Sedimentary Facies Study And The Layer Comparison Of The 2nd Member Of Shuangyang Formation In Chang10 Block Of Changchun Oil Field

Changchun Oilfield Chang 10 block situatesin five star structural belt, Luxiang fault. It is a block-type reservoir monoclinic structure, and the study area is only 0.5km2. Since March in 1988, Chang10 well was eligibleto get the industrial oil flow; so far, oil field development has a 28 year-history. Chang 10 block reservoir is volatile. In the initial stage of development, the production declined rapidly, and the cost of mining increased rapidly and the level of mining increased astheresultof slightly high oilproduction rate and rapid formation pressure drop. In order to ensure the high and stable yield oilfields in urgent need of remaining oil, it is required further object of the interval compared with characteristics of microfacies and small layer deposition, providing the basis for tapping the potential of the work.Chang 10 block has some characteristics with high porosity, permeability, high pore throat ratio, non-uniform reservoirand serious reservoir heterogeneity. Because thesuperimposition type of sand body is not very clear, we know few about sedimentary microfacies of target layers. According to the static data and the application of three-dimensional visualization of structural interpretation, we identifieddatum sedimentary cycle and the fine stratigraphic correlation. Based on the high-resolution sequence stratigraphy theory and small layer comparison method, we studied the sedimentary featuresfor our study area. Taking small layer as unit, we divided and correlated the target layers by high-resolution sequence stratigraphic, and established fine stratigraphic framework. With combination of the changing of periodic cycles and the characteristics of superimposed styles, we identified two cycles 3-grade, five 4-grade cycles. On this basis, we determined five sand groups, 20 layers,and further each small layer was divided into a standard single sand body. Based on predecessors understanding, we identified 14 basic rock types and 13 microfacies, and established logging identification plate and a variety of microfacies logging modes.In Chang 10 block, the main microfacies include river channel, mouth bar, bay channel sedimentation, which constitute the fan delta front and fan delta plain deposit. Ⅴ, Ⅰ is the set of sand group fan delta front deposition, Ⅳ, Ⅲ and Ⅱ sand is a set of fan delta plain. Two double bottom boundary showed a significant increase in the water inlet and the water level of the lake, to reach the top Group Ⅴ sand lake level is the highest point; Then, the lake level decreased in the period of group Ⅳ, and a large number of progressive channel sand bodies were developed. In Ⅲ sand. In the period of the lake level decreased rapidly, the rapid retreat of the shoreline occurred alluvial deposition events, formation of a large number of gravelly braided channel sand body, became the good oil and gas reservoir space. Ⅲ, Ⅱ and Ⅰ sand. In the period of the lake level has been declining, divided into lowstand system tract;, sand groups are divided highstand system tracts.Ⅴ ⅣAccording to the division of the strata, we are able to figure out the type of channel sand bodyandthe superimposed manner of sand body. Moreover, the 2nd member microfacies distribution of Shuangyang was realized clearly. On this base, we can predicate the sand body and provide a theoretical basis for tapping the potential of remaining oil.