In order to study the distribution of shale gas reservoir in the Babaoshan Basin of Eastern Kunlun,the wide-field electromagnetic(WFEM)survey was carried out to obtain the spatial distribution characteristics of the u...In order to study the distribution of shale gas reservoir in the Babaoshan Basin of Eastern Kunlun,the wide-field electromagnetic(WFEM)survey was carried out to obtain the spatial distribution characteristics of the underground electrical volume resistivity based on the delineation of the scope of the Babaoshan Basin by regional gravity data.The basic characteristics of the basement,basin framework,and extension,vertical change,burial depth of dark mud shale in this area were identified,and the electrical distribution of the Babaoshan mud shale horizon was revealed,which has been proved to be a good geological effect by drilling.The exploration results show that the WFEM has significant effects on the exploration of shale gas occurrence strata,which meets the needs of investigation and evaluation of multi-layered and large-scale shale gas,and plays a good demonstration role in the follow-up shale gas exploration.展开更多
The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casi...The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casings in steam-injection wells under different conditions, including steam channeling, well shut-in and cavitation in cement ring. The results indicate that nearly no temperature change occurs in oil-layer areas 4.0 m-6.0 m away from the casing center. When steam channeling appears, the maximum Mises stress of both the casing and the cement ring occurs on the interior wall. During the shut-in operation, while the maximum thermal expansion ocurs within the temperature-transition area, the maximum thermal stress will be on the interior wall of casing, exceeding the thermo-elastic yield ultimate stress of N80 steel. Besides, the thermal stress is much higher than the elastic strain limit if certain amounts of cavitations appear in the cement ring. Based on the results, some preventive measures against casing damage are proposed, which are verified through the successful application of TP120TH casings during well completion in Liao＇he oilfield.展开更多
基金Project(2019-SF-141)supported by Science and Technology Program of Qinghai Province,ChinaProjects(2017042105kc055,2017042014ky014)supported by Geological Exploration Foundation of Qinghai Province,China。
文摘In order to study the distribution of shale gas reservoir in the Babaoshan Basin of Eastern Kunlun,the wide-field electromagnetic(WFEM)survey was carried out to obtain the spatial distribution characteristics of the underground electrical volume resistivity based on the delineation of the scope of the Babaoshan Basin by regional gravity data.The basic characteristics of the basement,basin framework,and extension,vertical change,burial depth of dark mud shale in this area were identified,and the electrical distribution of the Babaoshan mud shale horizon was revealed,which has been proved to be a good geological effect by drilling.The exploration results show that the WFEM has significant effects on the exploration of shale gas occurrence strata,which meets the needs of investigation and evaluation of multi-layered and large-scale shale gas,and plays a good demonstration role in the follow-up shale gas exploration.
文摘The casing damage is a serious problem when the steam-injection method is applied in the oilfields. In this work, the commercial software ANSYS is used to predict the thermal expansion and the thermal stresses of casings in steam-injection wells under different conditions, including steam channeling, well shut-in and cavitation in cement ring. The results indicate that nearly no temperature change occurs in oil-layer areas 4.0 m-6.0 m away from the casing center. When steam channeling appears, the maximum Mises stress of both the casing and the cement ring occurs on the interior wall. During the shut-in operation, while the maximum thermal expansion ocurs within the temperature-transition area, the maximum thermal stress will be on the interior wall of casing, exceeding the thermo-elastic yield ultimate stress of N80 steel. Besides, the thermal stress is much higher than the elastic strain limit if certain amounts of cavitations appear in the cement ring. Based on the results, some preventive measures against casing damage are proposed, which are verified through the successful application of TP120TH casings during well completion in Liao＇he oilfield.
