Pre-stack Inversion Of Deep And Reservoir Evaluation

Development seismic exploration technology in deep,ultra-deep and nonconventional oil and gas reservoirs has increasingly become the focus of attention with the difficulty of shallow,conventional oil and gas resources acquisition increases.Young's modulus,Poisson's ratio,Bulk modulus and shear modulus is the important elastic parameters of rock mass properties and fluid information statement.Through the quantitative estimation of the reservoir rock elastic parameters,rock and fluid properties,such as porosity,clay content,and water saturation,can be predicted.Those information is critical for oil and gas reservoir evaluation,follow-up exploration and development.AVO Pre-stack inversion is one of the most important analysis technique for oil and gas exploration,but also an important method of gets elastic parameters of underground media.Its core is the reflection coefficient equations of describe the laws of seismic wave reflection propagation.In contrast to the shallow reservoirs of deep reflection seismic data is often due to the lack of cross gathers data,extraction of three parameter inversion of AVO equation parameter matrix face greater instability,and the resulting error is delivered to the final inversion data,reduce accuracy and reliability of inversion elastic parameters.Based on above reasons,this paper starts with introducing a variable parameter formula to Aki-Richards approximation equation,derive the new Two-term reflection coefficient approximate equation by reasonably Fitting density reflection coefficient,constructing inversion technology and based on actual seismic data proceed AVO inversion of pre-stack,complete reservoir evaluation.In particular,this article completed the following work:(1)Research on basic AVO inversion theory,discussion the relationship of key elastic parameters of rock physical,and on this basis,by establishing the relation between velocity and density,derive the new Two-term reflection coefficient approximate equation in terms of Young's modulus and Poisson ratio,and the use of models and test data proved the reliability of the new method;(2)on the basis of(1)derive the new Two-term reflection coefficient approximateequation in terms of bulk modulus and shear modulus,and then structure a fluid identification factor based on the above two kinds of elastic parameters.Model and seismic data test shows the validity of new method for reservoir fluids testing.(3)The rock brittleness can be characterized by young's modulus and Poisson's ratio,fluid factor on synthesis of bulk modulus and shear modulus synthetic has a strong sensitivity for reservoir fluid.Utilization inversion methods of this article development for missing the far corner gathers pre-stack seismic data to AVO inversion,complete the reservoir evaluation of actual work area from both lithology and fluid.Interpretation results are consistent with well log data and actual development shows the theoretical and practical value of the thesis.