Origin and quality evolution of volcanic reservoir in the Yingcheng Formation, Songliao Basin
Shao Hongmei1,2, Luo Jinglan3, Yang Yanfang3,4
1. China University of Geoscience, Beijing 100083;
2. Exploration and Development Research Institute, PetroChina Daqing Oil Field Company Ltd., Daqing 163712;
3. State Key Laboratory of Continental Dynamics, Northwest University, Xi'an 710069;
4. Test Institute of Shaanxi Geology and Mineral Resources, Xi'an 710054
Lithology of volcanic rocks and origin of volcanic reservoir from the Yingcheng Formation,Songliao Basin is studied,pore diagenetic evolution and forming mechanism is discussed in this paper,based upon the observation and description of drilled cores,the identification and quantitative statistics under microscope,analysis of major and trace element of whole rocks,the measurement of porosity and permeability,image pore throat of volcanic reservoir rocks,X-ray diffraction analysis for clay minerals,the determination of homogeneous temperature and chemical compositions and fluorescence of diagenetic liquid inclusions in volcanic rocks.This research is of great important theoretically and practically in understanding volcanic reservoir formation and origin,mechanism of volcanic reservoir pore evolution,impact parameters on volcanic reservoir quality,as well as in guiding hydrocarbon exploration and development and predicting prospect hydrocarbon reservoir areas.Research result shows that the four of cooling,post-magmatic hydrothermal,weathering leaching erosion and burial diagenetic phases occurred in the volcanic rocks.Formation,pore evolution and improvement of volcanic reservoir quality was closely related to faults and unconformity zones,developed structural fractures along which thermal liquids dissolved the easily dissolved materials thus resulted in developed secondary dissolution pores in the volcanic rocks during the late A stage of shallow burial(1500～2500 m)diagenetic phase to B stage of deep burial(>2 500～3 700 m)diagenetic phase.The volcanic gas-bearing pool is belong to structure-lithology controlled gas pool.