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
The Liaohe Oilfield in the Liaohe Western Depression of the Bohai Gulf Basin is the third-largest oil producing province and the largest heavy oil producing oilfield in China. A total of 65 oil samples,35 rock samples...The Liaohe Oilfield in the Liaohe Western Depression of the Bohai Gulf Basin is the third-largest oil producing province and the largest heavy oil producing oilfield in China. A total of 65 oil samples,35 rock samples and 36 reservoir sandstone samples were collected and analyzed utilizing conventional geochemical and biogeochemical approaches to unravel the mechanisms of the formation of the heavy oils. Investigation of the oils with the lowest maturity compared with the oils in the Gaosheng and Niuxintuo oilfields indicates no apparent relation between the maturity and physical properties of the heavy oils. It is suggested that the heavy oil with primary origin is not likely the main mechanism re-sponsible for the majority of the heavy oils in the Liaohe Western Slope. The absence and/or depletion of n-alkanes etc.,with relatively low molecular weight and the occurrence of 25-norhopane series in the heavy oils as well as the relatively high acidity of the oils all suggest that the majority of the heavy oils once experienced secondary alteration. The fingerprints of the total scanning fluorescence (TSF) of the inner adsorbed hydrocarbons on the reservoir grains and the included hydrocarbons in fluid inclusions are similar to that of the normal oils in the area but are different from the outer adsorbed and reser-voired free oils at present,further indicating that most of the heavy oils are secondary in origin. Analyses of bacteria (microbes) in 7 oil samples indicate that anaerobic and hyperthermophilic Ar-chaeoglobus sp. are the dominant microbes relevant to oil biodegradation,which coincides with the shallow commercial gas reservoirs containing anaerobic bacteria derived gas in the Gaosheng and Leijia teotonic belts. The biodegradation most likely occurs at the water/oil interface,where the forma-tion water is essential for microbe removal and nutrient transportation. We think that biodegradation,water washing and oxidization are interrelated and are the main mechanisms for the formation of the heavy oils. Biodegradation was the predominant process with water washing being a prerequisite,and oxidization acting as a metabolic manifestation. This study provides unique approaches for further investigation of the formation mechanisms of heavy oils in general,and may provide some important insight for the exploration of shallow biogas in the area.展开更多
The Huanxiling oilfield is located in the southern part of the western slope of the western sag in Liaohe depression.The west side of this oilfield is connected with two sets of high-quality source rocks of Member 3 a...The Huanxiling oilfield is located in the southern part of the western slope of the western sag in Liaohe depression.The west side of this oilfield is connected with two sets of high-quality source rocks of Member 3 and Member 4 of Shahejie Formation in Qingshui sub-sag.The oilfield has fan delta,turbidite fan and other types of reservoirs,it also has cap rock of thick mudstone in Member 3 and Member 4 of Shahejie Formation.Under background of the warped basement,the warped fault-block draped compound trap zone are developed,which includes nine types of trap.From perspective of hydrocarbon accumulation,the slope of this area has always been the target area for hydrocarbon migration and accumulation.Inclusion analysis shows that there are multiple stages of hydrocarbon charging in this area,and the main reservoir forming period is the sedimentary period of Member 3 of Shahejie Formation and the sedimentary period of Dongying Formation.High-quality source-reservoir-cap conditions ensure large-scale hydrocarbon accumulation in this area.Based on the theory of compound hydrocarbon accumulation,many types of oil and gas reservoirs,including light oil reservoir and heavy oil reservoir,have been found in this area,with total reserves of 500 million tons.In view of the oilfield characterized by large reservoir burial span,multiple oil-bearing strata,strong heterogeneity and various types of oils,multi-batch seismic data processing&interpretation technology and thin reservoir inversion technology based on geological model are established in the preliminary exploration period,steam-flooding physical simulation technology of heavy oil,oil-reservoir fine description technology of thermal recovery heavy oil,steam huff and puff technology of ordinary heavy oil and steam-flooding technology of mid-deep buried heavy oil are developed in the development period,and technologies such as separate-layer injection,selective injection,sand control and lifting of heavy oil are matched and improved.These technology series provides technical guarantee for efficient exploration and development of Huanxiling oilfield.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 National Natural Science Foundation of China (Grant No.40772077/D0206)
