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缝洞型油藏油气分布受多次成藏、不同后生作用破坏改造和储集空间非均质性等因素影响,常会造成油气运移聚集差异较大、油藏物性平面分布极其不均匀等状况。常规解析解试井分析理论受模型简化的限制,一般不能满足该类油藏渗流问题的求解需要。提出了井钻遇溶洞的试井解释模型,建立了相应的数学模型,并采用Laplace变换和Stehfest数值反演算法进行了求解。分析了溶洞储能比、溶洞大小对压力响应的影响,分析了其规律:溶洞半径越大,早期曲线斜率越大。溶洞相当于扩大了井径,增加了“井筒储集系数”;溶洞储能比越小,溶洞反映越明显;不同储能比早期曲线平行,而且溶洞储能比越小,截距越大。还提出了井钻遇溶洞油藏的试井解释方法,并编制了实用软件,利用模型对塔河油田某井进行了解释,解释结果与地质模型和钻井数据一致。
The distribution of oil and gas in fractured-hole reservoirs is affected by many factors, such as multiple reservoir formation, alteration and alteration due to different epigenetic effects, and heterogeneity of reservoir space, often resulting in large variations in hydrocarbon migration and accumulation and extremely uneven distribution of reservoir physical properties . Conventional analytical solution Well test analysis theory by the simplified model restrictions, generally can not meet the seepage problems of this type of reservoir needs to solve. A well testing interpretation model for well drilling in karst cave was proposed. The corresponding mathematical model was established and solved by Laplace transform and Stehfest numerical inversion algorithm. The effect of karst energy ratio and karst cave size on pressure response was analyzed. The regularity was analyzed: the larger the karst cave radius, the larger the slope of early curve. The karst cave is equivalent to expanding the borehole diameter and increasing the wellbore storage coefficient. The smaller the karst energy storage ratio is, the more obvious the karst cave reflection. The different energy storage is parallel to the earlier curve and the karst energy storage ratio is smaller. The intercept Big. A well test interpretation method for wells drilled in karst reservoirs was also proposed. Practical software was compiled and a model was used to explain a well in Tahe Oilfield. The interpretation results are consistent with the geological model and drilling data.