CHEN Minfeng, WANG Zhaoqi, SUN Hedong, WANG Yan, CHEN Lu, ZHANG Qichen
1 College of Petroleum Engineering, China University of Petroleum-Beijing, Beijing 102249, China 2 Research Institute of Petroleum Exploration and Development (RIPED)-Langfang Branch, Langfang 065000, China 3 Research Institute of Exploration and Development, Xinjiang Oilfield Company, Karamay 834000, China
The typical Blasingame decline curve has enhanced production data analysis, which can not only account for variations in bottom-hole pressure, but also handle changing fluid properties upon reservoir depletion more confidently. However, reservoir stress sensitivity is not considered by the Blasingame method. This paper introduces the seepage characteristics of stress sensitive reservoirs and builds up the mathematical model which is then solved by numerical methods at a constant-rate condition. In the solution, the non-isometric difference is used and the constant-rate condition is transformed into the inner boundary condition of the first space unit, the effect of stress sensitivity on permeability is also handled through explicit methods. On this basis, production decline considering stress sensitivity was obtained according to Blasingame non-dimensional definitions. The calculation results show production decline curves of stress sensitive reservoirs are parallel with each other in each group during the period of boundary control flow. Besides, the corresponding curve moves down with the increase of dimensionless distance. As the stress sensitive coefficient increases, improved Blasingame production decline curves all move down. Case analysis shows that the interpretation results of the improved Blasingame method are more consistent with the low permeability and stress sensitive reservoir.