文摘The Liaohe Oilfield in the Liaohe Western Depression of the Bohai Gulf Basin is the third-largest oil producing province and the largest heavy oil producing oilfield in China. A total of 65 oil samples,35 rock samples and 36 reservoir sandstone samples were collected and analyzed utilizing conventional geochemical and biogeochemical approaches to unravel the mechanisms of the formation of the heavy oils. Investigation of the oils with the lowest maturity compared with the oils in the Gaosheng and Niuxintuo oilfields indicates no apparent relation between the maturity and physical properties of the heavy oils. It is suggested that the heavy oil with primary origin is not likely the main mechanism re-sponsible for the majority of the heavy oils in the Liaohe Western Slope. The absence and/or depletion of n-alkanes etc.,with relatively low molecular weight and the occurrence of 25-norhopane series in the heavy oils as well as the relatively high acidity of the oils all suggest that the majority of the heavy oils once experienced secondary alteration. The fingerprints of the total scanning fluorescence (TSF) of the inner adsorbed hydrocarbons on the reservoir grains and the included hydrocarbons in fluid inclusions are similar to that of the normal oils in the area but are different from the outer adsorbed and reser-voired free oils at present,further indicating that most of the heavy oils are secondary in origin. Analyses of bacteria (microbes) in 7 oil samples indicate that anaerobic and hyperthermophilic Ar-chaeoglobus sp. are the dominant microbes relevant to oil biodegradation,which coincides with the shallow commercial gas reservoirs containing anaerobic bacteria derived gas in the Gaosheng and Leijia teotonic belts. The biodegradation most likely occurs at the water/oil interface,where the forma-tion water is essential for microbe removal and nutrient transportation. We think that biodegradation,water washing and oxidization are interrelated and are the main mechanisms for the formation of the heavy oils. Biodegradation was the predominant process with water washing being a prerequisite,and oxidization acting as a metabolic manifestation. This study provides unique approaches for further investigation of the formation mechanisms of heavy oils in general,and may provide some important insight for the exploration of shallow biogas in the area.
基金supported by the National Science and Technology Major Project of China(No.2011ZX05006-005)。
文摘The Huanxiling oilfield is located in the southern part of the western slope of the western sag in Liaohe depression.The west side of this oilfield is connected with two sets of high-quality source rocks of Member 3 and Member 4 of Shahejie Formation in Qingshui sub-sag.The oilfield has fan delta,turbidite fan and other types of reservoirs,it also has cap rock of thick mudstone in Member 3 and Member 4 of Shahejie Formation.Under background of the warped basement,the warped fault-block draped compound trap zone are developed,which includes nine types of trap.From perspective of hydrocarbon accumulation,the slope of this area has always been the target area for hydrocarbon migration and accumulation.Inclusion analysis shows that there are multiple stages of hydrocarbon charging in this area,and the main reservoir forming period is the sedimentary period of Member 3 of Shahejie Formation and the sedimentary period of Dongying Formation.High-quality source-reservoir-cap conditions ensure large-scale hydrocarbon accumulation in this area.Based on the theory of compound hydrocarbon accumulation,many types of oil and gas reservoirs,including light oil reservoir and heavy oil reservoir,have been found in this area,with total reserves of 500 million tons.In view of the oilfield characterized by large reservoir burial span,multiple oil-bearing strata,strong heterogeneity and various types of oils,multi-batch seismic data processing&interpretation technology and thin reservoir inversion technology based on geological model are established in the preliminary exploration period,steam-flooding physical simulation technology of heavy oil,oil-reservoir fine description technology of thermal recovery heavy oil,steam huff and puff technology of ordinary heavy oil and steam-flooding technology of mid-deep buried heavy oil are developed in the development period,and technologies such as separate-layer injection,selective injection,sand control and lifting of heavy oil are matched and improved.These technology series provides technical guarantee for efficient exploration and development of Huanxiling oilfield.
