Identification And Architecture Analysis Of Point Bar Deposit In QHD32-6 Oil Field

QHD oilfield is located in the middle of Bohai Bay Basin. It is a large heavy oil fields of fluvial facies. Within the exploration and development in recent 20 years, the workers in the oil field have made a large number of geological research knowledge.In recent years, with many Wells has entered the later period of waterflooding,potentialities and increasing difficulty, the exploration of remaining oil becomes much more difficult. The original geological understanding cannot meet the needs of the further exploration and development. The finer reservoir description of meandering river deposit and point bar will contribute a lot to perfecting flooding producing well network, improving water flooding efficiency, and improving reserves producing degree.Based on the data of QHD3-26 oilfield, this paper uses well-logs and seismic data to divide and correlate the substrata. Based on the interface of substrata, the superimposed style of sand bodies, and log facies, this paper propose the division and correlation method based on log facies. The new method uses the log facies, the difference of elevation and the vertical distribution of single sand body in meandering river deposit to divide the sand body into the single sand layer.In order to draw the precise microfacies map of single sand layer, Seismic attribute, sand thickness data and sand width-to-thickness ratio is used to draw and verify the sand thickness isopach map. Microfacies maps are drawn based on the sand thickness isopach map together with well logs, outcrops and the sedimentary pattern of meandering rivers. distribution of sand bodies. The microfacies patterns can be divided into banding pattern, sheet pattern and the joint banding pattern. The banding pattern is on the transformation surfaces of the rising and falling of datum plane, and the sheet pattern is on the transformation surfaces of the rising and falling of datum plane, and the joint banding pattern is on the process of the rising and falling of datum plane.The identification of point bar is based on the vertical superimposed style and plane combination of sand bodies. By using the predecessors’ experience formula, thescale of point bar and measuring error are calculated. For the point bars with excessive error, reanalyze them, and draw the scale again with more accurate sizes.By the difference of elevation, the difference of well logs, the trend of lateral thinning,the drilling of channel sand body, and the Incision of channel, we can identify the single point bar in vertical distribution in the multiple superimposed sand body of major reservoirs. To verify the accuracy of the single point, we use the production performance data, including the injection and produced data, and the tracer data in each layer.This paper combined the outcrop data, well data, and oil-water dynamic data to do the architecture analysis of point bar. In order to identify the planar distribution of inclined shale layers, this paper utilizes a four-step method:(1) finding the inclined shale layers in well section with core and log data;(2) drawing the inclined shale layers in well section with their calculated occurrence;(3) dotting the intersections of inclined shale layers and the point bar’s top surface;(4) connecting the dots into lines by using the calculated occurrence again.Based on the accurate identification of point bar, facies model, porosity model, permeability model, and oil saturation model are build. The effects of inclination, Spacing, and dissected depth on the residual oil distribution and oil and water movement are also discussed on this paper.