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海拉尔-塔木察格盆地为典型的裂陷盆地,发育两套区域性盖层:即强烈裂陷阶段和断-坳转化阶段发育的泥质岩盖层(含少量凝灰岩),累积厚度一般为50～120m,单层厚度为20～50m,其间夹1～2m厚的砂岩,大套泥岩连续分布,为质纯的泥质岩盖层.利用自行设计的排替压力仪测试43块泥岩和凝灰岩样品,其值为0.04～10.00MPa,校正到实际埋深的条件,排替压力为0.09～20.01MPa.随着埋藏深度增加,排替压力逐渐增大,与同深度含油的砂岩或砾岩储层排替压力相比大1～10倍.泥岩盖层排替压力及其与同深度含油砂岩或砾岩储层排替压力差在埋深超过1000m后明显增大.盖-储排替压力差决定盖层封闭的最大烃柱高度变化范围为300～2000m,远大于同深度圈闭的幅度,盖层自身不会渗漏.通过乌尔逊凹陷乌20井深浅储层GOI,均一温度和原油成熟度分析,认为大磨拐河组二段油藏为调整早期油藏形成的次生油藏,主要分布在反转构造上.断裂是破坏盖层完整性的主要原因之一,三种类型断层通常造成油气穿越区域性盖层运移:一是正反转断层破坏早期的封闭条件,造成早期聚集油气的调整运移;二是具有剪切型泥岩涂抹结构的断裂,当断距超过泥岩盖层厚度5倍时,泥岩涂抹失去连续性,垂向开启;三是构造反转阶段形成的正断层,具有典型的碎裂结构,容易造成油气垂向运移.裂陷盆地具有典型“断-盖”共控油气富集层位的特征,95%的地质储量受区域性盖层控制,只有5%的油气受开启断层控制,在区域性盖层之上形成次生油气藏.
The Hailar-Tammog Basin is a typical rift basin with two sets of regional caprock: the muddy rock caprock (including a small amount of tuff) developed in the intense rifting stage and the fault-depression conversion stage. The cumulative thickness is generally 50 ~ 120m, single layer thickness of 20 ~ 50m, sandwiched between 1 ~ 2m thick sandstone, large sets of mudstone continuous distribution of pure muddy rock cover.Using self-designed displacement pressure gauge test of 43 mudstone and The tuff samples, whose value is 0.04-10.00 MPa, corrected to the actual buried depth, displacement pressure is 0.09-20.01 MPa.With the increase of burial depth, the displacement pressure is gradually increased, which is similar to that of the same depth sandstone or conglomerate The displacement pressure of reservoirs is 1 ~ 10 times larger than that of the previous ones, and the displacement pressure of mudstone caprock and its displacement pressure difference with that of oil-bearing sandstone or conglomerate with the same depth obviously increases after the depth exceeds 1000m. The pressure difference determines that the capped hydrocarbon column height varies from 300 to 2000 m, which is much larger than that of the same depth trap, and the cap layer itself will not leak through the GOI of the Wu-20 deep and shallow reservoir in the Wuerxun depression, And crude oil maturity analysis, that the second paragraph of the Great Mooguhe Formation reservoir to adjust the formation of early oil reservoir The reservoirs are mainly distributed in the reverse structure.The fault is one of the main reasons that destroy the integrity of the caprock, and the three types of faults usually cause the migration of oil and gas across the caprock: First, the closed conditions of the early and reverse fault damage , Resulting in the early mobilization of oil and gas to mobilize and mobilize. The second is the fault with a shear-type mudstone smear structure. When the fault spacing exceeds 5 times the thickness of the mudstone caprock, the mudstone smears lose continuity and open in the vertical direction. Thirdly, The normal faulting formed by a typical crustal structure is likely to cause vertical migration of oil and gas.The rift basins are characterized by the accumulation of oil and gas reservoirs commonly controlled by “fault-cap”, and 95% of the geological reserves are affected by the regional With caprock control, only 5% of the oil and gas are controlled by an open fault and form secondary reservoirs above the regional caprock.