The Research On Sedimentation Types And Heterogeneity Description Of Exo-front Facies Sand Body In Xingnan Development Area

The production of Xingnan development area of DaQing oilfield has entered into the later period of high water cut development, main target of the third waterflood infill regulation are usable thin poor zone and useless reservoir in delta exo-front facies. Previously, the method of describing exo-front facies sand body is marking off three relative homogeneous cells according to thickness:main thin sand, non-main thin sand, useless reservoir. That doesn't reflect totally ture sedimentary origin of sand body, and we find noncoincident situation between dynamic state and static state in development and application of oilfield. While, the systematic research has not been done for heterogeneity of the kind of reservoir, and perfect researchful method has not been formed. The theme does research on the plane origins of the sand and vertical sediment evolution rules, thereby plane, intraformational, interformational heterogeneous characters of reservoirs are researched, which provides technical support for oilfield development.In the article, taking coring materials as the foundation, on the basis of researches on the characters of sand lithology, rhythm, bedding and logs, the relationships between lectric nature and lithology of different facies have been confirmed, and five electrofacies patterns such as underwater distributary channel, offshore bar, distal bar, sand sheet, inter-sheet mud have been established. By distinguishing facies for every well and plane combination researches, we sum up that sand origins in the plane involve four species:non-stable exo-front facies sand sheet, offshore bar exo-front facies sand sheet, distal bar exo-front facies sand sheet, stable exo-front facies sand sheet. According to vegetal characters and scales of the sand, we have deeper acquaintance with vertical sediment evolution rules.By statistics, analysis and researches for reservoir parameters such as the proportion of sand thickness in reservoir thickness, permeability, permeability contrast, vegetation state of interlayers, a suit of symptomatic method for plane, intraformational,. interformational heterogeneous characters of reservoirs has been formed. A suit of fine reservoir description method for exo-front facies sand body in Xingnan development area has been formed, which consummates fine reservoir description technology about the kind of sand in DaQing oilfield. Applying the research result, we instruct third infill wells layer system zonation of Xing-9,Xing-10 areas in Xingnan development area which take exo-front facies sand body as intended zone digging potence, drawing up perforating schemes, choosing self-contained treatings for digging potence such as reperforating or fracturing for exo-front facies sand body in Xingnan development area, which result in good economic benefits.