The Research On Well Pattern Optimization Of Fuyu Reservoir Of Yuan241 Block Of Zhaoyuan Oilfield In Songliao Basin

With the rapid development of China’s national economy,the demand for oil continues to grow.Up to now,the monthly crude oil imports have surpassed the United States,ranking first in the world.In China,nearly 46%of oil and gas belongs to low-grade resources with low permeability.The development and utilization of low-penetration oil and gas resources is of strategic importance to ensure the sustainable development of oil and gas in China.Yuan 241 block of Zhaoyuan,located in Zhaoyuan County,Daqing City,Heilongjiang Province,is managed and developed by the 10th Oil Production Plant of Daqing Oilfield.The oil layers in this block are mainly distributed in the lower part of the Fuyi oil layer group and the lower part of the Fu Er oil layer group.The Fuyu oil layer has a porosity of 10.9%and a permeability of 0.50mD,which belongs to the ultra-low permeability reservoir.In this paper,the maximum peak amplitude,average amplitude,and root mean square amplitude are used to predict the sand body,and the geostatistics are preferably used for inversion.The results show that the thickness of the sandstone in the Fuyu oil layer in the source 241 block is relatively thin,and the narrow and small river channels are developed.The strips are distributed,the lateral change is fast,the average single well sandstone thickness is 34.1m,and the effective thickness is 6.8m.At the same time,the physical properties,sensitivity and fracture development of the reservoir are studied and described in detail.The analysis of the geological characteristics of this block shows that the horizontal and vertical distribution of the oil layers in this area is mainly controlled by lithology and fault zones.Zhaoyuan Oilfield has two types of reservoirs:fault block reservoirs and fault-lithologic reservoirs.By analyzing the dynamic production data of well groups in adjacent blocks,using formula calculations and analogy methods,it is concluded that the oil recovery intensity of large-scale fracture network fracturing is more than 2.9 times higher than that of conventional fracturing.Through numerical simulation calculation,the conventional elastic recovery rate of this block is 3.2%,and the recovery rate of dissolved gas flooding is 9.5%.Combining the well pattern and the direction of artificial fracturing fractures and the development of sand bodies,the reservoir engineering design is carried out for this block.1.According to the reservoir characteristics of the block,it is determined that the development target layer of block yuan241 is Fuyu oil layer,which mainly develops oil layers of group F I and group F II.The sedimentary conditions and properties of the oil layer are basically the same,so a set of development layer series is adopted for development.2.The median permeability of the block is 0.5mD,and the bound water saturation and residual oil saturation are high.It is not suitable for the waterflooding development method,and the development method of elastic mining is adopted.3.Since the area does not have the conditions for self injection mining,it is recommended to adopt the mechanical lifting method for mining and the conventional infrastructure construction method for the ground.4.The oil layer in this block has many development layers,scattered distribution,poor physical properties and tightness,and the main oil layer development is not obvious.The choice of vertical well development,combined with large-scale fracture network fracturing,is conducive to improving The overall utilization of reserves.5.The economic limit well spacing is 375m,the economic limit production of a single well in the Fuyu oil layer of the proposed well area is 2.0t/d,and the lower limit of the effective thickness is6.6m.6.The well array direction shall be parallel to the fracture direction as much as possible,and the well array direction shall be NE90°with a 500m×300m diamond pattern.7.According to different types of reservoirs,different fracturing scales are used,the main sand body,the fracture pattern scale is 450m×270m,and the design penetration ratio is 0.9~0.95,the half length of the crack is controlled at 200m~230m,the scale of the non-principal sand body fracture network is 300m×180m,the design penetration ratio is 0.5~0.6,the half length of the crack is controlled at120m~150m,and the sand adding strength is 15.0m~3/m,Sand-liquid ratio is 1:24.8.The 15 years’development index is predicted and the risk analysis is carried out.