电缆取样泵抽资料在海上储层渗流评价的新应用

在电缆地层测试作业中,部分储层出现测压超压、流度可靠度低、受近井带泥浆滤液影响大等问题,制约了测压资料在储层渗流参数评价中的精细化应用。电缆取样泵抽具有测试时间长、排量大、泵抽体积多等特点,产生类似于钻杆测试的油气驱水（滤液）渗流机制,其压力扰动尺度大、地层渗流响应更可靠,能更准确表征储层渗流特征参数,且在泵抽过程中会同步记录下与渗流相关的诸多动态监测参数。目前对于泵抽动态监测参数的定量化分析应用较少,文中基于电缆取样过程中动态泵抽效率影响因素分析,提出了纯油气藏现场取样泵抽油气突破时间预测模型,用以指导现场作业;同时以达西渗流理论为基础,基于动态泵抽驱替效率分析,建立了储层有效渗透率评价新方法,进一步结合区域测试产能资料,建立区域单井产能快速评价模型。基于该方法评价有效渗透率及产能预测结果与实际测试结果平均误差分别为20%和10%,实际应用表明整体误差较小,该方法可靠、具有推广性。

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.