【作者】 杨晓宁；

【导师】 陈洪德；

【作者基本信息】 成都理工大学 ， 古生物学及地层学， 2004， 博士

【摘要】 英吉苏凹陷位于塔里木盆地东部地区，勘探面积达15×10⁴km^z。该区发育了寒武系-下奥陶统和侏罗系两套烃源岩。最新资源评价结果表明油气资源丰富，石油总资源量为2.7～3.2亿吨，天然气总资源量为1.75～2.94万亿立方米，该区具备形成大中型油气田的资源基础。 英吉苏凹陷英南2井侏罗系油气藏是一个特殊盖层的油气藏。它以致密岩屑砂岩作为油气藏盖层，深部气源是油气藏形成的基础，该区古生界地层具有广泛分布生烃强度较高的烃源岩，烃源岩生烃中心位于致密砂岩下倾方向的深部坳陷之中。侏罗系具有气水倒置（上水、下油气）现象，反映深盆气藏性质。 致密砂岩段沉积环境主要以扇三角洲前缘水下分流河道和扇三角洲泛滥平原辫状河道为主，夹有分流河口砂坝和远砂坝及决口扇等沉积环境。含油气砂岩段主要以三角洲前缘水下分流河道和水下分流河口砂坝沉积微相为主。 致密砂岩盖层形成机理是由于含量较高伊蒙--绿蒙混层粘土（一般大于10％）均匀分布于砂岩孔隙中，较强的成岩压实和胶结作用使伊蒙--绿蒙混层粘土具有网格状结构，使砂岩孔隙变成微孔隙、微孔喉。这种微孔隙、微孔喉具有很高的毛细管压力，并与地层水产生水锁现象，可以使原始渗透性能下降到10^-4～10^-6级别，大大降低砂岩的渗透性，使之成为油气盖层。 侏罗系成岩阶段划分为晚成岩A1阶段，在成岩作用中以压实作用和胶结充填作用为主。致密砂岩段压实减孔量平均为15.95％；胶结减孔量平均为10.87％，压实作用和胶结作用产生的孔隙度损失为26.82％。含油气砂岩段压实减孔量平均为17.19％，胶结减孔量平均为6.43％，压实作用和胶结作用产生的孔隙度损失为23.62％（比致密砂岩段少损失2.82％）。 侏罗系主要目的层储层评价以Ⅱ类为主，次为Ⅲ类储层，Ⅱ类储层占地层45％、Ⅲ类储层占地层25％。英南2井产油气层段平均孔隙度14.4％，平均渗透率17.73×10^-3μm²。 晚期成藏是本区油气发育史的又一特征，英吉苏地区侏罗系储层成岩作用控制油气藏形成。成岩作用中--晚期以后发生的油气成藏事件有效。侏罗系储层经历两次主要油气运移期，燕山晚期和喜山晚期。燕山晚期致密砂岩埋深较浅，致密砂岩盖层未形成，为油气无效聚集期；喜山晚期致密砂岩盖层形成，油气聚集成藏。 在详细研究天然气成藏因素的盖层和储层的成岩一成孔演化的基础上，结合天然气的运移和聚集，建立了该区侏罗系的成岩一成藏模式，认为英吉苏凹陷侏罗系属于具有深成性质的断一盖控制型的晚期成藏模式，气源断层和封盖层的有机配套是天然气藏形成的充分必要条件。其中控源断层是必要条件，而砂质岩盖层的有效性是关键成藏要素，它决定了气藏的分布规模和丰度。通过盖层形成史研究表明，第三纪未期这套砂质岩盖层才开始具备封堵天然气的有效性，即此时期英南2井气藏才开始形成。在平面上，龙口1井和华英参1井明显缺乏良好的盖层而未形成气藏。根据该区的成藏条件和规律，预测维马1井以东、龙口1井和华英参1井以北、英南1井东南等地区是有利的气藏分布区。更多还原

【Abstract】 Yingjishu depression is located in the Easter of Tarim and exploration area amount to 15 X 104km2. There are two sets of source rock, which include Cambrian to Lower Ordovician and Jurassic. The latest resources assessment result indicated that oil-gas resources is plentiful where total petroleum resources is 2.7-3.2 hundred million tons and that of nature gas is 1.75-2.94 X 104 hundred million cubic meter. It shows that there can form middle or large oil-gas field.There is a special cover oil-gas reservoir of Jurassic in Yingnan 2 well in Yinggishu depression and its cover is fine rock scrap and deep gas source is the base of oil-gas forming. Palaeozonic has extensive source rock and the produce center of hydrocarbon is located in deep sag and the fine sandstone down direction. The Jurassic is deep gas reservation and reflected by the feature of the gas and water inversion.Sedimentary environment of the fine sandstone main includes the underwater distributary’s channel of delta frontier, braid channel of flood plain in fan-delta, estuary dam, distal bar and crevasse fan. The environment of sandstone containing oil and gas includes underwater distributary’s channel and estuary dam in the delta frontier. The stronger digenetic and compaction make illite-montmorillonite-chlorite clay occupying in sandstone pore and results in sandstone pore decreasing and the fine sandstone cover formed. This kind of micro-pore has high capillary pressure, and result in stratum water blocking and make the primitive permeate descend to 10-4-10-6 d class rating. So the cap rock formed.The diagenesis stage belonging to Al period of late digenetic and compression, cementation and filling are main diagenesis. The compression-decreasing amount of fine sandstone member is average for 15.95% and cementation pore decreasing member is 10.87%. The loss of pore is 26.82% due to compression and cementation. The compression deceased pore amount of oily sandstone average for 17.19%, and that of cementation is 6.13%. The pore loss controlled by compression andcementation is average for 23.62%.The main target stratum reservoir appreciation in Jurassic system relied on the II type, occupying 45 percent in stratum, the next was the III type reservoir, occupying 25 percent in stratum, The average porosity of the Yingnan 2 well producing hydrocarbon was 14.4 percent, and the average permeability was 17.73 X 10-3 um2.Later accumulation was another character of oil and gas development history in this area, reservoir diagenesis in Jurassic system controlled hydrocarbon reservoir formation in Yingjishu area. Since the middle-late diagensis period, the hydrocarbon accumulation event was effective. Jurassic reservoir experienced two main hydrocarbon migration, they were Later Yanshan period and Later Xihan period. Depth of burial condensation sandstone was shallow, so the condensation cap rock did not format, and the period was hydrocarbon ineffective accumulation period. The condensation cap rock formatted in the Later Xihan period, and hydrocarbon accumulated to be reservoir.Through the study of cap rock formation history, the sandstone cap rock of the Later Tertiary began to have the ability to cap natural gas, for another words; in that period Yingnan 2 well reservoir began to format.In the plat surface, the Longkou 1 well and the Huayingcan 1 well obviously lacked of good cap rock, so they did not format hydrocarbon reservoir. According to accumulation condition and rule in the area, forecasted that in the east of Weima 1 well and in the north of Longkou 1 well and Hueyingcan 1 well and in the east-south of Yingnan 1 well etc. area were prospecting hydrocarbon reservoir distribution area.On basis of above studies, the accumulation factors of natural gas, cap rock, reservoir, diagenesis and pore-forming evolution, combing with the natural gas migration and accumulation. The model of accumulation and diagensis in the area of Yingjishu depression on Jurassic is established, the depression belongs to the control of hypogene break-cov更多还原