A Transient Well Test Method for Wellhead Pressure Fall-Off Test After Acid Fracturing

Transient well test is an important method of identification technology of reservoir parameters including high-temperature and high-pressure ultra-deep well, deep well, high content of hydrogen sulfide and other complex well conditions. Requirements for testing equipment and process are more stringent, resulting in data acquisition difficulties. At the same time, the test needs to be stopped so that it affects production. A transient well test method for wellhead pressure fall-off test after acid fracturing is put forward. It is easier to obtain formation parameters and to improve the acquisition rate of formation test data. The pressure drop well test analysis involves analyzing the process of acid fracturing installation of high-precision electronic pressure gauge at the wellhead, the admission process of acid fracturing wellhead pressure and pump pressure after pressure drop data combined with the information of acid fracturing fluid injected into the wellbore flow. The well test interpretation results are basically consistent with the conventional pressure buildup test interpretation results, which can effectively evaluate the reservoir. The utility model does not need to insert any tool into the well shaft, thus avoiding the risk of downhole operation and saving the cost of the test capital.