The Flow Units Division and Reasonableness Verification of Chang 3 Lithologic Oil Reservoir of Huachi Oilfield in Ordos Basin

Key words: 
• lithologic oil reservoir

Abstract: To provide a reasonable means for the flow units division and verification in lithologic oil and gas reservoir. Considering the characteristics of Chang 3 lithologic oil reservoir of Huachi oilfield in Ordos Basin, the main parameters that controlling fluid flowing has been taken to divide flow units after formation division and facies differentiation, and mathematical method, microflow experiments, and dynamic analysis in macro has been adopt to verify the reasonableness of the flow units division in the research. The study results show: 1) three kinds of flow units are divided, they are called as A, B and C. The A flow unit is always located in the main face tract of underwater distributary river course, and its physical property is better. The C flow unit is always located in the edge of underwater distributary river course, and its physical property is not so good. The B flow unit is always in the middle of A flow unit and C flow unit no matter the face position or its physical property; 2) The methods of discrimination analysis, microflow experiments, and dynamic analysis in macro are effective to verify the reasonableness of the flow units division. The correct rate of 100 data points that be selected randomly have been over 95%; the same flow units have similar microflow characteristics, and different flow units are obvious disparate, which reflect in the order of fluid entry, the fluid displacement mode, and the remaining oil types; the product dynamic characters are related with the classification of flow units, reflecting in initial production, the hygroscopic state of water wells, and response and breakthrough of oil wells; 3) C flow units and the joint areas of different flow units between injection well and production well will be the main oilrich of residual oil. And an injection well had better be opened the same flow units at the same time for reducing the water level of interference, and as while the same flow units should be opened to reducing the injected water finger advance, and so the oil recovery will be enhanced.