| Oil, as an important resource, plays an irreplaceable role in the national economy. The current development of wells with high pressure and low permeability has become an important growth point of recoverable reserves. But due to the particularity of reservoirs with high pressure and low permeability, it’s difficult and challenging to explore with testing tools and downhole strings, which brings out the need of optimization research for testing tools and downhole strings for reservoirs with high pressure and low permeability to ensure rationality and success of the operation. Based on the abovementioned reasons, this paper mainly talks about the string mechanics analysis and technology research for production in low permeability layer as follows:(1)we improved the structure of well test string conventionally used in the high pressure and low permeability wells, and developed some tools for the string.(2) we did mechanical analysis using the string mechanical analysis model established for the Wells test in high pressure low permeability wells, and obtained the conclusion that the string meet the strength requirement throughly in conditions such as setting, deblocking and fracturing.(3) we studied several low-costed draining techologies universally used in low permeability oil field and evently chose the jet pump draining technology.(4) we optimized cement slurry formulation for wells with HPHT and low permeability,and then we developed cementing technology for super deep wells. We optimized bridge plugging technology for HPHT difference, and then we developed combined technology of bridge plug and cement plug and achieve setting, sand-filling,cementing and detecting in one single string in order to plug the well permanently.(5)applying series of technology for wells with high pressure and low permeability into practice for verification for reasonability of string structure and design, we achieved the correctness of string mechanical analysis and feasibility of engineering process. |
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