古油气水界面恢复方法综述

SUMMARIZATION OF THE PALEOHYDROCARBON-WATER CONTACT RESTORING METHODS

油气藏油气水界面的变迁记录了油气藏形成以后调整、改造 ,甚至破坏的历史。恢复各地质历史时期的古油气水界面的位置 ,可以确定地下烃类流体运聚成藏的时间 ,恢复流体成藏后的变迁、调整过程 ,帮助我们认识油气藏形成与分布的规律。给出了古油气水界面恢复的 6种方法 ,并指出了各种方法适用的地质条件、存在问题及发展方向。 6种方法中 ,相对而言 。

Changes of the hydrocarbon-water contact are records of th e history of adjustment, reconstruction and even destruction of the reservoir. By restoring the positions of paleohydrocarbon-water contact of petroleum reservoir in different periods in geological history, we can determine the timing of migration,accumulation and adjustment of reservoir, which will help us understand the law of formation and distribution of petroleum. This paper generalizes six methods concerning the restoration of paleohydrocarbon-water contact (by researching the affection of filling and pouring accumulation of oil and gas on the diagenesis of rocks, the variations of tar, the positions of tar mats, the changes of GOI, the isotopic composition of carbonate cement and basin numerical simulation), and shows the suitable geological conditions, problems and development of every method. Among the six methods, due to imperfect isolation between the system of diagenesis and external environment, when we restore the positions of paleohydrocarbon-water contact by researching the affection of filling and pouring accumulation of oil and gas on the diagenesis of rocks and variations of the isotopic composition of carbonate cement, the fresh water of outside can enter system and change the diagenesis conditions of it, which will affect the results of prediction. In addition, though using the positions of tar mats in reservoirs is a more valid method to find paleohydrocarbon-water contacts, not all reservoirs have tar mats and not all tar mats denote the positions of paleohydrocarbon-water contacts. So it is a relatively better way for us to restore paleohydrocarbon-water contact by researching the variation of GOI. These methods involved above all need select samples and do experiments. During this process, many factors, such as the levels of selecting samples, the amount of samples, the qualities of samples, the degree of exactness of measuring instrument, the qualities of measuring crew and so on, will affect the result of experiments, and selecting different algorithms and using different data also will lead to different results in basin numerical simulation. Hence, if we want to obtain the satisfactory results, we need to combine all the methods in the course of practice.