乌马营潜山石炭-二叠系油气成藏条件研究

Study of Petroleum Accumulation Condition of Coal-dyas series in Wumaying Buried Hill

2011年以来,潜山研究从后备战场跃升为大港油田增储的主战场,本文依托于大港油田公司科技项目,开展乌马营潜山石炭-二叠系成藏研究,结论认为:①研究区煤层烃源岩多次重复,煤层厚度累计达30-40m,在沙河街组末期进入生烃高峰,目前Ro已达1.0-1.6%。且距下石盒子组储集砂体近,油气来源充足;②下石盒子组砂体分布稳定,砂层连续出现,最大单层厚度25m,砂岩累计厚度可达100m,us1井下石盒子组取心证实该砂体为特低孔特低渗储层为主,但岩石裂缝较为发育,粒内缝10-100um,具备一定的储集能力,其中研究区中段为逆冲推覆体最高点,有利于油气聚集,晚期正断层发育程度低,下切活动不刷烈,对圈闭的改造较弱,有利于油气的保存。

Since 2011, buried hill research has jumped from backup field to the main field for Dagang oilfield production increase. In this pap er, relying on the science and technology project ofDagang oilfield company, it carries out study of the reservoir forming of coal-dyas series in Wumaying bur- ied hill. Conclusion： ① the source rock of coal bed in study area has many same layers and the coal seam thickness with a total of 30- 40m, besides, it comes to the peak hydrocarbon-generating stage in the end period of Shahejie Formation, presently, the Ro has amounted to 1.0- 1.6%. Furthermore it is near to the sand collection body of lower Shihezi formation and the oil and gas source is sufficient. ② The sand body distrib ution of lower Shihezi formation is stable and the sand layer appears in a row, of which the largest single layer thickness is 25 m and the accumulate d sandstone thickness can be up to 100 m, us1 underground Shihezi Formation, after coring, verifies that the sand body is mainly made up with ultra- low porosity and ultra-low permeability reservoir, but the rock fracture has a better development with the intragranular seam of 10-100 um and it has a certain ability of reservoir, of which the middle area of research area is the hightest point of overthrust nappe and it is beneficial to the oil and gas gathering, besides, the normal fault in late period has a low degree of development, not intensive incised activity, weaker transformation o n entrapment, which is conducive to thepreservation ofoil andgas.