试论泥岩压实作用与油气初次运移

A STUDY OF CLAY COMPACTION AND PRIMARY MIGRATION OF OIL AND GAS

陈荷立 汤锡元

Chen Holi Tang Hsiyuan

长期以来一直将泥岩压实作用作为石油初次运移的主要动力,认为母岩中生成的烃类,是以溶解状态随水一起离开母岩进入储层的.近年来由于有机地球化学及其分析技术的飞跃发展,以干酪根热降解为核心的晚期生油理论得到了普遍赞同.而与此同时,在石油生成与初次运移理论间却出现了严重的矛盾.因为,按照以往对压实作用的理解,泥岩在埋藏及压实过程中的排水量只在浅处较大,髓着深度加大则迅速降低;又因烃类在水中的溶解度一般仅万分之几,显然晚期成岩阶段的排水量是难以满足石油初次运移需要的.

The study,the clay compaction concerned,based on the data of time-depth ralationship of acoustic wave transmission from nearly 50 walls inBiying depression proves that:1)There is usually a great difference ofclay compaction in different parts,of the same depression,and the oil andgas accumulation are closely associated only with the areas where both hy-drocarbon generation and primary migration occurred;2)The anomalouscompation section of the clay after the organic matter maturation may deter-mine the possible depth of primary migration in this area;3)The rapidlycompacted zones of the anomalous compaction secion seem to be the most fa-vourable intervals for the primary migration of the hydrocarbon;4)Thedepth,favourable to primary migration,has determined the main stage of theoil and gas accumulation;5)The highly compacted clay section may forma caprock which sealed by pressure and affect the depth of longitudinal dis-tribution of oil and gas accumulation.

10.11743/ogg19810203