuan RMB, and good results have been obtained.