Analysis Of Main Controlling Factors Of Hydrocarbon Accumulation In Funing Formation Of Gaoyou Depression

Gaoyou Depression is located in the Dongtai Depression of Subei Basin.Its overall shows a fault-like fault structure that is located in the south of the basin.Taking the Funing formation in Gaoyou Depression as the research object,on the basis of collecting a large number of geological and drilling data,this paper,guided by the theory of petroleum geology and reservoir geology,analyses the tectonic evolution,hydrocarbon source rock characteristics,reservoir characteristics,cover characteristics,transport system and oil and gas migration characteristics in the Funing formation of Gaoyou Depression.The oil and gas enrichment law of the Funing formation in Gaoyou Depression is analyzed,and its hydrocarbon accumulation mechanism is explained,and the main controlling factors of oil and gas accumulation are summarized,which provides reference for the oil and gas exploration in the Gaoyou Depression.It is divided into south faults,deep depression belts and north slopes from south to north according to tectonic units.There are three sets of effective source rocks in this area,that is,the lower part of the Tai2 member,the Fu2 member and Fu4 member.Among them,the upper part of the Fu2 member and the Fu4 member are the effective source rock in the Funing formation,and the Fu1 member and Fu3 member are the favorable reservoirs in the Funing formation.The main factors controlling hydrocarbon accumulation in the study area include the following aspects:(1)The influence of oil and gas accumulation factors(static and dynamic factors)on hydrocarbon accumulation in the study area,of which three sets of hydrocarbon source rocks are developed longitudinally,forming three oil and gas systems in the upper,middle and lower areas to control the reservoir and distribution of oil and gas in this area.The main rocks in the Fu1 member and Fu3 member are mainly sandstone and have good physical property.The favorable reservoirs in the region are mainly divided into two types: the fault type and the broken sand combination type.The first type of conductors is mainly distributed in the front of the rising plate of the fault zone,and the second types are mainly distributed in the broken zone.(2)The subfacies of the delta front of the Fu3 member is widely distributed,and the sandstone content is moderate,which is beneficial to the enrichment and accumulation of oil and gas.At the same time,the physical property of the distributary channel is better than the river mouth bar and the distal bar.The vertical oil layer is mainly distributed in the pure sand body and the better material,and the surface is rich in sand and oil rich.It is characterized by the accumulation of oil and oil bearing blocks on favorable underwater distributary channels;the fu1 section belongs to the river-(fan)delta depositional system,the sand body is developed,the reservoir is buried deep in the Sino-foreign slope,and its physical property is good,and it is a favorable area for oil and gas enrichment.(3)The main controlling factor of the sealing ability of the three or four level fault is the percentage of sandstone in the opposite strata.When the content of sandstone in the disks is less than 18%,the fault is closed well.When the content of sandstone is more than 37%,the fault is not closed;when the content of sandstone is 18% to 37%,the fault is closed to the diversity.