Research On Oil And Gas Source And Accumulation Of Large-scale Carboniferous Volcanic Gas Fields In The Periphery Of Dishuiquan Sag, Junggar Basin

Some significant achievements have been made in the exploration of Carboniferous volcanic reservoirs in the periphery of the Dishuiquan sag,and the natural gas is rich.However,due to the irregular development and distribution of volcanic rocks in the area,there are some controversial about the source if oil and gas in the Carboniferous volcanic reservoirs and the formation process and accumulation methods of the reservoirs are not clear,which makes the related researches lagged behind.Therefore,based on the periphery of Dishuiquan depression of Carboniferous volcanic rock reservoir as the research object,it can make the spatial distribution of hydrocarbon source rocks and the hydrocarbon generating characteristics clearly.Based on the evaluation of the source rocks of different depression in this periphery,the hydrocarbon generation and accumulation process of typical Carboniferous volcanic reservoir are analyzed.Meanwhile,combined with the structural evolution and some characteristics of reservoirs and coverings,the model of accumulation will be established,which will lay the foundation for future exploration of volcanic oil and gas in this area.The B division of lower Carboniferous Songkaersu formation is the main stratum of Carboniferous source rocks,and there is a stable distribution.The type of source rocks featured a mixtured of marine and continental organic matter is varied with high abundance of organic matter,and it has high hydrocarbon production rate and strong hydrocarbon generation ability.The enrichment effect of organic matter by ash promoted the formation of high-quality source rocks,the transformation of source rocks to oil and gas are improved by the baking of igneous rocks and migration of transitional metals.The most important hydrocarbon production layer in Dishuiquan sag is in the Carboniferous by contrasting different conditions about the source rocks in different depression.The abundance of original material is better than any other layers,and the major type of original type is ?,which is influenced considerably by the volcanic movement.There are two kinds of key source rock in Dongdaohaizi-Wucaiwan sag:humic type carboniferous source rock and sapropel type Permian source rock.The Permian source rocks with the organic material of high abundance,good type and nature degree,which means that this kind of source rock has an excellent ability of oil supply.The typical Carboniferous volcanic gas field in the study area mainly consists of the KelameiliGas Fieldand the fault zone of the south.By the whole hydrocarbon geochemistry method,making the standard of features of source rock productions in different formations,it shows that Kelameili gas field and south fault step zone of Carboniferous oil and gas are mainly from Dishuiquan depression of Carboniferous source rocks.And there is no mixing of the sapropel type Permian source rock of the Dongdaohaizi depression.Study of reservoir showing:there are two period of hydrocarbon accumulation in the kelameili gas field,the first period is in the late Indo-China movement.Due to the different save conditions,the reservoirs are generally light reservoirs'.The second period is in the late Yanshanian movement,many well areas upward migration along the fault and form pure gas reservoir,which in the first hydrocarbon accumulation area.The oil in the Dishuiquan sag has been captured is in the mature stage,the natural gas is mainly in the high-over mature stage,and the oil and gas is moving from deep to shallow to the north and the south branches of the Dinan salient.Using the evolutionary features,this study will show that the allied but the asynchronous is the main reason for different types of Carboniferous oil and gas reservoirs in the kelameili gas field and the south belt fault order area.