State 16 Block Well Pattern Adaptability Analysis

Recently Zhou16,fault-block reservoir,has been found in the Jizhong area with relatively large production system,abundant reserve scale and good reservoir properties,and high oil testing production.In January,2004 this reservoir was put into practice.At present it has been in the development stage,with production rate only 1.1%,and the recovery rate 15%.One of the urgent problems is how to exploit and develop.This paper aims at the adaptability of well pattern of Zhou16 fault-block reservoir,also provides the scientific support for the later development.The achievements in this paper have been achieved as below:1.Geological characteristics of Zhou 16,fault-block reservoir,have been re-studied with thin-section,cores,well logging,fault modeling and structural modeling.Zhou 16 has the features of fault development,fine grained feldspar sandstone,medium porosity and permeability reservoir,two sets of oil-bearing strata,stratified oil-gas reservoir dominated by lithological-tectonic,different water-oil contact with different series of strata.2.From these two aspects,development and production performance are analyzed.In terms of the characteristics of water flooding,the degree of reservoir production is low,but the characteristics of water flooding is obvious,that is,the effect of the main part is obvious,and with the effect of water flooding gradually getting worse,natural decline rate of this fault-block are dramatically increasing.Through analyzing the effect of injection,planar and profile contradiction are serious,and also there is imbalance in the effect of oil wells.Interlayer contradiction goes bad to worse because of multilayer production.Rules of water cut are different.Casing deformation causes injection imperfect.Sand production is growing.3.Fracture characteristics of the areas are studied and crack types are classified.By doing these studies,the relationships between fracture and lithology,fracture and fault,direction of cracks and the role of these cracks in developing,are figured out.There are cracks in this fault-block reservoir and also this can make some explanation on the part of the development problems.4.The distribution characteristic of residual oil is studied and the remaining oil is contiguous.This residual oil is likely to lie in the high positions of fault planes with loss of leading pays,the areas where well patterns between injection wells and production wells are not perfect,and the regions where the degree of production is low because of interlayer interference.5.The adaptability of well pattern of Zhou16,fault-block reservoir,is evaluated from many aspects,so that reasonable well spacing is 190-250 meters.High positions of major parts of this reservoir can be partial exploited layer by layer,but it is not necessary for most areas.Because oil well is effective in multidirectional,total injection-to-producing-well ratio is 1:2 as well as supplement energy is urgently needed in the local formation of pressure drops.