New Application of Pumping Data of Wireline Sampling in Offshore Reservoir Seepage Evaluation

In wireline formation testing, the problems such as overpressure, low mobility reliability, and mud filtrate near wellbore in some reservoir will restrict the fine application of pressure data in the evaluation of reservoir seepage parameters. The wireline sampling has the characteristics of long testing time, large displacement and more pumping volume, and the oil/gas-drive-water/filtrate percolation mechanism similar to drill pipe testing is produced by pumping with large disturbance scale, more reliable formation seepage response and more accurate reservoir seepage flow characteristic parameters. Besides, many dynamic monitoring parameters related to seepage flow will be recorded synchronously. At present, few of the dynamic data has been researched and utilized. Based on the analysis of the factors affecting the pumping efficiency of dynamic pumps during wireline sampling, a prediction model of breakthrough time for pumping in pure oil and gas reservoirs is proposed in the paper, which can be used to guide field operations. Meanwhlie, based on the Darcy Percolation Theory, a new method of reservoir effective permeability evaluation according to dynamic pump displacement analysis is established. Furthermore, the rapid evaluation model of regional single well productivity is established in view of the regional test productivity data. The error between the prediction results of effective permeability and productivity evaluation by the above method with the actual test results is small. The practical application of the method is reliable, and the method is extensible.