Preliminary analysis of sedimentary characteristics and facies model of M-II layer in Kazakhstan Oilfield A

Abstract

The lithologic melange accumulation of areskum formation in akshabluk area is one of the key strata in exploration. Its basement inheritance controls the whole process of Jurassic sedimentation, and the filling and leveling gradually reduces the terrain elevation difference; After the late Jurassic deformation, the flat paleogeomorphology was changed and the deposition of Early Cretaceous strata was controlled. Under the control of marker beds, sedimentary cycles are divided according to the cycle characteristics of logging curves. Under the control of cycle interface (standard layer), according to the cyclicity of logging curve (GR), combined with core and seismic data, it is divided step by step according to the cycle level, from large to small, that is, it is divided step by step according to “oil bearing series → oil reservoir group → small layer → sedimentary unit”, and a layered system is established. Vertically, M-I and M-II groups are developed from bottom to top. M-II group is divided into m-ii-1 and m-ii-2. M - II - 1 is subdivided into four sub layers: m - Ⅱ - 1A, M - II - 1B, M - II - 1c and M - II - 1D. Based on the comprehensive analysis of sedimentary background and paleostructural characteristics, according to the sedimentary location and sedimentary environment of oilfield a, and referring to core data and seismic data, it is determined that oilfield a develops three sedimentary facies: alluvial fan facies, fluvial facies and lacustrine facies. According to the seismic attribute slice and logging data, predict the sandstone thickness contour map of each sedimentary unit, divide the single well logging facies, study and divide the sedimentary subfacies and sedimentary microfacies according to the sedimentary model.