Reservoir Geological Modeling Of Chang 2 In Nangou Region Of Xiasiwan Oilfield

Chang 2 reservoir is the main oil-bearing formation in Nangou region of Xiasiwan oilfield of ordos basin. It occurs some problems such as poor variation of oil water interface, the high ratio of comprehensive water-cut, the low productivity of a single well, the difficult determination of water injection limit, the large difficulty of controlling water, the serious one-way spearhead of water injection and the strong heterogeneity.3D geological model of Chang2 reservoir is developed from the perspective of fundamental geological basic problems..Meanwhile, it also constructed a there-dimension-space dataset of reservoir parameter, which can not only establish a foundation and provides some basis for further study, but also be instructive for later development deploy and further adjusting tappingpotential.Some outcomes have been achieved based on this study.1. Study area is located in gas accumulation zone in the Mesozoic, Ordos Basin. In the oil exploration stage, the phenomenon of blowout occurred in many wells. Through analysis, the big contrast of reservoir burial depth in Ancient and modern, close to oil source, large range nose-shaped uplift and development of crack are the main reasons of gas accumulation.2. According to the principle of stratigraphic correlation, Chang 2 reservoir of Nangou region of Xiasiwan oilfield would be separated into three oil sub-layer which including Chang 21, Chang 22 and Chang 23.The key oil-bearing formation Chang 22 was further divided for Chang 221, Chang 222, Chang 223 by Sedimentary cycle. In the basis of the accurate division of layer, surface structure of each layer was constructed, and the reason of nose-shaped uplift structure is analyzed.3. Combined with the regional geological setting, using the analysis of lithofacies and well logging facies, three kinds of micro sedimentary facies are distinguished, including the sandstone of under water distributaries channe, subsea natural barrier and interdistributary bay. And sedimentary facies spatial distribution characteristics of each oil sub-layer is discussed. The sandstone of under water distributaries channel is the main reservoir in study area.4. The paper described the character of petrology, physical property, distribution of sandstones and pore structure of Chang 2 reservoir in study area, and emphatically analyzed the character of reservoir inter-layer, intra-layer, plane and microcosmic reservoir heterogeneity. Combined with macroscopic and microscopic features synthetically, the ultra-low permeability reservoir characteristic and heterogeneity are studied.5. Based on the theoretical analysis of Deterministic modeling and Stochastic modeling, comparing the applicability of many different models and algorithms, using PETREL software, the three-dimensional geological model is established, which includes the structure model, sedimentary facies model and attribute model. Then, it has a more intuitive understanding of reservoir distribution in three dimensional spaces.