Study On The Identification Of Large Pore Channel In The Later Stage Of Waterflooding In ZN Fault Block Reservoir

The ZN fault block reservoir has entered the high water cut stage,the contradiction between the plane and the layer is especially prominent,and the problem of the large pore channel is serious.The production of the reservoir is difficult to produce,and the effect is poor.Therefore,it is necessary to clearly recognize the development and distribution of the large pore channels of the reservoir,this is the only way to effectively use the three oil recovery technology to improve oil recovery.From the definition,causes,types and aspects of the performance of the four characteristics of the large pore channels are summarized and the present commonly used several channel identification methods are studied,analyzed the recognition principle,their advantages and disadvantages and the applicable conditions.On the other hand,the characteristics of ZN fault block reservoir are studied from two aspects of geological characteristics and development characteristics.The reservoir characteristics and sedimentary characteristics of geological characteristics are studied.In the aspect of development characteristics,the development history,development status and problems of ZN fault block reservoir are studied.Large pore channel and ZN fault block reservoir has a more detailed understanding.The identification of the ZN fault block reservoir is studied from two aspects of plane and vertical.Firstly,a fuzzy comprehensive evaluation method is used to identify the wells with large pore channel in the reservoir plane.According to the static characteristics and dynamic characteristics of ZN fault block reservoir,the average permeability,heterogeneity and effective thickness of the single well are selected as the static identification index of the ZN large pore channel.The daily injection volume,water injection pressure,apparent water absorption index and unit thickness cumulative injection were used as dynamic identification index of water injection well.Select the amount of daily liquid production,moisture content,liquid production strength and the cumulative thickness of the unit as production well dynamic identification indicators.The fuzzy evaluation model of injection well and oil well is constructed.By using the "C++",a "big channel fuzzy judgment system" is developed,which is used in 47 oil or water wells.Three dimensional geological model of reservoir is established.A three-dimensional flow simulation of oil and water was carried out by using RDOS reservoir dynamic analysis system developed for ineffective waterflooding,combined with the longitudinal discriminant parameters of the large pore,the development of the longitudinal large pore channel in the reservoir is studied.Finally,the identification results of the two methods are comprehensively analyzed,and the well pair and layer of ZN fault block reservoir which are most likely to develop large pores are given.The results show that the ZN fault block reservoir develops 13 water wells with large pore channel,accounting for about 68.42%of the total water wells,and there are 17 oil wells with large pore channel,accounting for about 62.96%of the total oil wells.Injection wells Z1275-6,Z1276-5,Z1287-4,ZX1280-3 and oil wells Z1281-3,ZX1287-2 have a number of single sand layer developing large pore channel,they are large pore channel serious wells.On the plane,the large pore channel of ZN fault block reservoir is mainly distributed in the middle of the reservoir.Vertical,mainly distributed in V3,V4,V5 and V8 and other reservoirs main reservoir,large pore channel of V3-1-2,V3-3,V5-2 and V8-2-1 four single sand layers is relatively serious.