Characteristics And Evaluation Of Volcanic Reservoir In Dongling Area Of Songnan Gas Field

In the entire Songnan gas field,the volcanic rocks of the Yingcheng Formation in the Dongling area belong to the volcanic rocks outside the entire gas field.The oil and gas resources in this area are very rich,and the volcanic reservoirs are relatively well developed.On the other hand,due to the relatively wide distribution of volcanic rocks in this area,the differences between blocks are relatively large,which has a serious impact on the tectonic movement of the area,so the current understanding of volcanic rocks in this area is still Unclear,this severely restricts the optimization of target blocks in this area,and also has a serious impact on the next step of well deployment.In response to the above problems,this research first conducted a comprehensive collection and analysis of drilling,logging,seismic and related experimental data to understand the lithological characteristics of volcanic rocks in the Dongling area,so as to establish a framework for volcanic reservoirs.Observed by using cores,Nitrogen adsorption,scanning electron microscopy and other research methods to study the distribution of volcanic rock reservoirs in the Dongling area,clarify the formation mechanism of the reservoirs in the area,and use technical solutions such as drilling and logging to analyze the volcanic rock institutions and rocks in the Dongling area.The phase distribution is described,and the semi-quantitative evaluation and quantitative evaluation of volcanic reservoirs are finally completed.Through research,it is found that the lithology of volcanic rocks in the Dongling area is mainly intermediate-basic rocks with a small amount of acidic rocks.The Dongling area can be divided into three phases and six subfacies.In the Dongling area,the volcanic rocks are basically in the Yingcheng Formation,which can be divided into four eruption periods.Among them,there is only one eruption period in the upper part of Yingyi and three eruption periods in the lower part of the camp.The volcanic structures in the Dongling area can be divided into three types,namely the central land eruption type,the fractured land eruption type,and the fractured underwater eruption type.Reservoirs in the Dongling area can be divided into two types,namely weathered crust type reservoirs and inner type reservoirs.Among them,inner type reservoirs can be divided into plate lava flow type,composite lava flow type and vitreous Three types including clastic rock type.After semi-quantitative and quantitative evaluation of volcanic rock reservoirs in the Dongling area,it is found that the thickness,lithology,and fracture development of volcanic rock will have a serious impact on the reserves of weathered crust type reservoirs.The lithofacies and volcanic structures of volcanic rocks will It has a serious impact on the reserves of inner-type reservoirs.The evaluation results show that the weathering crust-type reservoirs in the Dongling area are mainly grade I and II,and they are basically located near the main fault.The inner-type reservoirs in the Dongling area are mainly Class III reservoirs are the main ones,with the least number of Class I reservoirs.This study has understood the basic characteristics of volcanic rock reservoirs in Dongling area,and conducted semi-quantitative and quantitative evaluations.The research results of this study can lay the foundation for further exploration of the potential of volcanic rocks in Dongling area.