Reservoir Architecture Characteristics Of Xinglongtai-Ⅱ Reservoir Group, In Du 84 Fault Block, Liaohe Depression

Fan delta reservoir is more or less found in the Meso-Cenozoic Basins of China, which has important significance to oil and gas development. Taking the Xinglongtai Ⅱ Reservoir Group of the Du 84 block, Shuguang Oilfield, Liaohe Depression as a case, under the condition of dense well pattern, this paper mainly deals with the hierarchy of internal architecture and the reservoir architecture characteristics of fan delta front.By using the method of scale analysis, the architectural surfaces and elements are precisely anatomized. To further demonstrate its depositional complexity, four orders of architectural surfaces in the fan delta front. The sixth bounding surface is the boundary of multiple braided channel and mouth bar. The fifth bounding surface is the boundary of synchronization braided channel complex(or mouth bar complex,or braided channel-mouth bar complex). The mud structure surfaces and the pebbly sandstones between two stages of channel sand bodies are the two types of the fourth surfaces. The muddy intercalation in the single channel are the third surfaces. Two kinds of the sixth architectural elements are divided into the fan delta front, which are braided-stream belt and sheet-flood belt. The braided-stream belt can be divided into two kinds of fifth architectural elements, which are braided channel and mouth bar.On the basis of the establishment of the hierarchy of architecture surfaces and elements, further analysis is developed in the Braided channel sand bodies. Following four aspects are involved. Firstly, five kinds of electrofacies are summed up, which are middle-high amplitude cylinder shape, middle-high amplitude serrated cylinder shape, middle amplitude thin cylinder shape, funnel shape and funnel-cylinder shape combination. Electrofacies show some differences and regularity in different parts of the river. Secondly, six marks of single channel sand body can be identified, which are characteristic of logging curves, the different distance between sand body and top layer of adjacent wells, thick-thin-thick sand bodies association, lateral stacking sand, channel-mouth bar-channel and inter-channel sediments. Thirdly, the sand bodies’ contact style is summarized, the vertical style of which is divided into vertical superimposition, lateral overly, horizontal overlap and isolated distribution, the plane distribution pattern of which is divided into isolated banded form, cross-cutting banded form and flaky form. Fourthly, the single channel scale is determined. Through drawing the sand bodies of the cross section, calculate out the width and the thickness of the clear boundary of sand bodies, and fit formulas of the width and thickness of single channel.