Research On Petrophysical Modeling Of Carboniferous Volcanic Rocks In The Junggar Basin

Nowadays,the exploration of Carboniferous volcanic rocks in the Junggar Basin has been gradually intensified and some breakthroughs have been made,showing that the Carboniferous in the Junggar Basin has a great exploration prospect.However,geophysical well logging data and conventional petrophysical experiments show that the volcanic rocks in this area have strong heterogeneity and large changes in lithology,which makes the identification of volcanic rocks a difficult task.In order to improve the recognition accuracy of volcanic rocks and provide favorable technical support for the future exploration of oil and gas,this paper analyzes rock petrophysical properties of different volcanic rocks on the basis of rock sample test data of Shengli Oilfield Exploration and Development Research Institute and well logging curves in Junggar Basin.Parameter model,and correct the parameter model by forward modeling.1.The density difference between the Carboniferous and the overlying strata is the largest,and is a strong magnetic layer and a high resistivity layer,which is closely related to the existence of the igneous rocks.From the basic volcanic rocks to the acid volcanic rocks,the density and resistivity gradually decrease,and the 5 kinds of volcanic rocks have very weak magnetic properties,and the others show different magnetic properties.2.Based on sensitive parameters and rendezvous analysis,a petrophysical model for volcanic rocks in Junggar basin is established.Mainly including: The later the geologic age is,the smaller the ratio of the density of the different volcanic rocks to the P-wave velocity;The intersection of compressional wave velocity and density of different volcanic rocks can roughly distinguish basic,neutral and acidic rocks;The intersection of density and magnetic susceptibility can better distinguish the specific lithology;The linear relation between the longitudinal wave velocity and the resistivity,the longitudinal wave velocity and the density of the volcanic rocks is different,and the different types of volcanic rocks can be distinguished by the slope and the rendezvous relation.3.Through the forward analysis of gravity and magnetic characteristics,the gravity and magnetic anomaly characteristics under different conditions are obtained,which is of guiding significance for the identification of volcanic rocks.The results obtained from the inversion of petrophysical relationship can accurately identify volcanic rocks with different lithologies.