Comprehensive Identification Of Volcanic Rocks And Reservoir Characteristics In Yingcheng Formation Of Dehui Fault Depression In Songliao Basin

The Dehui Fault Depression is located in the southeastern part of the Songliao Basin,and a large number of volcanic rocks are developed during the Mesozoic fault depression period.With the deepening of exploration and development of volcanic rocks in the basin,a series of achievements have been made in the study of volcanic rocks in the Dehui Fault Depression.However,compared with other areas in the Songliao Basin,there are still a series of problems,such as low research level.This paper takes Yingcheng Formation stratum as the target stratum.Based on the previous research,combined with logging and seismic data,the volcanic cycle and eruption period,volcanic eruption mode &identification,and volcanic mechanism are systematically carried out.The study aims to realize the characterization of the volcanic rocks of the Yingcheng Formation in the Dehui Fault Depression of the Songliao Basin.At the same time,combined with the microscopic and basic lithologic facies data and physical data,the reservoir space types and reservoir characteristics are analyzed.The main findings of this paper are as follows:1.The Yingcheng Formation of the Dehui fault depression can be divided into two sections,Ying1 and Ying 2,and the Ying1 section is a volcanic rock,which is the target horizon of this paper..The volcanic rock of the Yingcheng Formation can be divided into one cycles and three eruption period,one of which is dominated by Yingan rock,followed by volcanic clastic rocks such as rhyolite tuff and Anshan crystal tuff.The facies are dominated by the effusion phase,the second is the intrusive phase,the volcanic sedimentary facies and the explosive facies are less.2.Volcanic rocks in Dehui Fault Depression are divided into three types according to the type of eruption: the central eruption,fissure eruption and compound eruption;according to the scale of eruption,they are divided into small volcanic rock mass,medium volcanic rock mass and large volcanic rock mass.According to the internal cycle of volcanic rock mass,lithologic facies,and the same combination information of eruption,16 macroscopic geological models of the volcanic rocks of the Yingcheng Formation in Dehui fault depression were established in two dimensions: single well and continuous well.3.According to the characteristics of seismic reflection,eruption,lithology and flow unit stacking,the volcanic mechanism of Dehui fault depression can be divided into rhyolite lava volcanic mechanism,Ying'an lava volcanic mechanism,Anshan lava volcanic mechanism,Rhyolite clastic rock volcanic mechanism and Anshan clastic rock volcanic mechanism.4.The primary pores developed in this area are gravel pores;the secondary pores are devitrification pores and dissolution pores;the cracks are condensation shrinkage joints and gravel joints.Among them,secondary pores are the most developed in the matrix pores,and the reservoir performance is the best.The reservoirs in this area are mainly Ying'an rock reservoirs,tuff reservoirs and andesite reservoirs.The tuff reservoirs have the best reservoir effect,and the Ying'an rock reservoirs are easily replaced by later filling minerals.The effect is general,and the reservoir properties of andesite reservoirs are poor.5.The gas layer is distributed in the effluent phase,the explosive phase,the intrusion phase and the volcanic sedimentary facies,and the distribution is relatively uniform.The lithofacies cannot be the main way to determine the gas layer.The gas-water layer is mainly concentrated in the effusion phase,and there is a small amount in the volcanic sedimentary facies.The gas-bearing water layer is all distributed in the effusion phase,and the water layer is mainly concentrated in the intrusion phase.