塔河油田中下奥陶统顶面古构造演化及油气关系

奥陶系是塔河油田的主要产层。构造演化及古构造研究认为,中下奥陶统在加里东Ⅱ幕期表现为一北东向较宽缓的鼻凸,高点在现今轮台断裂附近;海西早期构造轴向转为北北西,海西晚期—喜马拉雅早期,表现为一由近北西向、北东向斜坡组成的、轴向为北东向的缓顶式直角状凸起;喜马拉雅晚期到现今,该区受西部应力作用和区域翘倾结果,南部轴线保持呈北东向不变,而北部轴线由西往东迁移,构造高点也由北向南迁移。加里东中晚期构造、岩溶及成岩等作用,为塔河油田第一次油气成藏提供了储集空间;受海西早期构造运动的强烈影响,先期油藏被破坏并在局部地区形成重质油藏,同时为海西晚期的油气充注提供了储集空间;印支期以来,该区的成藏系统主要以整体调整为主。

Paleostructural evolution of Lower-Middle Ordovician top and its relationship with hydrocarbon in Tahe Oil Field

Ordovician is the main hydrocarbon producing reservoir in the Tahe Oil Field.Studies of tectonic evolution and paleostructures indicated that the Middle—Lower Ordovician top was a nose-like convex to the northeast during the 2nd phase of Caledonian Movement.The highest point located around the present Luntai Fracture.During the early Hercynian period,structure axial changed to NNW.From the late Hercynian to the early Himalayan,the study area was a rectangular convex composed of NW and NE oriented slopes and the structure axial was to the northeast.From the late Himalayan till now,influenced by the western stress effect and the regional warping,the southern axial remained unchanged,yet the northern axial changed from west to east,and the highest point migrated from north to south.Tectonic,karst and diagenesis effects during the middle and late Caledonian provided room for the first hydrocarbon accumulation in the Tahe Oil Field.Tectonic movements during the early Hercynian destroyed the original reservoirs and heavy oil reservoirs were formed in some region,providing reservoir room for oil-and-gas filling during the late Hercynian.Since Indosinian,accumulation system of the study area has been adjusting.