基于递减分析的页岩油气可采量评估

Review of shale oil and gas recoverable estimation based on decline analysis

目前,对非常规油气储层渗流特征缺乏全面深入的认识,对页岩油气井生产数据的分析和预测仍存在较大的不确定性,给页岩油气可采量评估带来很大的挑战。结合实例,通过分析页岩油气可采量评估主要环节的特点,得出如下结论:1)页岩油气井流动阶段诊断十分重要,可以有效降低后续递减分析预测可采量的风险。页岩油气井生产状态的改变,对可采量的影响不容忽视。2)根据在产井产量及可采量预测建立的典型生产曲线,其样本井的合理选取以及可采量的统计对比,直接影响未开发区块可采量的合理性。3)井间压窜干扰对老井和新井的可采量影响较大,需要对井距与压裂规模的匹配性做深入的研究。由于裂缝传导率和有效渗透率均随压力的下降而降低,同时存在井间干扰等因素,递减分析和数值模拟相结合是评价页岩油气可采量的有效方法。

At present,there is a lack of comprehensive and in-depth understanding of the seepage characteristics of unconventional oil and gas reservoirs,and there are still considerable uncertainties in the analysis and prediction of production data of shale oil and gas wells.By analyzing the characteristics of the main links in the assessment of shale oil and gas recoverable capacity,the following conclusions are drawn:1)The flow stage diagnosis of shale oil and gas wells is very important,which can effectively reduce the risk of subsequent decline analysis to predict recoverable volume.The change of production state of shale oil and gas wells has a significant impact on recoverable production.2)Based on the typical production curve established on the basis of the production and recoverable capacity prediction of producing wells,the reasonable selection of sample wells and the statistical comparison of recoverable capacity directly affect the rationality of recoverable capacity of undeveloped blocks.3)Inter-well pressure channeling interference has a great impact on the recoverable capacity of old and new wells,so it is necessary to conduct in-depth research on the matching between well spacing and fracturing scale.Because fracture conductivity and effective permeability decrease with the decrease of pressure and inter-well interference,the combination of decline analysis and numerical simulation is an effective method to evaluate the recoverable capacity of shale oil and gas.