Reef-flat Reservoir Prediction On Zhujiang Formation Of Dongsha Uplifting Located In Zhujiangkou Basin

The proven hydrocarbon reserves of reef-flat reservoir account for a high proportion among various carbonate reservoirs. Reef-flat arouses a great attention because of its high productivity, high recovery and low cost of exploration and developing. Nevertheless, the hydrocarbon reservoir of reef-flat is very difficult and demanding to explore, which led to a low success in both reserve prediction and prospection, because the reef reservoir has a high heterogeneousness, invisible geophysical feature anomaly and ill-defined geometric. As my research’s target area, DongSha uplifting, located in ZhuJiangKou Basin, widely developed carbonate sediment, where a lot of reservoirs were discovered with a good potential for exploration. But a lack of efficient technologies in carbonate reservoir prediction of lithological trap constitutes a restriction on carbonate reservoir exploration.This article was written based on a comparative research of well-log data and litho-physical testing to build up some correlations of reservoir parameters, geophysics feature parameters, lithologically dynamic-static elastic parameters, and lithological change. The thesis also study reservoir reflection features by means of numeral simulation techniques. By the application of pre-stack and post-stack parameters inversions, some specific-purposed trials are implemented and a synthetic analysis is conducted to summarize some technical laws of reservoir prediction and fluid identification. The accomplishment achieved from the research can be shown as follows:(1) The study of geophysical features and reservoir prediction parameters of reef-flat reservoir is performed by means of well-log and litho-physical testing. The litho-physical testing gives out fundamental physical parameters for reservoir’s conditions and its seismic wave field features. And the well-log coefficients present the well-log parameter characteristics of distinct reservoirs and various facies-suites. Moreover, optimization is carried out to choose the porosity to be the finest parameter for reserve prediction and build up a correlation model among elasticity, geophysical parameter and porosity. And it is proposed that Vp/Vs and frequency absorbing factor can work as 2 liquid-identifying sensitivity factors.(2) By application of research thought combining forward and inversion as a guideline, the thesis develops and completes a numerical simulation method for reef-flat reservoir, and check the method efficiency by using the inversion results. The paper works out a new numerical simulation method applicable for both microcosmic elastic equation and macrocosmic scalar wave equation of heterogeneous media, make perfect a seismic numerical simulation approach applicable for fluid-based porous media, and a pre-stack seismic numerical simulation method based on one-way acoustic wave equation. It takes advantage of inversion technique to verify the efficiency of the numerical simulation approach.(3) The paper promotes a reef-flat reservoir prediction method with a core of pre-stack reservoir porosity inversion and its special distribution laws, based on high resolution seismic data. The method has been popularized in practical production and proven by drilling data. Depending on the model created between the foresaid seismic feature parameters and porosity, the thesis makes use of the inversion of pre-stack elastic impedance and the seismic feature analysis technique and forms a set of multiparameter-combined porosity inversion method and a hydrocarbon detection means, relying on pre-stack elastic parameters and post-stack seismic absorption characteristic analysis. By this method,3 favorable goal areas were found successfully through prediction of the major research area. One of favorable goal area LH11-1E-1 has been proved with the success of the 1st well, LH11-1E-1, that its demonstrated reserve is predicted to be about 50-60MM m3.