The Application Of Log Facies General Analysis In Iithologic Gas Sedimentary Facies And Reservoir Prediction

At present, the research trend of geophysics in petroleum exploration anddevelopment has changed a lot, which focus on quantitative research, microcosmicand partial specific research. All these changes need new method and new theory,which can be instead of traditional and exiting method. Logging facies generalanalysis, which is the necessary effective technology in petroleum exploration anddevelopment, can take full advantage of plenty geology information in logging data,and identify its video feature. Especially concerning multi-scale analysis, it also candetect periodic element in the logging signal with changeable differentiate ratio,which avoids man-made affection.Based on the walve-let transform multi-scale analysis and the multi-scale fractalanalysis, this dissertation conducts a series of researches on geophysical property ofreservoir lithology on different frequency scale. First of all, this dissertation describesthe theory formulation of self-affine fractal structure in detail. Through spectralanalysis technology, we found that the energy spectral density of logging facies is afunction of wave number. Meanwhile, we obtained the D value and analysed itsstatistical distribution regulation and its geological meaning. Based on the aboveresearch, this dissertation describes the principle of walve-let transform multi-scaleanalysis and uses it in logging facies fractal research. The result proves thatmulti-scale analysis can improve the resolution power of logging curves. In the end,we apply both the two analysis methods in one lithology gas-reservoir, mark offdepositional system and sedimentary micro-facies and obtain reservoir distributionregulation.Through the frequency analysis on5logging facies (including natural gamma,self-potential, acoustic travel time, density and neutron) of21wells in one lithologygas-reservoir, the analysis result of all the five fractal dimension show that the fractaldimension value changes a little, which illustrates that the geology structure isconsistent with the forming process in this research area. So we can consider this areaa scale-invarian area on the view of macroscopic. The multi-scale analysis graph on the typical well Jin6indicates that the logging information at any depth can bedecomposed to slow rate low frequency part and high frequency part. The range ofvariation concerning large, medium and small scale is different. Comparing with theother logging facies, the natural gamma (GR) can be more sensitive to reflect thevariation of shale content. So it is effective to apply the natural gamma (GR) toresearch high frequency strata cycle. From the multi-scale analysis on5logging faciesof well Jin6, we find out that reservoir physical property is so sensitive to thesmall-scale component of lithologic and physical parameter (high frequencycomponent) and whether the reservoir has oil and gas or not has large affection on thesmall-scale component.