Study On Distribution Of Fluid System Of Donghe Sandstone Reservoir In Hudson Oilfield

The Donghe sandstone reservoir of Hudson Oilfield is China's first 100-ton-ton,fully-integrated,marine sandstone reservoir with a reservoir thickness of less than 30 meters and a burial depth of more than 5,000 meters.At present,it has entered the middle and late development period,with a total moisture content of 82.4%.The distribution relationship of oil and water is complex,the development of reservoir bottom water,sand body connectivity is difficult to describe,and the stacking law is complex.Due to the differences in injection waterflood characteristics and production dynamic characteristics of the reservoirs in each block,together with the different types of wells,the complexities of the injection and production wells groups resulted in differences in overall reservoir fluid changes.In response to this problem,the Donghe sandstone reservoir area is divided into four lithological areas: Northwest,Central,Southwest,and Southeast.By analyzing the logging and logging data in each area and combining the basic characteristics of Donghe sandstone reservoir,it was found that the distribution of oil and water in some areas of the reservoir is affected by lithology,so the overall appearance of the reservoir is high in the east,low in the west,and low in the south and high in the north,called stair-like "tilt oil-water interface" phenomenon.Through production dynamic response,the connectivity analysis between wells was performed,and a total of four types of sand body connectivity modes,namely,good connectivity,medium connectivity,weak connectivity,and no connectivity,were defined.The pressures in the central and southeast areas of Hudson Oilfield have decreased more sharply.The natural energy in the southwest area has become stronger and the fluid production capacity has increased.However,the water content has risen rapidly.The water in the northwestern region is relatively strong,but the nature of the crude oil is poor and the water content rises rapidly.After analysis of the characteristics of production and water-cutting changes from well to well,oil wells were classified into four categories: dynamic changeable wells,injection water breakthrough wells,large-scale extraction wells,and water-containing fluctuation wells.The remaining oil is mainly distributed in the 1st and 2nd layers of Donghe sandstone in the longitudinal direction,and the remaining oil reserves gradually decrease with increasing depth.The remaining reserves gradually decrease,and the remaining oil on the plane mainly concentrates in the south area of A4-7H to A4-4H.The type of oil remaining in the reservoir can be controlled mainly by well control,counter fan type and sandwich type control.