| Oil field exploitation in our country is confronting the critical facts that from easy development areas to hard areas, from the oil pool which high hydrous and high degree of exploitation, from the balance of reserve and exploitation to serious imbalance. Considering the complexity of continental reservoir, all that above-described bring forward a lot of new difficult problems to oil industry, so there is a long way to go.Sedimentary microfacies is the most basic and important genesis unit which shows the reservoir physical properties and oil pool distribution. Reservoir simulation aims at establishing an oil pool geological model which can be used to study the distribution of residual oil saturation. This paper mainly concerns how to utilize the known drill site data to estimate the variaty of reservoir sedimentary microfacies and a variety of rock physical parameter in the districts with no dill site data between wells.Underground reservoir is determinate on itself. That is it has determinate properties and characteristics at every position. But it is complex, too. Many complex geology process affect it, so it has the complex spatial arrangement of reservoir structure and spatial variation of reservoir parameter. In the course of reservoir description, we have so much difficulty in mastering its determinate and substantial characteristics or properties at any scale because of lack of record. Especially to the land reservoir with uncontinuity and heterospheric, it is more difficult in characterizationing. Because of the deficient recognition, reservoir description typifies indeterminacy. These reservoir properties that need "guess" are random distribution. With the appearance of stochastic simulation, it is possible for us to forecast the distribution of reservoir Sedimentary microfacies accurately.The theory of geologic variable spatial variability is the basis of stochastic simulation. Using variogram to describe the spatial distribution of geologic variable. Variogram shows that the variant degree of geologic variable varies with the distance, and emphasizes on the data configuration in space so that we candescribe the relativity of reservoir parameters in space by geological regulation quantitatively. Five main steps are included during using the theory of variogram to analysis geologic spatial variable: 1?Analyze drill sit data with statistical method. 2?Get experimental variogram 3?Fit experimental variogram.4?Match the experimental variogram. 5, Detect and modify variogram.Stochastic simulation is a method that is on the basis of known information, using stochastic simulation to produce alternative, equal probability reservoir model. The method manifests that reservoir parameter out of control point is indeterminate, that is so called stochastic. Therefore, the reservoir model established with stochastic simulation is not only one, but several. That is there are several possibilities at a given range, so that satisfy the truth requirements of exploitative decision at a range.Comparing with the traditional geostatistics (such as Kriging), stochastic simulation typify the fowling :(1) The simulation algorithm is on the basis of model, different model may use different simulation algorithm.(2) The result take the emphasis on global relativity. It offers the metric of indeterminateness to attributive spatial distribution of reservoir in general. But Kriging can not assure conditionalization to statistic, and the bar chart and covariance in the result may have much deviation comparing with genesis data.(3) Kriging has only one numerical solution, but stochastic simulation has multi-valued solution. Just these identity and difference implicate the indeterminateness hided in the probabilistic model.Hence, stochastic simulation can characterize the heterospheric of reservoir sedimentary microfacies and simulate and forecast its distribution.Pu-taohua oil field, situated in the border land of An-da city and Zhao-yuan country, is one of the oil fields in the south of Da-qing C...
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