苏北盆地金湖凹陷热史与成藏期判识  

Thermal History Reconstruction and Hydrocarbon Accumulation Period Discrimination of Jinhu Depression in Subei Basin

作　　者：李亚军[1] 李儒峰[1] 陈莉琼[2] 宋宁[2] 方晶[3] 

机构地区：[1]中国石油大学,北京102249 [2]中国石油化工股份有限公司江苏油田地质科学研究院,江苏扬州225009 [3]天津师范大学城市与环境科学学院,天津300386

出　　处：《沉积学报》2011年第2期395-401,共7页Acta Sedimentologica Sinica

摘　　要：在镜质体反射率和磷灰石裂变径迹系统测试分析的基础上,对金湖凹陷西斜坡和卞闵杨构造带进行古地温梯度计算和热史恢复。根据镜质体反射率计算出西斜坡的古地温范围介于45.6～128.4℃,古地温梯度为45.5℃/km;卞闵杨构造带古地温为26.4～120.3℃,古地温梯度为42.7℃/km。根据磷灰石裂变径迹计算出西斜坡古地温梯度为40.7℃/km,卞闵杨构造带为45.8℃/km。对比分析得出凹陷内不同构造带均具有古地温梯度大于今地温梯度的规律,西斜坡古地温梯度高于现今10.4～15.2℃/km,卞闵杨构造带古地温梯度高于现今12.4～15.3℃/km。对西斜坡和卞闵杨构造带典型井进行热史模拟,得出古地温梯度随着凹陷地层年代变新而降低,三垛构造事件所导致的抬升剥蚀之前,凹陷已达到最大古地温。成熟度史反映出金湖凹陷埋深在1 000 m处Ro为0.4%,烃源岩进入低熟阶段,在1 900 m处Ro为0.65%,温度达到90℃,烃源岩进入生烃高峰阶段。将金湖凹陷西斜坡典型单井埋藏史—热史与包裹体均一温度综合分析,判识出成藏期介于47～41.5 Ma,确定了三垛期为金湖凹陷主成藏期。Based on the analysis of the vitrinite reflectance and apatite fission track inclusions system testing,we carried out the calculation of paleotemperature gradient and reconstruction of thermal history,and then identified the paleotemperature gradient of west slope and Bianminyang tectonic zone of Jinhu depression.According to the vitrinite reflectance,we calculated that the range of the paleotemperature being between 45.6~128.4℃ and the paleotemperature gradient was 45.5 ℃/km in the west slope,the paleotemperature in Bianminyang tectonic zone was 26.4~120.3℃ and the paleotemperature gradient was 42.7℃/km.According to the apatite fission track,we calculated that the paleotemperature gradient in the west slope was 40.7℃/km,and in Bianminyang tectonic zone was 45.8℃/km.From the comparative analysis with different tectonic zones of Jinhu depression,we concluded a law that the paleo temperature gradient was higher than present-day geothermal gradient,specifically as follows： in the west slope,paleotemperature was 10.4~15.2℃/km higher than the current,and in Bianminyang tectonic zone paleotemperature was 12.4~15.3℃/km higher than the present.By the thermal history modeling of typical wells in west slope and Bianminyang tectonic zone,it could be seen that the paleo-geothermal gradient became lower with the stratigraphical time changed for the new.It shows that the geothermal gradient of K2t^E1f was higher than E2d^Ny.Before the uplift and erosion caused by the Sanduo tectonic events,the paleo-temperature of depression had reached the maximum.The maturity history of depression reflected that the Ro was 0.4% in the depth of 1 000 m of Jinhu depression.The source rock was at the low-mature stage.The Ro was 0.65% in the depth of 1 900 m and the temperature reached 90℃,the hydrocarbon source rocks entered the peak phase.The homogenization temperature of fluid inclusion samples was between 62~93℃ of Well Cui 2 in the west slope.Through the comprehensive analysis of the burial history-thermal history of t

关 键 词：金湖凹陷 地温梯度 古温标参数 热史恢复 成藏期 

分 类 号：TE121.1[石油与天然气工程—油气勘探]