Drilling Fluid Technology for Risk Exploration Wells in Qianshan, Kilometer Bridge

In order to explore the oil and gas in the Ordovician and Cambrian formations, Dagang Oilfield has deployed two risk exploration wells in the Kilometer Bridge exploration area. According to the data analysis of 22 wells drilled in this block, many sets of faults and interbedded sandstone and mudstone are encountered in the Shahejie Formation, and the risk of collapse is high. The Ordovician and Cambrian carbonate reservoirs have developed fractures and caves and high gas content. During the drilling process, leakage, collapse, narrow mud density window and circulating loss and kicking occurring at the same formations bring a series of challenges to the safe construction of drilling fluid. In view of the technical difficulties of drilling fluid, the drilling and completion data of the region are analyzed in detail. The bottom hole temperature is predicted by the formation temperature simulation technology, the density of the drilling fluid is accurately predicted by the three-pressure prediction, and the formula, temperature resistance, inhibitive capability, leakage prevention and plugging ability are optimized. It has been successfully implemented in two risk exploration wells, Well Qianqian 1 and Well Qianqian 2, and the construction of the two wells is smooth without complexity. It has created many records, such as the shortest drilling cycle of completed wells above 6000m in Dagang Oilfield, the deepest well depth in the Kilometer Bridge structure zone, the longest single drilling footage of the Ordovician system, and the highest machine speed, which is of great significance to the breakthrough of the new Cambrian strata and the scale of reservoir increase.