Study On The Production Capacity Of Horizontal Well Segment Completion In Bottom Water Reservoir With Different Completion

Bottom water cresting has been the bottleneck which restricts the economic benefit of horizontal well which is being used to develop bottom water reservoir. Now there are various methods of controlling bottom water, but it is inevitable that bottom water will break in somewhere of horizontal well in advance. After the breakthrough of bottom water, partially completed horizontal well could block off the section that has been broken in by bottom water, which could keep other sections normally working, extend the life of horizontal well and improve the recovery. Moreover, it could also curtail the costs of well completion and so on. Undoubtedly, partially completed horizontal well will be widely applied.Compared with only utilizing ECP, partial completion with blank section and ECP, the research object of this thesis, could delay the lateral migration of bottom water and truly extend the life of horizontal well in bottom reservoir. According to methods of mirror and the superposition of pressure drop, the pressure loss model of reservoir was established by using source function. Based on the seepage characteristics of different completion in near-wellbore area, the near-wellbore flow model was gained. The pressure loss model of wellbore was founded in accordance with the conventional pipe flow in blank section and the variable mass flow in production section. Then by coupling these three models, the productivity forecast model was derived. And its calculation method was given, and the relevant program was made. This coupling model could calculate the productivity of perforated casing, screen and gravel-packing completion in partial open-hole, perforating and compound horizontal well under the influences of the horizontal well trajectory, the horizontal wellbore pressure drop and the skin distribution.By using the real data of horizontal well in an oil field, the productivity of different completions in homogeneous and inhomogeneous bottom water reservoir were analyzed and compared. And the curves of production decline, distribution and the relevant variation with the time of flow rate and wellbore pressure were got, while the pressure drop of wellbore and the contrast curves of the variation in production and flow rate in different completions also were gained. Furthermore, some knowledge and inspiration were gained by analyzing the features and discrepancies of these curves. And the superiority of combined partially completed horizontal well was verified. In addition, the influences of the parameters of partial completion which including open degree, open numbers and the position of blank section on the stable time of production, stable production and the homogeneity of flow rate under the practical open-hole, perforating, compound and ideal open-hole perforated casing completion were analyzed and compared. According to the research results, the scheme of parameters of partial completion with or without bottom water was made.The outcomes of this research could be the theoretical basis of optimizing the completion method and parameters of partially completed horizontal well. And it could help to instruct the oil companies to design the partially completed horizontal well.