In the Songliao Basin,volcanic oil and gas reservoirs are important exploration domains.Based on drilling,logging,and 3D seismic(1495 km2)data,546 sets of measured physical properties and gas testing productivity of 6...In the Songliao Basin,volcanic oil and gas reservoirs are important exploration domains.Based on drilling,logging,and 3D seismic(1495 km2)data,546 sets of measured physical properties and gas testing productivity of 66 wells in the Changling fault depression,Songliao Basin,eruptive cycles and sub-lithofacies were distinguished after lithologic correction of the 19,384 m volcanic well intervals,so that a quantitative analysis was conducted on the relation between the eruptive cycles,lithologies and lithofacies and the distribution of effective reservoirs.After the relationship was established between lithologies,lithofacies&cycles and reservoir physical properties&oil and gas bearing situations,an analysis was conducted on the characteristics of volcanic reservoirs and the distribution rules of effective reservoirs.It is indicated that 10 eruptive cycles of 3 sections are totally developed in this area,and the effective reservoirs are mainly distributed at the top cycles of eruptive sequences,with those of the 1st and 3rd Members of Yingcheng Formation presenting the best reservoir properties.In this area,there are mainly 11 types of volcanic rocks,among which rhyolite,rhyolitic tuff,rhyolitic tuffo lava and rhyolitic volcanic breccia are the dominant lithologies of effective reservoirs.In the target area are mainly developed 4 volcanic lithofacies(11 sub-lithofacies),among which upper sub-lithofacies of effusive facies and thermal clastic sub-lithofacies of explosion lithofacies are predominant in effective reservoirs.There is an obvious corresponding relationship between the physical properties of volcanic reservoirs and the development degree of effective reservoirs.The distribution of effective reservoirs is controlled by reservoir physical properties,and the formation of effective reservoirs is influenced more by porosity than by permeability.It is concluded that deep volcanic gas exploration presents a good prospect in this area.展开更多
A large number of in-situ volcanic reservoirs have been discovered from the Meso-Cenozoic rift basin group in eastern China.Based on drilling results in combination with geological and geophysical analysis,a case stud...A large number of in-situ volcanic reservoirs have been discovered from the Meso-Cenozoic rift basin group in eastern China.Based on drilling results in combination with geological and geophysical analysis,a case study from the Early Cretaceous Xujiaweizi fault-depression shows that the formation mechanism of in-situ volcanic reservoirs is characterized by"fault-controlled body,body-controlled facies,facies-controlled reservoir,and reservoir-controlled accumulation".In other words,deep faults control the volcanic eruption type,volcanic body,and gas reservoir distribution;the volcanic body determines the spatial distribution of volcanic facies and volcanic gas reservoir size;the volcanic facies control reservoir physical properties and effective thickness of gas formation;the volcanic reservoir properties control gas reservoir type and gas productivity.The result is useful to guiding the discovery of in-situ volcanic gas reservoirs in faulted basins in both theory and practice.展开更多
文摘In the Songliao Basin,volcanic oil and gas reservoirs are important exploration domains.Based on drilling,logging,and 3D seismic(1495 km2)data,546 sets of measured physical properties and gas testing productivity of 66 wells in the Changling fault depression,Songliao Basin,eruptive cycles and sub-lithofacies were distinguished after lithologic correction of the 19,384 m volcanic well intervals,so that a quantitative analysis was conducted on the relation between the eruptive cycles,lithologies and lithofacies and the distribution of effective reservoirs.After the relationship was established between lithologies,lithofacies&cycles and reservoir physical properties&oil and gas bearing situations,an analysis was conducted on the characteristics of volcanic reservoirs and the distribution rules of effective reservoirs.It is indicated that 10 eruptive cycles of 3 sections are totally developed in this area,and the effective reservoirs are mainly distributed at the top cycles of eruptive sequences,with those of the 1st and 3rd Members of Yingcheng Formation presenting the best reservoir properties.In this area,there are mainly 11 types of volcanic rocks,among which rhyolite,rhyolitic tuff,rhyolitic tuffo lava and rhyolitic volcanic breccia are the dominant lithologies of effective reservoirs.In the target area are mainly developed 4 volcanic lithofacies(11 sub-lithofacies),among which upper sub-lithofacies of effusive facies and thermal clastic sub-lithofacies of explosion lithofacies are predominant in effective reservoirs.There is an obvious corresponding relationship between the physical properties of volcanic reservoirs and the development degree of effective reservoirs.The distribution of effective reservoirs is controlled by reservoir physical properties,and the formation of effective reservoirs is influenced more by porosity than by permeability.It is concluded that deep volcanic gas exploration presents a good prospect in this area.
基金supported by the National Basic Research Program of China(Grant No.2009CB219308)
文摘A large number of in-situ volcanic reservoirs have been discovered from the Meso-Cenozoic rift basin group in eastern China.Based on drilling results in combination with geological and geophysical analysis,a case study from the Early Cretaceous Xujiaweizi fault-depression shows that the formation mechanism of in-situ volcanic reservoirs is characterized by"fault-controlled body,body-controlled facies,facies-controlled reservoir,and reservoir-controlled accumulation".In other words,deep faults control the volcanic eruption type,volcanic body,and gas reservoir distribution;the volcanic body determines the spatial distribution of volcanic facies and volcanic gas reservoir size;the volcanic facies control reservoir physical properties and effective thickness of gas formation;the volcanic reservoir properties control gas reservoir type and gas productivity.The result is useful to guiding the discovery of in-situ volcanic gas reservoirs in faulted basins in both theory and practice.
