A Study On Casing Patch Technology And Its Application

Liaohe Oilfield is a special oilfield whose major oil production is heavy oil which takes up 70% of the total reserves. One general meathod being used in production of heavy oil is steam soak.This technology can cause a considerable number of wells damaged, and therefore, resulting in well abandoned or stopping production, so the work on casing repair is getting more and more important.Casing patch is one of the important methods in casing repair. On the bases of further analyses to casing damage mechanism of thermal production wells and present status of casing patch technology both at home and abroad, considering the practice of casing patch in Liaohe Oilfield, the project presented here improved the packer structure of leakage identity and leakage inspection, improved packer rubber sheet quality, consummated leakage identity and leakage inspection technology prior and post casing patch, increased one time success percentage of leakage identity and leakage inspection.In the project,shaping technology of casing is further perfected,shaping tools preventing sticking and hydraulic shaping tools are manufactured, hydraulicly expandable tube casing patch tool is improved, and therefore, self-hangering casing patch tools are manufactured, which overcomes the shortcomings of unwilling packer setting when meeting resistance and unstable shear force of shear nails already existed in hydraulically expandable tube casing patch tool.The high temperature simulation test and well site application of self-hangering casing patch tools shows that the tools can meet the need of thermal production well casing patch in sealing and hangering.Further more, as for long length casing damage, a connecter tool with enough strength and maxmimunl inside diameter is manufactured, and well site operation procedure is summarized, realizing patch solidation with long length and large minimum inside diamiter. The achievement of the project has enriched and consummated casing patch technology, therefore, it supplies technical support for casing repair in Liaohe Oilfield.