Evaluation of effective carrier system and function on hydrocarbon accumulation in Gaoyou Sag, Subei Basin, China

摘要

Effective carrier system comprises carrier beds which transport hydrocarbons.The spatial and temporal effectiveness of carrier system is identified according to the relevance of hydrocarbon show,hydrocarbon inclusion and sealing ability of fault to hydrocarbons distribution,together with matching relation of activity history of fault and hydrocarbon generation history of source rock.On the basis of the above considerations,transporting ability of effective carrier system can be evaluated using parameters such as fluid potential,porosity and permeability,spatial coefficient of effective pathway as well as activity rate of fault.Additionally,a new concept of "transporting threshold porosity" was proposed.Five styles of effective carrier systems were established in Gaoyou Sag,displaying either layered or zonal distribution characteristics,and transporting time ranges from the sedimentary time of E2d2 to early stage of sanduo uplift.Effective carrier systems can be described to be lowly-efficient and highly-efficient.Major faults (convex or steep fault plane) with activity rate greater than 20 m/Ma and structure ridges of sand layers with spatial coefficient of effective pathway greater than 25% are defined to be highly-efficient carrier beds.Hydrocarbons are concentrated around high-efficient carrier beds and E1 f traps of northern shanian area are predicted to have great potential.