【作者】 许凤鸣；

【导师】 卢双舫；

【作者基本信息】 大庆石油学院 ， 矿产普查与勘探， 2008， 博士

【摘要】 本文以经典层序地层学和高分辨率层序地层学相结合为理论依据,综合应用地震、测井、录井、岩心等资料,从古生物特征、岩石、矿物特征、地球化学特征、测井曲线响应、地震剖面特征五个方面在古龙地区姚家组一段地层建立了区域上的四级等时层序地层格架。在层序框架控制下的沉积特征和生、储、盖组合特征研究基础上,从构造、沉积、成岩、裂缝、油气的运移聚集几方面与油气藏的关系讨论了古龙地区油气成藏机理,综合分析了成藏主控因素和油气的分布规律,并指明了有利目标。层序研究表明古龙地区姚家组一段地层为松辽盆地二三级层序的低位体系域,层序受构造沉降、气候、古地貌等多重控制,可划分完整的三个四级层序SQ1、SQ2、SQ3,层序界面和体系域界面在古生物特征、岩石、矿物特征、地球化学特征、测井曲线响应、地震剖面特征方面均有规律可循。研究区姚一段层序充填表现为多物源——北部、齐齐哈尔、西部物源,沉积呈环带分布——受盆地边缘环带状坡折带影响,三角洲前缘水下分流河道极为发育——受湖盆可容纳空间控制,席状砂砂层薄,错叠连片,但纵向有夹层泥岩,横向多不联通等几点特点。构造作用研究表明古龙凹陷周边鼻状构造为有利的油气运聚区,尤其龙南背斜处于常家围子向斜和他拉哈向斜之间,而且隆起幅度明显,因此最有利于油气的聚集,勘探实践也证明了这一点。长垣以西系列鼻状构造紧邻生油凹陷,为油气有利的运移指向,但若无断层、岩性等其它条件构成圈闭,油气只能是路过,而聚集于构造位置更高的大庆长垣背斜圈闭之中。断裂在活动期起到通道作用,通过油源断裂的沟通油气运移至储集层,断裂在静止期起封堵作用,一般在断裂拐弯最大处或者断裂交叉处,断裂泥发育,有利于油气的聚集。沉积作用研究表明沉积基准面的变化控制砂体成因类型与空间分布,低水位体系域发育地层超覆圈闭和多类型复合圈闭,水进体系域发育复合岩性圈闭、岩性尖灭圈闭、透镜体圈闭,高位体系域发育岩性上倾尖灭圈闭和透镜体圈闭。在层序地层格架中,三个体系域均可发育有利的储集层,但它们在形成油气藏时的作用和地位却存在着较大的差异。盆地边缘斜坡带发育的坡折区有利于形成地层超覆油气藏、地层不整合油气藏和构造尖灭油气藏;坡折带之下盆地中心部位,有利于形成多类型复合岩性圈闭;研究区南部有利于形成砂岩透镜体岩性圈闭带。成岩作用研究表明本地区次生孔隙形成的主控因素为有机质热解生成有机酸和碳酸溶蚀及大气水淋滤作用,并预测古龙凹陷是次生孔隙发育区。裂缝成因研究表明新站地区储层裂缝主要为构造裂缝,沉积作用控制下的形成的夹于泥岩中的薄砂层是裂缝形成的岩性基础,在区域构造背景下该区的特定构造演化的作用下,最终导致了新站地区葡萄花油层形成裂缝型储层的特征,储层超压的存在是裂缝形成不容忽视的因素。油气运移聚集的主控分析研究表明超压和浮力作用(动力)与毛细管阻力作用(阻力)双重作用下对油气水运移的影响是向斜低孔低渗滞留油藏纯油、向斜斜坡区中孔低渗半滞留油藏油水同层和构造高部位中孔中渗油水重力分异的关键。通过以上古龙地区油气藏形成机理研究可以看出控制本区油藏类型、油气分布的主要因素有四个方面:1)砂体类型及空间叠置决定了古龙地区油藏的空间展布及石油充满程度;2)储层类型对油气的控制作用;3)构造类型及所处位置对油气的控制作用;4)断层排列及演化对油气的控制作用。将古龙凹陷姚一段葡萄花油层由凹陷周边到凹陷内划分为四个油藏带即鼻状构造油藏带、他拉哈-英台构造-岩性复合油藏带、古龙-茂兴向斜区复杂岩性油藏带和凹陷斜坡区上倾尖灭-断层岩性油藏带,并指明了有利的地层-岩性有利目标。更多还原

