Identification And Characterization Of Barrier And Intercalation Of Xing? Reservoir Formation In Du 84 Block,liaohe Depression

Shu 1 district Du 84 block is located in the middle of west slope in west Liaohe Depression.It is a homocline clamped by several faults.3 heavy oil reservoirs with great thicknessdevelop vertically: Guantao reservoir,Xinglongtai reservoir Xing I-IV formation and Xing VI formation.There are few researches focus on the characteristics of interlayer in this area.But it is necessary to study them,since its type and distribution has an important influence on oilfield SAGD development.For this purpose,this paper studies interlayer in Xing I formation.Coring data of 18 cored wells are analyzed at first.Sequence stratigraphy boundaries are identified based on logging data,thus Xing I formation is divided into 4 single layers.The research section developed in fan delta front sedimentary environment,and 6 micro facies are further identified: distributary channel,underwater distributary channel,mouth bar,interdistributary bay,shore-shallow lacustrine and sheet sand.Combined with permeability data and research experience,rock composition of core impervious bed is studied.With the property and electrical analysis for different kinds of impervious beds,4 types of interlayer are carried out: muddy barrier,muddy intercalation,physical barrier and physical intercalation.Detailed interpretation of 57 wells in main profile and logging curve intersection has been studied.Then criterion of identification and logging template of interlayer has been established based on porosity and permeability,and has been applied in the whole research area.In the help of interlayer distribution profiles and plane maps,the relationship between interlayer and sedimentary facies has been studied.At last,the development characteristics of different kinds of interlayer are clarified.The sedimentary environment controls the development of interlayer.Muddy barrier controlled by lacustrine transgression develops well in XI 1-1 and 1-2 layers,and reaches a maximum thickness of 10 m at the top of layer.Muddy intercalation is the mud deposits within a contemporaneous channel sand body,and it develops well in XI 1-2 while equally in other layers.Physical interlayer can form in following 3 circumstances: fine-grained sediment above channel sand body because of the rise of lake level and the migration of channel,strandeddeposits above erosion surface owing to the weakened hydrodynamic force,bottom sediment caused by fluvial incision of later channel.Physical interlayer basically develop along channels.It mainly develops in XI 2-1 and 2-2 layer,and has a poor overall continuity with an average thickness of 0.5-1m.