Research on the Application of Expansion Pipe Patch Technology in Dagang Oilfield

At present, the casing failure injection wells in Dagang Oilfield account for 9.2% of the total number of oil and water wells in the oilfield, which affects the stable production and production increase of the oilfield. In view of this, the technological plan of using expansion pipe patch technology to repair the casing failure well was established. After having briefly introduced the principle of expansion pipe patch technology, the structural composition of patch tool string, the operation technology and the technological characteristics, this article carried out mechanical property test on the expansion pipe patch tubular goods, optimized high strength and low cost tubular goods 20G, used the multi-stage force-increasing cold drawing expansion forming process of ø139.7 mm casing to form large drift diameter expansion pipe patch technology, and subsequently carried out expansion pipe patch laboratory test. The test results show that the expansion pressure of the expansion pipe is 14～18 MPa, and the expansion rate of it is greater than 8.94%; the expansion pipe and the casing can withstand 500 kN tension without relative movement; the anchoring seal between the tubular goods and the casing is reliable, and the large drift diameter of the patch section is realized. This technology has been successfully applied in Well Jia47-7 of Dagang Oilfield, and the expansion pipe patch achieves the expected effect of plugging the leakage point of the pipe, which provides technical support and reference for the repair of casing failure injection wells in the oilfield.