Where are the zones more enriched in sand deposits in the down slope and deep depression of the low swelling slope belt? Are there any screening conditions for oil and gas there? These are the chief geological problem...Where are the zones more enriched in sand deposits in the down slope and deep depression of the low swelling slope belt? Are there any screening conditions for oil and gas there? These are the chief geological problems to be solved during exploration of a region. Taking the Paleogene system developed along the east slope belt of Chengdao as an example the concepts of sequence stratigraphy and sedimentary sequenc are applied. A new research method likened to a way ''to get a melon by following the vine'' is proposed to determine the direction for exploring within un-drilled or less-drilled areas. This is the process: ''the characteristics of the sequence boundary ? the forming mechanism of the stratigraphic sequence ? the conditions of oil and gas accumulation ? the distribution zones of oil and gas''. The relationship between the dynamic mechanism of stratigraphic sequence and the forming conditions for oil and gas accumulation establishes that the tectonic disturbance of the slope belt has significant responses as denudation and deposition. Above the stratigraphic sequence boundary there are large scale sand bodies of the low stand system tract (LST) that have developed in the low swelling slope belt and its deep depression. Below the sequence boundary there are the remaining sand bodies of the high stand system tract (HST). On the slope there is a convergence of mudstone layers of the extended system tract (EST) with the mudstone of the underlying strata, which constitutes the screening conditions for the reservoir of the down slope and deep depression. The distribution regularities in preferred sand bodies on the surface of the sequence boundary, and in the system tract, indicate the ordering of oil-gas deposits. From the higher stand down to the depth of the slope there are, in order, areas where exploration was unfavorable, major areas of stratigraphic overlap of oil-gas reservoirs, unconformity screened oil-gas reservoirs, and, finally, sandstone lens oil-gas reservoirs. The low swelling slope belt of Chengdao was tectonically active, which is typical for a continental rift basin. The methodology and results of the present paper are significant for the theory and practice of predicting subtle reservoir and selecting strategic areas for exploration.展开更多
In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane （CBM） reservoir formations, the eff...In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane （CBM） reservoir formations, the effect of hydrodynamic forces controlling CBM reservoir formations was studied by a physical simulation experiment in which we used CBM reservoir simulation facilities. The hydrodynamic conditions of high coal rank reservoirs in the Qinshui basin were analyzed. Our experiment shows the following results： under strong hydrodynamic alternating action, 6C~ of coalbed methane reservoir changed from the start at -2.95% ~ -3.66%, and the lightening process occurred in phases; the CI-I4 volume reduced from 96.35% to 12.42%; the CO2 vo- lume decreased from 0.75% in sample 1 to 0.68% in sample 2, then rose to 1.13% in sample 3; the N2 volume changed from 2.9% in sample 1 to 86.45% in sample 3. On one hand, these changes show the complexity of CBM reservoir formation; on the other hand, they indicate that strong hydrodynamic actions have an unfavorable impact on CBM reservoir formation. It was found that the gas volume and hydrodynamic intensity were negatively correlated and low hydrodynamic flow conditions might result in highly productive and enriched areas of high rank CBM.展开更多
We investigated the geological factors associated with unsuccessful exploration wells in the northern margin of the Qaidam basin to better understand their cause.The structural situation,the hydrocarbon accumulation m...We investigated the geological factors associated with unsuccessful exploration wells in the northern margin of the Qaidam basin to better understand their cause.The structural situation,the hydrocarbon accumulation mechanism and unsuccessful well data collected from 1996 to 2005 were studied.The results show that the main geological factors associated with unsuccessful exploration wells are a lack of effective source rocks and a lack of effective traps,as well as the migration-accumulation conditions that exist in this area.The basin was reformed by Meso-Cenozoic tectonic evolution.Multi-stage tectonic activities have both positive and negative effects on hydrocarbon accumulation.Source rocks distribution,effective migration channels,effective traps and the tectonic evolution effects on hydrocarbons should be the key objects for further studies.展开更多
The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is st...The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is still rarely reported. In this study, a quantitative research method for tectonization intensity is proposed. The research result on Tahe-Lunnan oilfield shows that this method can not only quantitatively express the tectonization intensity, but also qualitatively reflect the macroscopic deform property and the evolution history of strata. Therefore, it is an effective method for analyzing the characteristics of tectonization. In addition, the realization of the method also can provide qualitative information for studying the influence and control of tectonization on hydrocarbon accumulation.展开更多
