南苏丹A油田KCl/硅酸盐钻井液体系的评价与优选

EVALUATION AND OPTIMIZATION OF KCL/SILICATE DRILLING FLUID SYSTEM FOR A OILFIELD OF SOUTH SUDAN

南苏丹A油田钻井数据统计表明,该油田钻井复杂发生率高达40%,主要表现为缩径卡钻、井壁坍塌和井漏等,而且取心收获率较低,有的井甚至无法完成测井作业。针对这种情况,优选了一种新型KCl/硅酸盐钻井液体系。该体系在抑制性、润滑性及抗污染等方面均表现出良好性能,现场应用结果表明,新型钻井液体系可以有效防止井塌和缩径,保持井壁稳定,同时可以保护储层,提高储层的渗透率,有效控制了钻井复杂及事故的发生。

The drilling data statistics of A oilfield in South Sudan showed that the downhole accident rate reached as high as 40%,mainly including bit freezing,holewall collapsing,lost circulation and so on,and core recovery was lower,sometimes even couldn't complete logging operation.In view of this situation,a new KCl/silicate drilling fluid system was optimized.This system has good performance,such as inhibitive characteristic,lubricity and anticontamination.Field application showed that the new drilling fluid system could effectively pre-vent wellhole sloughing,keep wellhole stability,protect reservoir and improve reservoir permeability,and effectively control the drilling accidents.