According to China Petroleum News (reporter Li Shengmin), on April 28th, the pre-exploration well drilled by Bohai Drilling Company of Tarim Oilfield confirmed the drilling through the Permian igneous rock formation, which is 1579 meters long, from 5708 meters to 7287 meters, setting two records in China for the deepest drilling through and the longest section of the Permian igneous rock formation onshore, marking a new breakthrough in China's ultra-deep and ultra-thick Permian igneous rock formation drilling technology.
It is reported that the depth and thickness of the Permian igneous rock strata in this well are quite rare, and there are three sets of aquifers. There are many risks and problems such as strong abrasiveness, poor drillability, and instability of the wellbore. During the construction process, Tarim Drilling Branch implemented the "on-site + rear" two-level guarantee measures of technical experts through the EISC engineering operation intelligent support system, optimized drill bits and speed-increasing tools, and ensured the safe speed-increasing of the difficult-to-drill strata.
In view of the actual situation that the hardness of the Permian igneous rock strata increases gradually with the depth of the well, Tarim Drilling Branch insists on integrated construction of engineering geology, intensifies the identification and analysis of returned cuttings, and adjusts the drill bit selection and speed-increasing tool combination four times according to the degree of wear of the drill bit, and innovatively applies the "dumbbell-shaped" drill tool with two large ends and one small end in the middle, reducing the contact surface between the drill tool and the Permianey upper open-hole section, effectively reducing the risk of drill tool sticking, and the average mechanical drilling speed of Permian igneous rock strata reaches 1.43 meters/hour.
Currently, the Tarim Drilling Branch is organizing a technical team to start improving the speed-up technology template for ultra-deep and ultra-thick Permian igneous rock strata, providing strong technical support for the subsequent construction of similar wells in the Tarim Basin.