Research On Logging Evaluation Method Of Carboniferous Volcanic Reservoir In Santanghu Basin

The Carboniferous in the Santanghu Basin is mainly composed of volcanic rocks.Due to the particularity of volcanic rocks,there are many problems in the oil and gas exploration process: the volcanic lithology is complex and variable,Hydrothermal alteration causes reservoir space influencing factors and reservoir conductivity mechanism to be complex,which indirectly leads to difficulties in reservoir physical property calculation,reservoir classification difficulties,and fluid identification difficulties.In view of the above problems,based on logging data,this paper comprehensively utilizes core,logging,full-rock X-ray diffraction quantitative analysis,oil test and electrical imaging,nuclear magnetic,array acoustic wave and other data to determine the lithology and alteration degree of volcanic rocks.The main alteration type of Carboniferous is determined by clay sheet and full-rock X-ray scanning.The volcanic lava and volcanic clastic rocks of Karagang Formation are scaled by three porosity curves,Hargawu.The group of volcanic lavas uses the neutron curve and the resistivity curve to scale the degree of alteration,and analyzes the law of physical properties changing with the degree of alteration.According to the established classification criteria of alteration degree,the matrix porosity model with different degrees of alteration is established,and the calculation effect is better.Cracks were identified and evaluated for effectiveness using conventional logging data,array acoustic waves,and electrical imaging.The fracture porosity was calculated by using electrical imaging data and dual lateral data respectively.It was found that the effect of calculating the fracture porosity of the two lateral data is poor.Therefore,the fracture porosity is mainly determined by electrical imaging data,and the Doll formula,the Poupon formula and the empirical formula are used respectively.Water saturation of reservoirs with different resistivity.According to the different types of volcanic rock reservoirs,the volcanic lava and volcanic clastic reservoirs in the Karagang Formation depend mainly on the degree of alteration development and the degree of fracture development.The quality of the volcanic lava reservoirs in the Hargawu Formation depends mainly on the quality of the volcanic lava reservoirs.Degree of crack development.Exploring the volcanic rock fluid identification method,the reservoir type is used for fluid identification,and the oil layer resistivity is significantly higher than the water layer.The research on capacity prediction was carried out.According to the types of reservoir space with different lithologies in different horizons,the capacity prediction factors were selected for capacity prediction.