【Abstract】 Adopting the classic and high-solution sequence stratigraphy as theoretical basis, this dissertation uses the seismic, well log, geologic log and core data to establish four-order regional chronostratigraphic framework by the characteristics of palaeotology, petrology, mineralogy, geochemistry, well logging response and seismic section in K2y1 in Gulong Region. Based on the study of sedimentary feature and source-reservoir-cap rock association within sequence framework, the dissertation discusses the formation mechanism of oil and gas reservoir through the relationship between the structure, sedimentary, diagenesis, fracture, migration and the reservoir, and comprehensively analyzes the main controlling factors of reservoir formation and petroleum distribution, and points to the favorable targets.Sequence research shows that the K2y1 layer in Gulong Region belongs to the LST (Lower System Tract) 2nd and/or 3rd-order sequence in Songliao Basin, which is controlled by tectonic subsidence, palaeoclimate and palaeogeomorphology etc. and can be divided into three 4th-order sequences SQ1, SQ2, SQ3, and the sequence boundary and system boundary can be determined by palaetologic, petrologic, mineral, geochemical, well logging response and seismic section features. The K2y1 sequence in research zone is filled by multi-provenance from the north, Qiqihaer and the west, the ring distribution of deposits is controlled by the ring slope-break zone at the edge of the basin. The underwater distributary channels of delta front are very well developed which is controlled by the accommodation of the lacustrine basin, but the thin blanket sands are almost unconnected laterally with interlayered mudstone vertically.Structure research shows that the nosing structures around Gulong Sag are the most favorable zone for oil and gas migration and accumulation, especially Longnan Anticline, located between Changjiaweizi Syncline and Talaha Syncline with high uplift, is favorable to the petroleum migration and accumulation, which has been confirmed by the exploration practices. A series of nosing structures on the west of Daqing Placanticline are close to the petroleum generative depression and considered as the favorable migration direction, but if there are not necessary factors forming the traps, such as fault and lithology, the oil and gas will pass by these nosing structures and accumulates in the structure traps upon the higher placanticline. The fracture serves as the channel in active period through which the oil and gas can migrate from the source rock to the reservoir, vise versa in repose period. Fault clay in the fracture turning and/ or in the intersection of fractures is favorable to the oil and gas accumulation.Sedimentary research shows that the change of base level of deposition controls the genetic type of sand bodies and their distribution in space, and that in LST develop stratigraphic overlap trap and sorts of combination traps, and in TST (Transgressive System Tract) develop composite lithologic trap, lithologic pinchout trap and lens trap, and in HST (High System Tract) lithologic upward pinchout trap and lens trap. Of all the three system tracts in the sequence stratigraphic framework develop the favorable reservoir, but they play different roles during the process of oil and gas reservoir formation. In the slope-break zone at the edge of basin is prone to form the stratigraphic overlap reservoir, stratigraphic unconformity reservoir and structural pinchout reservoir, while in the center of basin below the slope-break zone develop types of composite lithologic traps and in south of the research zone is the lithologic trap belt composed of sand bodies.Diagenesis research shows that the main controlling factors of secondary porosity in this region are the organic acid generated from organic pyrolysis, carbon acid corrosion and meteoricwater eluviation. Based on the result the dissertation predicts that Gulong Sag is the secondary porosity development area.Fracture research shows that in Xinzhan Region reservoir fracture is structure fracture, and that under the control of deposition the thin sand interlayer within mudstone is the lithologic basis for fracture formation, and that in the tectonic setting the special structural evolution leads to the fractured reservoir formation in Putaohua oil-bearing layer in Xinzhan Region, reservoir overpressure is another important factor in fracture formation.By analyzing the main controlling factors of oil and gas migration and accumulation, the dissertation considers that overpressure + buoyancy (driving force) and capillary force (resistance force) are the key in the migration of oil, gas and water to the pure oil accumulation in occluded oil reservoir with low porosity and permeability in syncline, the oil-water bearing layer formation in semi- occluded oil reservoir with middle porosity and low permeability in the slope of syncline and gravitational differentiation of oil and water in reservoir with middle porosity and permeability in high structure.The above research on the mechanism of oil and gas reservoir formation shows that the main controlling factors of the type of oil and gas reservoir and the distribution of oil and water in space include: (1) the type of sand body and the superposition in space determining the distribution of oil reservoir in space and the degree of oil filling the reservoir in Gulong Region; (2) the type of reservoir; (3) the type of structure and its location; (4) evolution and arrangement of faults. In the end the dissertation divides the K2y1 Putaohua oil-bearing layer in Gulong Sag into four oil reservoir belts from the boundary into the center of the sag—nosing structure reservoir belt, structural-lithologic combination reservoir belt in Talaha-Yingtai Region, complex lithologic reservoir belt in Gulong-Maoxing Syncline and upward pinchout-fault-lithologic reservoir belt in the slope of sag, and also points to the favorable stratigraphic-lithologic targets.更多还原