The volume of oil and gas in the syncline area of Sanzhao Sag

Songliao Basin

is sizable.It’s hard

however

to make clear the complicated oil-water distribution in Putaohua reservoir

and so far its controlling factors are rarely known.Reservoir types discovered and their distribution patterns were investigated

controlling factors of hydrocarbon accumulation were analyzed

and the main controlling factors of oil-water distribution in the syncline area of the prolific sag were discussed

by using the abundant static data and performance data of the mature development blocks of the oilfield.The results show that (1) oil-water distribution of Putaohua reservoir in the syncline area is controlled by a single trap composed of local structure and single sand body

the oil-water interface of a single trap is unified

but the oil-water distribution patterns vary for different single traps adjacent. (2) In a single trap

the oil-water distribution in the syncline area is controlled by the patterns of hydrocarbon accumulation and superimposition:complex spatial superimposition of single traps with and without hydrocarbons ultimately results in the complexity of hydrocarbon accumulation and oil-water distribution in the syncline area

Sanzhao Sag. (3) The superimposition of traps that are composed of vertically multi-layered and laterally multi-branched single sand bodies and complicated local structures with non-traps is the main controlling factor of oil-water distribution in the syncline area.Therefore

reservoir prediction in the syncline area should begin with the analysis of elements of irregular geologic body controlling hydrocarbon accumulation

that is

the evaluation of faults

single sand bodies and their spatial assemblage.