密闭取心饱和度校正数学模型研究.docVIP

密闭取心饱和度校正数学模型研究 辛治国1 侯加根1 冯伟光2 （1.中国石油大学（北京）地球科学学院，北京102249；2.中国石化股份胜利油田分公司 地质科学研究院，山东 东营257015） 摘要：利用密闭取心井资料分析油、水饱和度是目前最直接有效的方法，但是由于岩心上提导致的孔隙体积变大、降压脱气和钻井液侵入等过程的影响，岩心测试油、水饱和度之和一般均只有75%-85%，油、水饱和度都有较大损失，因而需要对油、水饱和度进行校正，争取求准饱和度数据。本次研究进行了挥发过程及岩心上提过程的室内实验，发现密闭取心降压脱气过程是造成油水饱和度损失的主要因素，目前实验条件难以如实模拟这一过程，研究中以流体分流率原理为核心，建立了降压脱气的数学校正模型；降压还会导致孔隙增大，岩心的覆压孔渗实验能够准确反映这一变化，为油水饱和度校正提供依据。建立的密闭取心饱和度校正数学模型精度与保压密闭取心的测试结果相当，具有现场推广意义。而对于钻井液浸入造成的油水饱和度损失而言，数量比较小，但是实践证实疏松砂岩中强浸的岩心样品油水饱和度数据需要校正，校正量一般不大于2%。 关键词：密闭取心井 饱和度损失 校正模型 降压脱气校正 钻井液侵入校正 Correction Model of Oil and Water Saturation in Sealing Core XIN Zhiguo1 HOU Jiagen1 FENG Weiguang2 (1. China University of Petroleum, Beijing, 102249; 2. Geological Scientific Research Institute, Shengli Oil Field Ltd.Co.,Ltd., Shandong Province, 257015, China) Abstract: It’s the most straight and available method for analyzing oil and water saturation to drill sealing core well. But because of the processes of raising cores and mud invading, the total of oil and water saturation is only 75%-85%. There are many losses in oil and water saturation. Oil and water saturation should be corrected for getting exact oil and water saturation data. In this research, volatilization process and raising cores process are tested for correcting. The process of degassing in the raising cores process is the main reason causing oil and water saturation loss. Now, its very difficult to simulate this process really. The correction model of degassing causing by pressure dropping is built based on sub-flow rate theory. Because of Pressure dropping , porosity of the core becomes bigger and bigger. But overburden pressure experiment can test this change accurately, and provides the basis for oil and water saturation correcting. The precision of this correction model is similar with the test of pressure maintaining sealed coring. And the influence caused by mud invading should be considered in coring of unconsolidated sand reservoir. Oil and water saturation should be c