Research on Key Technologies for Drilling Speed-Up of Ultra-deep Wells in the Kunteyi Block

In view of the technical challenges existing in the ultra-deep drilling process in the Kunteyi Block, such as the low rate of penetration (ROP) in the Jurassic-basement rocks, poor compatibility between the drill bit and the formation, limited application of speed-up tools, frequent occurrences of accidents and complexities like lost circulation, drill string failures, and long drilling cycles, aiming to achieve the efficient production of the Kunteyi Gas Field, starting from the formation lithology and drilling technical difficulties, through key technical research and applications including optimizing the wellbore structure, selecting high-efficiency drill bits, strengthening equipment parameters, optimizing the speed-up technology and drill string assembly, improving the inhibition and plugging properties of the drilling fluid, and wellbore cleaning analysis, an optimized and fast drilling technology for ultra-deep wells in the Kunteyi Block was developed. This technology was applied on-site in Well Kun 2-3 and Well Kun 2-4, with designed well depths of 7150 m and 7450 m respectively. Currently, the second-stage drilling has been completed. The average ROP is 14.87 m/h, which is 91.6% higher than the average ROP in the block. The results show that through the meticulous optimization of the plan, technical support can be provided for the new production capacity construction in the Kunteyi Block.