The Analysis Of Complex Fault-block Reservoir Architecture And Remaining Oil Distribution

Ma11fault block in Machang oil field is located in Dongming. Shandong Province, its regional tectonic is a uplift belt in the south of Dongpu Depression, which is part of the Tangma structure, adjacented to a low lying land called Gegangji in the east, bounded by Machang fault in the west. Through30-year development, the study area is currently in high water cut development and adjustment governance phase, because the area belongs to medium permeability complex fault block reservoir, its complex structure and heterogeneity factors and remaining oil distribution has a great impact on digging remaining oil and enhancing oil recovery, a appreciable amount of remaining oil is distributed in long-term water flooding oil deposit in different scales and different forms. In order to improve the development effect and enhance oil recovery, and maintain the continuous high and stable yield of the oil field, block conducted a fine reservoir description, but pay more attention to the study of sedimentary microfacies in early period without no more refined studies of reservoir architecture aspects, so it is necessary to use the method of scale analysis and model fitting according to the analytical method of reservoir architecture for the in-depth exploration of inner structure which can control and impact on the remaining oil distribution of the research area reservoir in middle and later periods of water flooding.On the theory of petroleum geology, sedimentary petrology, logging geology, reservoir geology and development geology and guided by deposition law and deposi-tion model of complex fault block, the author of this paper carefully studies the control action mode of the formation and distribution of the remaining oil with regard to the above questions by fully dissecting the reservoir structure.Take the method of controlling by sedimentary cycle to make stratigraphic division and correlation within the regional scale, starting from the marker bed to divide and co-mpare large sedimentary cycles, then correlate single sand in detail based on the phase transition in the sand groups. The stable marker beds of lower Es₃in study area mainly include1#mudstone in the bottom of Es₃-1sand group, combination markers layer of0#mudstone in the middle and sandstone in the middle and the upper and3#mudstone in the middle of Es₃-3. The assist marked bed is largely2#mudstone in Es₃-2sand group.1#mudstone is about30meters thick, the sandstone are stable development in whole region scale and grouping of sandstone is strong;2#mudstone and massive sand-stone symbol in lower have not stable development, sometimes even come to phase tra-nsition, but can be assist marked bed;3#mudstone is stable marked bed that has stable development and20meters thick, and developed in whole block, the change of indu-ction curve characteristics is little. According to these marked bed, lower Es₃is div-ided into7sand groups, in sequence of S3xl, S3x2, S3x3, S3x4, S3x5, S3x6, S3x7, the key formations are S3x1, S3x2, S3x3, which are divided into12,11,9single sands separately.With hierarchical analysis as the basic research methods of reservoir architecture, dividing multiple layers（single sand body、single genetic sand body、sedimentary rhythm） in isochronous stratigraphic framework to make detailed anatomy of the con-figuration of reservoir in study area by fine cross-well tracing and contrast and etc. methods. The results show that the stacking styles of underwater distributary channel sand bodies in vertical include shallow cut mould, deep cut mould and separated type, the plane distribution styles mainly present banding and continuous flake, and the ban-ding is divided into isolation banding and cutting banding. In a composite underwater distributary channel, a single underwater distributary channel can be identified by in-terdistributary estuary, channel margin, top surface elevation difference, channel size difference four marks. The overlying relations of monosandbodies have many types in study area. At the time of multi stage single sand body superposition, there are four types such as lateral bifurcation, interbedded sandstone and mudstone, thinning out in transverse and false connectivity. Same period monosandbody in a plane shows off two types of horizontal off and thickness mutation. Among them, sand and mud inter-stratification in multi-phase monosandbodies is the most common type of structure in the research area. In the discovery of interlayer of lower Es₃in study area, the litho-logy of interlayer barrier is mainly dark grey mudstone, inter channel mud sedimentary is dominated. The Distribution of lower Es₃-1-4sand group is not stable, its phases are changeable, the thickness is generally0.5-7m; interlayers have less number and general sporadic distribution, thickness are a few centimeters to tens of centimeters, most are less than0.5meters.On the basis of configuration analysis, combined with dynamic reality of lower Es₃in Machang oil field, we can come to the conclusion of the impact of different planar distribution forms of monosandbody in channel on remaining oil. The production efficiency of sheet single sand body is high, development effect is relatively good, inter-sected banding single sand body takes second place, isolated banding is the worst. Composite channel to control the distribution of remaining oil is the main performance of the plane transformation and vertical transformation two modes:plane phase trans-formation impact of swept mode of injection water, even cause poor reservoir water out, which lead to potential remaining oil in the area watered out; vertical transformation will be the formation of interlayer interference, resulting in a low level of water-driven water, even without water-driven and the formation of remaining oil. Single channel configuration （inner rhythm, interlayer） control the distribution of remaining oil is mainly manifested in the remaining oil of positive rhythm and complex rhythms and homogeneous rhythm section is generally enriched in the upper, reverse rhythm appears in the lower. Lower of interlayer is potential remaining oil enrichment area.