Fishing of the near-bit instrument in Well Jiaoye XX-HF

Abstract:

During the second stage development of Fuling Shale Gas, in order to detect formation changes in time, near-bit instruments were used in the first well planned on the drilling platform, so as to adjust the well trajectory in time and improve the intersection rate of high-quality shale. Placement of the near-bit instrument and the bit in front of the power tool will increase the load on the drive shaft of the power tool and easily lead to fatigue damage of the drive shaft. When Well Jiaoye XX-HF was drilled to 3971.42m, no signal was received from the near-bit instrument. After pulling out the drilling string, it was found that the driving shaft of the power drill tool broke off and the near-bit instrument and the bit were lost in the wellbore. The fish in this well was short and in the horizontal section; thus it was difficult to find the head of the fish. It was also difficult to determine whether the fishing tool touched the top of the fish by resistance due to the high friction. Through careful analysis of the fish, a feasible fishing plan was worked out, and the fishing box tap was processed on the spot. Finally, the fish was lifted out safely. The ideas and technical measures adopted in this well can be used for reference in dealing with similar accidents in the future.