The distribution and treatment of harmful gas （H2S） in the Liaohe Oilfield, Northeast China, were investigated in this study. It was found that abundant toxic gas （H2S） is generated in thermal recovery of heavy oi...The distribution and treatment of harmful gas （H2S） in the Liaohe Oilfield, Northeast China, were investigated in this study. It was found that abundant toxic gas （H2S） is generated in thermal recovery of heavy oil. The H2S gas is mainly formed during thermochemical sulfate reduction （TSR） occurring in oil reservoirs or the thermal decomposition of sulfocompounds （TDS） in crude oil. H2S generation is controlled by thermal recovery time, temperature and the injected chemical compounds. The quantity of SO4^2- in the injected compounds is the most influencing factor for the rate of TSR reaction. Therefore, for prevention of H2S formation, periodic and effective monitoring should be undertaken and adequate H2S absorbent should also be provided during thermal recovery of heavy oil. The result suggests that great efforts should be made to reduce the SO4^2- source in heavy oil recovery, so as to restrain H2S generation in reservoirs. In situ burning or desulfurizer adsorption are suggested to reduce H2S levels. Prediction and prevention of H2S are important in heavy oil production. This will minimize environmental and human health risks, as well as equipment corrosion.展开更多
Beach-bars are well developed in the fourth member of the Shahejie Formation in the Shubei area, western depression of the Liaohe oilfield. The fourth member is composed of two three-order sequences, including a lower...Beach-bars are well developed in the fourth member of the Shahejie Formation in the Shubei area, western depression of the Liaohe oilfield. The fourth member is composed of two three-order sequences, including a lower Sequence 1（SQ1） and an upper Sequence 2（SQ2）. SQ2, which is the focus of this study, comprises a lowstand systems tract（LST） and a transgressive system tract（TST）. Three types of beach-bars have been recognized： shallow-littoral lacustrine sandy beach-bars, semi-deep lacustrine storm-related sandy beach-bars and shallow-littoral lacustrine carbonate beach-bars. Paleo-environments during the deposition of SQ2, including the paleo-geomorphology, paleo-water depth and paleo-source have been reconstructed to determine the formation mechanisms of the different types of beach-bars. The shallow-littoral lacustrine sandy beach-bars formed mainly by waves and currents and were mostly deposited in the LST, where water depths ranged from 3 to 9 m and the terrestrial clast supply is sufficient. The storm-related sandy beach-bars developed in the TST in the southern part of the study area near previously massively deposited sand bodies where there was sufficient water depth to preserve them. The carbonate beach-bars formed primarily in the TST in the Shubei low buried hill belt where there was a lack of terrestrial clast supply and complex, uneven geomorphology that easily gave rise to a lagoonal environment.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 4060201640773032)the National Basic Research Program of China (Contract No. 2007CB209500)
文摘The distribution and treatment of harmful gas （H2S） in the Liaohe Oilfield, Northeast China, were investigated in this study. It was found that abundant toxic gas （H2S） is generated in thermal recovery of heavy oil. The H2S gas is mainly formed during thermochemical sulfate reduction （TSR） occurring in oil reservoirs or the thermal decomposition of sulfocompounds （TDS） in crude oil. H2S generation is controlled by thermal recovery time, temperature and the injected chemical compounds. The quantity of SO4^2- in the injected compounds is the most influencing factor for the rate of TSR reaction. Therefore, for prevention of H2S formation, periodic and effective monitoring should be undertaken and adequate H2S absorbent should also be provided during thermal recovery of heavy oil. The result suggests that great efforts should be made to reduce the SO4^2- source in heavy oil recovery, so as to restrain H2S generation in reservoirs. In situ burning or desulfurizer adsorption are suggested to reduce H2S levels. Prediction and prevention of H2S are important in heavy oil production. This will minimize environmental and human health risks, as well as equipment corrosion.
基金supported by the China National Science and Technology Major Project (No. 2011ZX05009-002)
文摘Beach-bars are well developed in the fourth member of the Shahejie Formation in the Shubei area, western depression of the Liaohe oilfield. The fourth member is composed of two three-order sequences, including a lower Sequence 1（SQ1） and an upper Sequence 2（SQ2）. SQ2, which is the focus of this study, comprises a lowstand systems tract（LST） and a transgressive system tract（TST）. Three types of beach-bars have been recognized： shallow-littoral lacustrine sandy beach-bars, semi-deep lacustrine storm-related sandy beach-bars and shallow-littoral lacustrine carbonate beach-bars. Paleo-environments during the deposition of SQ2, including the paleo-geomorphology, paleo-water depth and paleo-source have been reconstructed to determine the formation mechanisms of the different types of beach-bars. The shallow-littoral lacustrine sandy beach-bars formed mainly by waves and currents and were mostly deposited in the LST, where water depths ranged from 3 to 9 m and the terrestrial clast supply is sufficient. The storm-related sandy beach-bars developed in the TST in the southern part of the study area near previously massively deposited sand bodies where there was sufficient water depth to preserve them. The carbonate beach-bars formed primarily in the TST in the Shubei low buried hill belt where there was a lack of terrestrial clast supply and complex, uneven geomorphology that easily gave rise to a lagoonal environment.
