Structural Features Of The Fairway Basin And Simulation Of Its Accumulation

The Fairway Basin is located on the east side of Lord Howe Ridge in the Southwest Pacific Ocean and the west side of New Caledonia.It is a frontier region for global oil and gas exploration.However,at present,the structural characteristics and accumulation process of each stage of the basin are relatively weak,which limits the further exploration and development of oil and gas resources in the basin.In this paper,based on a large amount of geological,drilling,geophysical and other data from the Tasman sea resource library in New Zealand,the balance profile technology is used to analyze the structural evolution of the basin,and the reservoir formation simulation technology is used to simulate the thermal history of the basin.Through tectonic evolution analysis,except for the lack of a second-stage tectonic reversal stage in the central part of the basin,the structural characteristics of each period in the northern,central,and southern parts of the basin are basically similar:(1)From the Early Cretaceous to the Late Cretaceous intracontinental rift stage,a large number of normal faults developed in the lower part of the basin,the structure of which is represented by the structural pattern of graben or semi-grain;(2)In the transitional period of fault-depression in the Late Cretaceous,the extension rate of the basin reached its maximum;(3)In the early Eocene depression stage,the sediment thickness in the basin reached the maximum;(4)In the first stage of structural inversion in the late Eocene,the whole fold of the basin was uplifted and the angle was unconformably developed.A large number of diapir structures can be seen in the middle of the basin;(5)From the Eocene to Oligocene thermal subsidence stage,the basin began to accept deposition again;(6)During the Oligocene to Miocene second-stage tectonic reversal stage,as the ridges on both sides of the basin continued to uplift,the two wings of the basin gradually lifted.Both wings were eroded,and a large amount of turbid deposits and deep-sea sludge were imported from the two wings to the center of the basin;(7)In the ocean subsidence stage,a large number of filling seismic reflectors and wedge-shaped seismic reflectors are developed on the west side of the basin,which represents that the filling comes from the ridges on both sides.The simulation results of oil and gas accumulation show that the thermal evolution of the source rocks in the northern part of the Fairway Basin is relatively high.Up to now,the whole is in the stage of late oil generation and wet gas generation.Mid-stage oil;the southern part of the Fairway Basin has been in the late stage of oil production till now.Combined with comprehensive analysis of structural evolution and thermal history simulation results,the northern and southern parts of the Fairway Basin can be used as Class I favorable regions for oil and gas exploration,and the central part of the Fairway Basin can be regarded as Class II favorable regions.