Ultimate Life Prediction and Safety Control of Injection-Production String for Water Flooding of Heavy Oil Reservoir
Long-term water injection in some heavy oil fields in China,has caused integrity issues in the pipe strings.The residual strength of existing N80 and J55 carbon steel tubing after corrosion fails to meet the require-ments,and piercing and breaking of the string occur from time to time.In order to determine the timing of repla-cing the strings in injection and production wells,based on the CO2 and O2 corrosion prediction models,a predic-tion method for corrosion of tubing and casing in injection and production wells was established.Then,the injec-tion and production wells in an oilfield of the Bohai Sea were selected to verify the applicability and reliability of the calculation method.Referring to API 5C3,a string strength calculation method considering corrosion was estab-lished.Thus,a method for predicting the ultimate life of tubing and casing was obtained.Finally,these methods were applied in injection and production wells of the Bohai Sea area respectively,and some safety control sugges-tions were proposed.The results show that the average errors between corrosion prediction results and test data of injection and production wells are 5.27%and 11.37%respectively,suggesting a satisfactory applicability.The safe service time of injection wells and dissolved oxygen concentration safety control values are determined.The re-search results effectively guide the timing of replacing string in water flooding heavy oil wells and reasonable control of injection water quality,and provide theoretical support for extending the service life of old wells and ensuring safe and efficient operation of injection and production wells.
heavy oil injection wellinjection-production stringcorrosionlife predictionsafety control
NETL
NSTL
万方数据
维普
