The Study Of Methods For The Volcanic Reservoir Prediction And Fracture Detection

In recent years, with the worldwide discovery of the volcanic hydrocarbon reservoir, the volcanic reservoir is becoming new focus of reservoir prediction. In volcanic strata, the cracks can keep gas and improve the permeability of the reservoir, so fracture is an important factor for the volcanic reservoir; the volcanic rock is characterized with the variation of space distribution and the complex internal lithology, therefore, finding fracture in volcanic rocks is considered as research challenge inside subject.This paper is targeted to solve the problem of detecting fractures in volcanic reservoir. Firstly, we study the methods of volcanic reservoir prediction. Emphatically analyzed the elastic impedance inversion theory and its applications, and adding a post-stack attribute method in volcanic reservoir prediction. Then, we try to get the distribution of the fracture with the logging and seismic data. For fracture prediction with the logging data, we introduce the response of conventional logs and FMI logging; for fracture prediction with the seismic data, the pre-stack azimuthal anisotropy method is considered as the main idea to detect the fracture ,and the two other methods which we call"the difference between pre-stack near and far offset attribute"as well as"the stress field analysis"are also introduced. Through the discussion of the mentioned means, we draw a conclusion of the pre-stack seismic data centric ideas for the fracture detection in volcanic rocks combining with several logging and seismic methods. Firstly, as a high-resolution inversion method ,the pre-stack elastic impendence inversion is introduced to predict the volcanic reservoir while post-stack attribute method is used as a kind of supplement; then analyzing the change of kinetic property of seismic wave caused by fracture, predicting the density and direction of fracture with the azimuthal anisotropy, As a similar application, we also analyze the stress field for the structural fracture; finally, estimating the distribution of volcanic reservoir as well as fracture comprehensively. The key of this idea is"Detecting fracture with the thought of finding volcanic reservoir", the special advantage of the method is the high resolution and outstanding accuracy of prediction. As an example, this idea is used for reservoir prediction in test area. Based on the geologic state of the test area, we choose the right parameters and get the distribution of the volcanic reservoir as well as fracture. Comparing with the logging data, the result is satisfactory.