Rock Acoustic Experiments And Study On Sand-shale Strata

Rock physics research mainly the fundamental nature and the general form of movements in the ground under high temperature and high pressure. As a bridge linked seismic data and reservoir characteristics and parameters, it has played an important role, such as 4D seismic reservoir monitoring, reservoir lithology prediction of seismic and the direct detection technologies of oil and gas that include "bright spots" and analysis of the change of the reflection coefficient with the change of angle of incidence, etc..With the increase of the intensity of the current oil and gas exploration, these facing research objects and geological problems that are demanding solution have become more complicated. For many exploration areas with complex geological features, we should base on the basic rock physics experiments, and then study change laws of elastic parameters and theoretical mechanism models, so these ways can be better to recognize laws of complex reservoir and can further guide effectively reservoir prediction and pore fluid identification.Rock physics research methods are mainly experimental methods, and the acoustic experimental research is the focus content of rock physics. In this text, based on a Key Project of Students Extra-curricular Science and Technology Research Program of Schlumberger (Grant No. SLBX0908) and a cooperative research project between China University of Geosciences (Beijing) and Peking University, which is called rock physics parameters experiment and research in WXS Depression, acoustic experimental study on WXS Depression reservoir has been done. The high temperature and pressure conditions in rock acoustic experiments are simulated, the basic properties data of core samples is obtained, including porosity, permeability, density, wave velocities of samples saturated with gas, water and oil and the report of rock thin identification. Therefore, the relationships between parameters and lithology, physical properties and fluid properties are built, meanwhile, the effect of sensitivity including reservoirs sensitivity and fluid sensitivity is analyzed, both fluid sensitivity parameters and reservoirs sensitivity parameters in the study area are elected.The following cognitions and conclusions are obtained through experimental study on the study area. (1) The general law of wave velocity of samples saturated with gas, water and oil is as follows: V_pw>V_po>V_pg; the values of their S wave velocity are nearly equal. The measured wave velocity is consistent with theoretical calculation wave velocity of Biot-Gassmann theory. (2) Through the experimental material data analysis, the empirical relationship models between wave velocity and physical parameters are gained, while the empirical relationship model between P wave velocity and S wave velocity is built, these results provide a basis for the further pre-stack seismic inversion of elastic parameters and the prediction of Vs by the use of V_p. (3) Through the pore fluid sensitivity analysis of different strata, optimization recommendations of the reservoir fluid sensitivity parameters are proposed. In stratums, the number of sensitivity elastic parameters on gas-water is 7, including F,σ_HSFIF,λρ,λ,σ, Kρand K ; while the number of sensitivity elastic parameters on oil-water is 4, including F,σ_HSFIF,λρandλ. Compared the experimental results of fluid sensitivity with the logging results of fluid sensitivity, we believe these are reliable.The main innovative results of this research are as follows. In the first undertaken experimental study of velocity on different oil density saturated samples, we can draw a conclusion that experimental results with samples saturated light oil are content with Biot-Gassmann theory and the experimental results with low-medium porosity samples saturated heavy oil are inconsistent with Biot-Gassmann theory.