塔河地区超深中生界井壁稳定钻井液技术OA

In view of the problems such as wellbore instability and pipe sticking and drags encountered in drilling the Triassic and Carboniferous formations in several wells in the Tahe area,geological research,drilling fluid measures,optimization study and field application of the research results were carried out.It was found in the studies that the clay mineral content of the Triassic and Carboniferous formation is 35.2%to 44.3%,mainly illite and illite/smectite mixed layers.The micropores of the formation are interconnected,and the strength of the formation on the borehole wall is attenuated due to hydration,which in turn induces problems such as wellbore instability and pipe sticking and drags encountered.After combining the actual conditions of on-site engineering,the study found that strengthening the wall-fixing performance of drilling fluid is necessary.Therefore,based on field drilling fluid,one conducted laboratory optimization and developed chemo-mechanical coupling drilling fluid suitable for Triassic and Carboniferous formations.Field application indicates that the borehole enlargement rate using the optimized drilling fluid system is 30%,while the maximum borehole enlargement rate exceeded 100%with the pre-optimization drilling fluid system.The significantly reduced borehole enlargement rate demonstrates the effectiveness of the optimized drilling fluid system.