Study On Macro Occurrence Pattern And Potential Tapping Measures Of Remaining Oil In The Middle-late Stage Of Reservoir Development

At present, most of oil fields in our country have been in the middle-late development stage, with the overall production showing features of large water injection and high water cut, increasingly complex remaining oil distribution, and gradually difficult development. With further cognition of remaining oil distribution, it will provide the theoretical basis of EOR for many oil fields to summarize occurrence patterns of remaining oil systematically and to put forward potential tapping measures. Means of literature research, theoretical investigation, numerical reservoir simulation and field application have been applied in the study. Based on analyzing geology and development factors of macro remaining oil in the middle-late development stage, distinct conceptual models are constituted, and 6 kinds of occurrence pattern of remaining oil are summarized through analyzing simulation results, which are stated as follows: aggregate block and continuous distribution, sporadic block and dispersed distribution, local stratiform and banding distribution, holistic stratiform and banding distribution, edging distribution and microtrap distribution. Potential tapping measures for each kind of occurrence pattern of remaining oil have been put forward by analyzing the technical advantage and adaptability of four kinds of technologies: horizontal well, profile control and water plugging, well pattern infill and adjustment, liquid production increasing and matching hydrodynamics method. Aggregate block and continuous distribution is mainly tapped by profile control and water plugging and horizontal well technology; sporadic block and dispersed distribution is mainly tapped by profile control and water plugging, well pattern infill and adjustment and cyclic water-flooding; local stratiform and banding distribution is mainly tapped by profile control and water plugging, well pattern infill and adjustment and liquid production increasing and matching hydrodynamics method; holistic stratiform and banding distribution is mainly tapped by well pattern infill technology; edging distribution is mainly tapped by horizontal well and well pattern infill technology; microtrap distribution is mainly tapped by well pattern infill and adjustment technology. According to the oil field application, these occurrence patterns and potential tapping measures are reliable which will provide significant guideline for recovery enhanced.