Flow Units Study Of Xi25-20Block In Fuyu Oilfield

Fuyu Oilfield lie in Songyuan City, Jilin Province and the structural position is located in the east edge of the central depression zone of the southern songliao basin, and it is in No.3fuyu structural of Fuxin uplifted zone, a high dome anticline by complicated fault.The reservoir belong to the structure sandstone reservoir with middle permeability and middle-high porosity. Quan Ⅳ sequences of Cretaceous system (Fuyu oil layer) is the targets in petroleum development, mainly consists of pink sandstone and fine sandstone. The reservoir distribution is stable. The west25-20blocks, the study area, is located in the West Fuyu Oilfied, and the utilized area is2.83km2, the geological reserves is711.3×104t. Destination mainly include Fuyu reservoir, Quan Ⅳ sequences, characterized by shallow bury, more and thin reservoir, different physical property, pink sandstone and fine sandstone, and4-10sub zones are the main layers. An average porosity is23%, permeability is156×10-3μm2.The distribution of the remaining oil is extremely complex, with strong heterogeneity after the waterflood development for thirty years in the study area, the development situation is severe. Therefore, remaining oil research based on a small layer,in the past, has been unable to meet the needs of the remaining oil prediction and the application of new technologies. We should predict interwell reservoir characteristics of three dimensional space more objectively, in-depth anatomise sand internal configuration of a small layer, research seepage barrier and seepage variation of sand inside and its role in controlling the distribution of remaining oil through the reservoir architecture analysis and3D fine geological modeling of facies controlling, it is the foundation of the next step well network, maximizing the control degree of water flooding in the water injection block and polymer flooding test.lastly, we can get into the more in-depth development adjustment.The paper focus on the identification and division of the seepage barrier on the basis of the basic geological research. Research shows that argillaceous interbeds formed by sedimentation is the main seepage barrier in the flow units study. At the same time, the author has selected five parameters,porosity, permeability, clay content, flow zone index, formation coefficient from porosity, permeability, the ratio between porosity and permeability, net pay thickness, formation coefficient, flow zone index, clay content, median grain diameter, the ratio between net pay thickness and sandstone thickness, etc as the main control parameters for coring wells flow unit division. The results is obvious for different types division of flow units to use FZI method of gray theory divided method in this area. The clustering pedigree chart of core well flow unit is formed by using cluster analysis based on flow unit division method and parameter optimization. Four clustering center has been established to form four types of flow units respectively named flow unit I, flow unit II, flow unit III and flow unit IV. Flow unit I and flow unit II develops mainly in the river channel, flow unit III and flow unit IV develops mainly in the river side and river channel flank. Due to just having a small amount of coring wells in study area, so it is important for unsampled wells of flow unit division. The steps for unsampled wells of flow unit division are as follows. Firstly, do discriminant analysis of flow unit classification results gotten by coring samples clustering analysis to get the explanation and discrimination function of the various types of flow units. Secondly, taking the non-coring well flow unit discriminant parameters into the function can get flow unit type. Five previously determined parameters is selected for the discriminant analysis.On the basis of the above study, take the results of single well flow unit division into the PETREL software to build the3D flow unit model controlled by configuration vertical and microfacies plane, master spatial distribution regularities of flow units. Then, the author has established remaining oil distribution patterns on the basis of well logging interpretation, it has great applicable value for increasing reserves and production value; study shows different flow unit type performs different degree of control functions in reservoir absorbing water and production capability. The relationship between flow unit and remaining oil distribution indicates:Although the bottom water advance faster and the water flooded degree of oil well is generally high,but the remaining oil of flow unit I are still high relative to other types of flow units, especially in the region of the interwell; Relative to flow unit I, flow unit II and flow unit III have more layers not used, which is the key area of remaining oil potential in next step. Although flow unit IV has low degree of used layers, but the original oil saturation and residual oil saturation is low because of the poor physical properties.At present, study on reservoir flow units is a hot spot and difficult thing in fine reservoir description. Now, most blocks at Fuyu of Jilin Oil Field of has entered high water cut stage, the recovery efficiency is relatively low, remaining oil is is scattered as a whole while local relatively concentrated. This study forms a complete set of research methods and ideas on delta flow unit classification and correlation, evaluation and application, deepens the understanding of reservoir heterogeneity in study area, provides the scientific basis to improve recovery efficiency for the development phase, at the same time, it also has important guidance and reference significance for similar reservoir development.