Reservoir Evaluation Study Of The Chang 2 Oil Group Of Lu 29 Well Zhi Luo Oil Field

The L29 well area of Zhiluo Oilfield is located in Fu County,Yan'an City,Shaanxi Province,and the L29 well area is located in the northeast of the Zhiluo Oilfield.The exploration area is approximately 100km².The L29 well area belongs to a development zone in the Zhiluo Oilfield.This article is based on the multidisciplinary theory of oil geology and use some Test analysis method contain the core data,thin section identification,scanning electron microscopy,vitrinite reflectance and so on as the basis for the article.Study characteristics of the Chang 2 member of the Yanchang Formation in L29 well field in Zhiluo Oilfield.Fine research result can provide a reliable theoretical basis for the development of water injection behind the study area.According to the signature layer and sedimentary cycle,we first divided the Chang 2reservoir group of Yanchang Formation in L29 well field of Zhiluo Oilfield into three layers of length 2¹,length 2²,and length 2³,and then research on the target layer length 2¹ and length 22.After divided once again,the length 21 is divided into two small layers of length 2^1-1 and 2^1-2,and the length 2² is divided into two small layers of length 2^2-1 and 2^2-2.The structural location of the Zhiluo Oilfield is located in the southeastern part of the slope of northern Shaanxi in the Ordos Basin.The overall structure shape is characterized as a monoclinic slope that is east high west side low.On a single-oblique main structure grid,some low-rise nose structure ridges have developed in both deep and shallow layers.The sedimentary microfacies of the2nd section of this area mainly include distributary channel flanks,diversion bays and distributary channels.In addition,the distributary channel flanks are relatively developed in Chang 2¹,while the distributary channels are relatively developed in Chang 2².According to the core description and the analysis of the rock sheet,we can conclude that the main rock types in the Chang 2 reservoir are medium-grained and fine-grained feldspathic sandstone.Quartz,feldspar,rock debris,and a small amount of interstitial matter are the main components of the debris.According to the analysis on physical properties,we believed that the Chang 2 Member is a low-porosity and low-permeability reservoir,the average porosity of2^1-1 is higher than 12%,the permeability is generally lower than 0.5×10^-3?m²,and the porosity of 2^1-2 is longer than that of long 2^1-1,generally distributed in 12%-14%,permeability is generally lower than 0.6×10^-3?m²;long 2^2-1 porosity is high,basically distributed in 13%-15%,permeability is greater than 1.0×10^-3?m² Long 2^2-2 porosity distribution interval is 12%-14%,permeability is generally between at 0.6×10^-3?m²-1×10^-3?m².It can be concluded that the longest physical property of 2^2-1 in Chang 2 reservoir is the best,followed by 2^1-1.According to the analysis of the mercury intrusion capillary pressure test data,the results show that the Chang 2 Formation reservoir is dominated by small pore and fine throat structure.The diagenetics in the L29 well area is dominated by mechanical compaction,cementation,metasomatism,dissolution and cataclasis.According to the comprehensive analysis of the S%,quartz enlargement level,particle contact type,pore type and other indicators in the I/S,the district 2 is in stage B of the diagenetic stage.Based on layered evaluation criteria,the Chang2 reservoirs in the study area are divided into type I high quality reservoirs,type II medium reservoirs,type III poor reservoirs,and type IV tight reservoirs.In Chang 2 reservoirs,type I reservoirs are relatively developed in long 2^2-1,followed by 2^1-1 in length and 2^2-2 in length.It is basically not developed in long 2^1-2,and the type II reservoir is relatively developed in length2^1-1 and length 2^2-1,followed by long 2^2-2,also developed in the long 2^1-2,the main distribution is sporadic.