基金The present paper is a part of the research work of the post-doc program: ''The Research on the Genesis of Paleogene Sand Bodies in the Chengdao East Slope and Its Controlling Factors'' (No.YKB 0804)
文摘Where are the zones more enriched in sand deposits in the down slope and deep depression of the low swelling slope belt? Are there any screening conditions for oil and gas there? These are the chief geological problems to be solved during exploration of a region. Taking the Paleogene system developed along the east slope belt of Chengdao as an example the concepts of sequence stratigraphy and sedimentary sequenc are applied. A new research method likened to a way ''to get a melon by following the vine'' is proposed to determine the direction for exploring within un-drilled or less-drilled areas. This is the process: ''the characteristics of the sequence boundary ? the forming mechanism of the stratigraphic sequence ? the conditions of oil and gas accumulation ? the distribution zones of oil and gas''. The relationship between the dynamic mechanism of stratigraphic sequence and the forming conditions for oil and gas accumulation establishes that the tectonic disturbance of the slope belt has significant responses as denudation and deposition. Above the stratigraphic sequence boundary there are large scale sand bodies of the low stand system tract (LST) that have developed in the low swelling slope belt and its deep depression. Below the sequence boundary there are the remaining sand bodies of the high stand system tract (HST). On the slope there is a convergence of mudstone layers of the extended system tract (EST) with the mudstone of the underlying strata, which constitutes the screening conditions for the reservoir of the down slope and deep depression. The distribution regularities in preferred sand bodies on the surface of the sequence boundary, and in the system tract, indicate the ordering of oil-gas deposits. From the higher stand down to the depth of the slope there are, in order, areas where exploration was unfavorable, major areas of stratigraphic overlap of oil-gas reservoirs, unconformity screened oil-gas reservoirs, and, finally, sandstone lens oil-gas reservoirs. The low swelling slope belt of Chengdao was tectonically active, which is typical for a continental rift basin. The methodology and results of the present paper are significant for the theory and practice of predicting subtle reservoir and selecting strategic areas for exploration.
基金Project 2002CB211705 supported by the National Basic Research Program of China
文摘In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane （CBM） reservoir formations, the effect of hydrodynamic forces controlling CBM reservoir formations was studied by a physical simulation experiment in which we used CBM reservoir simulation facilities. The hydrodynamic conditions of high coal rank reservoirs in the Qinshui basin were analyzed. Our experiment shows the following results： under strong hydrodynamic alternating action, 6C~ of coalbed methane reservoir changed from the start at -2.95% ~ -3.66%, and the lightening process occurred in phases; the CI-I4 volume reduced from 96.35% to 12.42%; the CO2 vo- lume decreased from 0.75% in sample 1 to 0.68% in sample 2, then rose to 1.13% in sample 3; the N2 volume changed from 2.9% in sample 1 to 86.45% in sample 3. On one hand, these changes show the complexity of CBM reservoir formation; on the other hand, they indicate that strong hydrodynamic actions have an unfavorable impact on CBM reservoir formation. It was found that the gas volume and hydrodynamic intensity were negatively correlated and low hydrodynamic flow conditions might result in highly productive and enriched areas of high rank CBM.
基金Project XQ-2004-01 supported by the National Oil Project of China
文摘We investigated the geological factors associated with unsuccessful exploration wells in the northern margin of the Qaidam basin to better understand their cause.The structural situation,the hydrocarbon accumulation mechanism and unsuccessful well data collected from 1996 to 2005 were studied.The results show that the main geological factors associated with unsuccessful exploration wells are a lack of effective source rocks and a lack of effective traps,as well as the migration-accumulation conditions that exist in this area.The basin was reformed by Meso-Cenozoic tectonic evolution.Multi-stage tectonic activities have both positive and negative effects on hydrocarbon accumulation.Source rocks distribution,effective migration channels,effective traps and the tectonic evolution effects on hydrocarbons should be the key objects for further studies.
基金Supported by China Postdoctoral Science Fund (Grant No.2012M510714)
文摘The research on tectonization intensity plays an important role in the analyses of basin evolution and hydrocarbon accumulation. At present, methods in this field are almost qualitative, and the quantitative one is still rarely reported. In this study, a quantitative research method for tectonization intensity is proposed. The research result on Tahe-Lunnan oilfield shows that this method can not only quantitatively express the tectonization intensity, but also qualitatively reflect the macroscopic deform property and the evolution history of strata. Therefore, it is an effective method for analyzing the characteristics of tectonization. In addition, the realization of the method also can provide qualitative information for studying the influence and control of tectonization on hydrocarbon accumulation.
