二连盆地呼仁布其凹陷烃源岩特征及资源潜力评价

Source Rock Characteristics and Resource Potential Evaluation of Hurenbuqi Sag in Erlian Basin

二连盆地呼仁布其凹陷下白垩统巴彦花群发育一套内陆河湖相碎屑岩沉积,东部深洼槽腾格尔组半深-深湖相烃源岩十分发育,岩性以深灰、灰黑色泥岩、页岩为主。有机碳含量大于5.0%,氯仿沥青A含量大于0.5%,总烃含量大于1500×10-6.有机质类型以Ⅱ1腐殖腐泥型为主,镜质体反射率平均0.57%,热演化处于低成熟的生油阶段。生油潜率大于60mg/g.利用氯仿沥青A法计算,呼仁布其凹陷总生油量为38.5109×108t,总资源量为1.8524×108t,表明具有一定的油气资源和勘探潜力。其中腾格尔组一段资源量最大为1.5739×108t,是勘探主要目的层。区域上南、北次凹资源量占到总资源量的89%,为勘探重点地区。

The Bayanhua group of the Lower Cretaceous in the Hurenbuqi sag of Erlian basin develops a set of deposit of inland rive-lake facies clastic rocks. Semi-deep and deep lacustrine source rocks commonly occur in the Tengge＇er formation in eastern deep trough of the sag, dominated by lithology of dark gray and gray-black mudstone and shale, with the organic carbon content of greater than 5.0%, the chloroform bitumen ＂A＂ of greater than 0.5%, the total hydrocarbon of greater than 1 500 ppm, the type of organic matter is dominated by humosapropelic type （Ⅱ1）, and the vitrinite reflectance averaging 0.57%, indicating the thermal evolution is in low-mature oil-generating stage. The potential oil-generation rate is more than 60 mg/g. The total oil-generating quantity is 38.510 9×10^8 t. The total resource is 1.852 4×10^8t in this sag calculated by means of chlorofrom bitumen ＂A＂ method, indicating it is of a certain of petroleum resource and explorative potentials. Among them, the 1st member of Tengge＇er formation assumes the largest volume of resources of 1.573 9×10^8 t, being the main target for exploration. Regionally, some sub-sags in the south and north have the largest resources accounting for a total resource of 89%, being important areas for exploration.