Development And Adjustment Study At Karamay Formation In Block Erdong Of Karamay Oilfield

The reservoir studied in this study is at Karamay Formation in Block Erdong of Karamay Oilfield,which was discovered in 1956 and subdivided into blocks Erdong1+2,Erdong3+4,and Erdong-5.As of 1997,the water cut in the reservoir reached more than 90%.Since 2005,the Block Erdong has been adjusted to various extents.After adjustment,the water cut in the reservoir has dropped to 78% due to the closure of the old well and the influence of the adjustment well.At present,the water-flooded condition of the reservoir and the its remaining oil distribution are quite complex.In order to further adjust the reservoir,the water-flooded condition of the reservoir and the remaining oil distribution in different regions of the reservoir need to be studied in combination with the understanding of reservoir geology.Based on the understanding of reservoir geology and combined with the analysis of steam entry & liquid-producing profile data,this study has carried out qualitative analysis and quantitative multi-parameter interpretation of flooded reservoirs for adjustment wells,and has split the production and injection of each single layer stage by stage by using reservoir engineering method to complete the flooded plan of all single layers,then analyzes the flooding rule and characteristics of each single layer,and finally quantitatively implements the remaining oil reservoir distribution in different areas of Block Erdong Karamay Formation reservoir by combining with numerical simulation methods.Through the research,the following main understandings and achievements have been achieved:(1)Using the logging data of new wells combined with such data as coring and production performance,the interpretation chart of water-flooded reservoirs is established to explain their water-flooded degree in different areas,and the result shows that the remaining oil in this area is mainly distributed in the main oil-bearing single layers.(2)The remaining oil distribution in this area is studied by means of reservoir engineering and numerical simulation,etc.It is determined that the north-central part of Block 1+2 and the northwest part of Block 3+4 are the remaining oil enrichment areas.(3)By comprehensively analyzing the remaining oil distribution characteristics through the interpretation of water-flooded reservoirs as well as the steam entry & liquid-producing profile data,the remaining oil and water-flooded conditions of single renewal wells and the remaining oil distribution between wells and in the plane can be analyzed.The remaining oil is analyzed by reservoir engineering method,which is a semi-quantitative analysis method.The study of remaining oil by using numerical simulation method is a quantitative method.Because the development process of the project area is fairly long and the reservoir heterogeneity is strong,there is the problem of inaccurate permeability adjustment in the fitting process,and there is also deviation in the accuracy of numerical simulation.Therefore,the numerical simulation method is used in combination with the reservoir engineering method and verified with the interpretation results of water-flooded reservoirs and the steam entry & liquid-producing profile data,thus improving the reliability of the numerical simulation.(4)Combined with the effect evaluation of the previous adjustment scheme,the development index of the adjusted reservoirs is optimized.It is considered that the target horizons for this adjustment are oil reservoirs above S7^3-2,and the 180 m interval inverted seven spot method well pattern is adopted for adjustment wells and renewal wells.After adjustment,the reasonable formation pressure is 9.0 MPa and the reasonable injection-production ratio is 1.1,etc.