海拉尔盆地油气分布规律及下步勘探方向

Law of Oil and gas Distribution in Hailaer Basin and Orientation for Exploration at Next Stage

海拉尔盆地是叠置于内蒙—大兴安岭古生代造山带上的中生代、新生代盆地。该盆地由北东向断裂控制的多个相对独立的断陷群组成,盆地内主要为下白垩统地层, 即兴安岭群、铜钵庙组、南屯组、大磨拐河组、伊敏组。铜钵庙组、南屯组和大磨拐河组发育了三套烃源岩,烃源岩厚度较大,有机质含量高。储层类型主要包括基岩风化壳、砂岩、凝灰质砂岩和砾岩。低水位体系域形成的低水位扇和低水位楔,以及高水位体系域形成的扇三角洲砂体为油气的主要储层。在大磨拐河组区域盖层下,发育了多套生储盖组合。纵向上油气主要富集在不整合面上下,形成断块、断层—岩性、岩性和潜山油气藏四大类油气藏,平面上油气主要集中在主生油凹槽及周边的几个断裂带上,扭动断裂带是油气聚集的有利区带。

Hailaer Basin is the Mesozoic and Cenozoic basin located in the Paleozoic orogenic belt in Inner Mongolia-Daxing anling area. This basin is composed of a number of relatively independent rift groups controlled by the fault of northeastern direction. The basin mainly has Lower Cretaceous strata, namely Xing anling Group, Tongbomiao Formation, Nantun Formation, Damoguaihe Formation andYimin Formation. Three sets of hydrocarbon source rock, with a large thickness and a high content of organic matter, developed in Tongbomiao Formation, Nantun Formation and Damoguaihe Formation. The types of reservoirs main include base rock weathering crust, sandstone, tuffaceous sandstone and conglomerate.The low stand fan caused by the low stand systems tracts and the fan delta sand body caused by the high stand systems tracts are the main oil and gas reservoirs. A number of source-reservoir-caprock assemblages developed under the regional cap rock of Damoguaihe Formation. Vertically, the oil and gas are abundant mainly above and below the unconformity surface, shaping the oil and gas reservoirs of four types-faulted block, fault-lithologic, lithologic and buried hill. Horizontally, the oil and gas are abundant mainly the source groove and the nearby fault belts. The twisted fault belts are the favorable zones for oil and gas accumulation.