The detection and distribution of formation pressure with Fan simple method in Yingxiongling Area

In the Yingxiongling Area of Qaidam Basin, the formation pressure system is complicated in vertical, and the high pressure mechanism has not been made clear, which has brought a great challenge to the drilling work. To solve this problem, in this study, an advanced method with acoustic velocity-density crossplot has been used to analyze the abnormal formation pressure in the Yingxiongling Area of the Qaidam Basin. The results have shown that the abnormal high pressure in the Yingxiongling Area is mainly caused by the under-compaction, and is mainly concentrated in the layers form N22 to E32. According to the pressure mechanism, the Eaton method and the Fan simple method have been selected to calculate the formation pressure in the typical high-pressure wells in the Yingxiongling Area of Qaidam Basin. By comparing with the formation pressure control data, it has been found that the Fan simple method is more consistent with the actual situations and the accuracy is higher. With the Fan simple method, the vertical and lateral distribution of the formation pressure in the Yingxiongling Area have been obtained. The pressure distribution is consistent with the actual drilling conditions, which provides good guidance and reference for the smooth drilling of the Yingxiongling Area. The application results indicate that this method has a good prospect for promotion and application, laying a good foundation for next work.