致密砂岩气藏剩余储量定量表征与差异化挖潜对策OA

The successful development of the Sulige Gasfield has made a tremendous contribution to the continuously increasing tight gas production in the Ordos Basin.Currently,the central area of the gasfield has entered the middle-late stage of development,with both recovery factor and producing reserves reaching high levels.It is necessary to quantitatively characterize the spatial distribution of remaining reserves in tight sandstone reservoirs at this stage,and customize differentiated potential tapping strategies.In this paper,taking Block Su 36-11 in the central Sulige Gasfield as an example,the distribution of tight sandstone reservoirs was finely described.On this basis,a research method integrating three-dimensional geological modeling with CMOST intelligent history matching numerical simulation was adopted to calculate the development scale and distribution frequency of effective sand bodies,and describe the remaining tight gas reserves in a stepwise manner.The following results are obtained.(i)During the sedimentary period of Block Su 36-11,the hydrodynamic forces were strong.Sand bodies were extensively and continuously developed under the control of superimposed zones of braided rivers.(ii)The development frequencies of effective sand bodies in the eighth member of the Permian Lower Shihezi Formation(He 8 Member)and the first member of the Permian Shanxi Formation(Shan 1 Member)are relatively high,with the frequencies of 14%,56%,and 30%for the upper and lower submembers of He 8 Member,and Shan 1 Member,respectively.(iii)The adopted CMOST module of CMG software enables automatic history matching and parameter optimization for gas wells.The quantitative evaluation results from numerical simulation indicate that the remaining gas is concentrated in the lower submember of He 8 Member and the second sublayer of Shan 1 Member,and it primarily occurs as interlayer remained gas and inter-well remained gas,and incomplete fracturing remained gas locally.(iv)For twenty-one well areas under four categories divided by reserve producing degree in the block,production strategies are researched separately depending on types of well areas.It is concluded that differentiated potential tapping strategies,such as local well pattern infilling,reperforation,old well sidetracking,and overall deployment,should be implemented according to the specific types of well areas to enhance the gas recovery of the block and thus contribute to the sustaining stable production in the Sulige Gasfield.