Stratigraphic Pressure And Leakage Pressure In The Western Part Of Hero Ridge In Qaidam Basin

The western region of Hero Ridge(abbreviated as yingxi region)is located in the northwestern end of the Qaidam Basin in the heroic ridge tectonic belt of the western depression area,where faults and cracks have developed,with a large number of layers of paste salt,long layers,and complex geological structures.The ability of regional formations to withstand pressure is low,and complex situations such as well leakage often occur;its pressure system in the longitudinal direction is also very complex,and there are high-pressure brine layers with unclear layers,which often occur complex accidents such as overflow and well leakage due to the high unpredictability of the drilling process.Aiming at the complex working conditions in The British and Western Regions,this paper clarifies the pore pressure and leakage pressure of the formation in the region by deepening the understanding of the genesis mechanism of abnormal high pressure in the Yingxi region,the calculation model of the formation pore pressure and the formation leakage pressure in the preferred area,and determines the safe drilling fluid density window to provide technical support for the safe drilling in the Yingxi region.In this paper,by collecting the logging and logging data of the wells that have been drilled,the acoustic wave velocity-density intersection map of each well is drawn,which is used as a basis to judge the abnormal high-pressure genesis mechanism of the formation in this area;the appropriate formation pore pressure calculation model is optimized for the high-pressure genesis mechanism obtained by the analysis combined with the geological conditions of the area,and the pore pressure results of the drilled formation are calculated by the model,and the pore pressure status of the formation in the region is further clarified;the formation leakage mechanism in the Yingxi region is judged by imaging logging and core analysis.A suitable formation leakage pressure calculation model is selected,and the result of the formation leakage pressure of the drilled wells in the region is calculated through the model,and the safe drilling fluid density window is determined.Through research,analysis and calculation,the cause mechanism of abnormal high pressure in The Yingxi region is mainly under-compaction,and the formation pore pressure calculation model of the Fan comprehensive interpretation method is optimized through calculation and comparison,and according to the measured data,the model parameters of the drilled well are determined,the pore pressure calculation model of the drilled formation is obtained,and the pore pressure result of the drilled formation is obtained through the model calculation;the fracture structure of the Drilled Formation is analyzed and understood.Through imaging logging and rock data analysis,the leakage mechanism in The Yingxi region is mainly based on fissile natural leakage,supplemented by induced fracture leakage.The fractured leakage pressure dynamic model is optimized,and the parameters of the model are determined according to the measured data,and the calculation model of the drilled formation leakage pressure is obtained,and the result of the drilled formation leakage pressure is calculated through the model,and the safe drilling fluid density window is determined.