Study on core stress sensitivity for gas reservoir with two experiment method

Core stress sensitivity test in lab generally uses the change outside pressure and keep inside pressure test method at present, which is not in accordance with actual gas field development process that overburden pressure does not change while fluid pressure decreases. This paper puts forward the change inside pressure and keep outside pressure test method and use Sulige gas field low permeability core do the change outside pressure and keep inside pressure test and change inside pressure and keep outside pressure test at the condition of formation temperature. Study results indicate that the core stress sensitivity of change inside pressure and keep outside pressure test is little than that of change outside pressure and keep inside pressure test, core stress sensitivity become more little even tend to a limit with multiple stress sensitivity times. This provides experiment accordance for gas well dynamic analysis and has very important meaning for study on stress sensitivity character of low permeability gas reservoir relative high , medium , low permeability core during multiple stress rise and drop process.