| HD111 borefild is located at the northwest of Hadexun oil field,the Donghe sandstone reservoir is the main reservoir of HD111 borefild,which has the characteristics of deeply buried and thin, there are many interlayers developed in the reservoir, and the interlayers is widly distributed,bring the greater impact on the distribution of the fluid.Now,the oil-water distribution is not clearly in the HD111 borefild, restrict the use of reserves of this block, by the august 2015, the cumulative oil production was 55.74×104t, the production level is only 9.81%, the production and development potential is huge,figure out the characteristics of oil-water distribution and find out the suitable development mechanism of the borefild is the urgent problem to be solved.According to the Donghe sandstone outcrop section,core observation,conventional logging and imaging logging,the interlayers can be divided into three types in the reservoir of the HD111 borefild:the muddy interlayer,the calcareous interlayer and the calcium clay interlayer.Based on the logging response characteristics of various interlayers,the identification standards of the three types sandwich layers in the study area are established,summarize the characteristics of the three different interlayers:low acoustic wave,high density,high electrical resistivity,low conductivity, low porosity and low permeability, the main difference lies in that the muddy interlayer has the larger gamma value,while the value corresponds to the calcareous interlayer is low,and value of the calcium clay interlayer is between the two.To study the oil-water distribution of the HD111 borefild,in this paper,mainly according to the core observation,logging interpretation results and the conventional logging,and so on,identify the oil-water interface of single well in the study area,base on the identification of the single well oil-water interface,researching and analysing the oil-water distribution characteristics in the study area by selecting multiple wells,and the distribution characteristics of oil-water in HD111 borefild is summarized,it is the first time to propose the oil-water interface is ladder like existence from west to east direction in the study area,which is different from theinclined oil-water interface that the domestic and foreign research scholars supported.The existence of ladder shaped oil-water interface,have the great correlaiton with the interlayer's displacement pressure,and its closed oil column height,based on the conversion factor of the capillary pressure, convert the experimental results of the displacement pressure by mercury test in the laboratory to the actual displacement pressure under the condition of formation,then the probably closed maximum height of oil column under the condition of stratum can be got.Based on the geological understanding of the oil-water interface and distribution of stratum(sand 11, sandwich 9),using stochastic modeling method.In the case of correction of porosity,permeability,oil saturation,the distribution of porosity,permeability and saturation can be obtained under the formation conditions,the model of the real distribution of porosity,permeability and saturation eventually built up.By reserves calculation,the geological reserves of HD111 borefild is 589.86×104t,compare with the geological reserves of 568.48×104t by volume method of calculating, the error is only 3.62%,the established model is reliable in the range of error tolerance.In order to research the mechanism of Donghe sandstone reservoir of HD111 borefild,under the premise of the historical fitting of the production of each well in the study area,by simulating the production effect of different injection production well,horizontal section length of horizontal well,injection production well spacing,the direction of the horizontal well spacing and production well proration.Hold that:the best developing plan is vertical wells injection and horizontal wells production pattern;the most reasonable horizontal section length is 400m;the most suitable injection production well spacing is 600m;the best direction of the well distribution is along the direction of the lower part of the structure,that is the direction of east and west;the suitable proration is 25m3/d,which can guarantee the stable production for 20 years and obtain the maximum yield of the oil field.On the basis of the research of the develop mechanism,combine with the actual geological characteristics of the study area,four sets of mining plan are designed from the angle of the direction of the horizontal well distribution,by compare the simulation results, the scheme two with the least wells and the maximum cumulative oil production, the development effect is the best,expected to 2035,the level of the production will reach to 25.91%. |
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