High-precision Stochastic Inversion Method And Its Application In SLG Gas Field

The analysis of oil-gas reserve in the Chinese continental in the recent year shows, lithologic reservoir occupying from 20% in the early 1990 s to 55% in the current out of the total discovery, indicating that lithologic reservoir is very important for oil-gas development. Delicate oil-gas exploration is one of the key in increasing the current oil-gas reserves. With regard to delicate oil-gas exploration, the results of high-precision seismic inversion play a more and more important role in oil-gas reservoir description and reservoir prediction. Because the inversion result can actually reflect underground geological structured and reservoir lithologic characteristics, and can greatly raise the percentage of drilling hits.SLG gas field is one of large gas field in our country, belong to subtle lithologic gas pools of tight sandstones. Its reservoir with gas single thin effective thickness, poor lateral continuity of sand body, space change is big, the single plane distribution is not stable, and strong heterogeneity and complex characteristics of sedimentary sand body type.In order to describe the interbedded sand-shale reservoirs precisely in SLG gas field. In this paper, we conducted a systematic analysis and research form the conventional deterministic inversion to the finer high-precision stochastic inversion. By detailed study of the key technology and parameters in the process of inversion, And on this basis to study the objective interval in H8 segment as the goal, in the high precision of inversion results to the sand body distribution is analyzed. The main research and key results of this paper are as follows:(1) In conventional post-stack inversion based on the advantages and disadvantages of the analysis and research, through the optimization of conventional random methods and improve the proposed a stochastic inversion method has high precision, and the formation of the SLG gas field classification, sedimentary characteristics, reservoir characteristics has carried on the comprehensive analysis and summary, combining with the characteristics of its established a set of suitable for SLG gas field inversion process.(2) Through analyze the parameters of pro-stack inversion in detail and ensure the inversion property using a variety of accurate analysis.(3) By comparing with the result of conventional stochastic inversion method and high-precision stochastic inversion, its show that high-precision stochastic inversion in SLG gas field has a better effect.(4) Based on high precision of inversion results, combined with the geological understanding, sand body in SLG area distribution characteristics are analyzed, and by using single sand body error analysis was carried out on the high precision inversion result of the random reliability further validation. In conclusion, using the high accuracy stochastic inversion in SLG gas field has obtained the good application effect, it can improve the reservoir prediction accuracy and has the important practical application value.