Comprehensive Evaluation of Braided River Reservoir of E1+2,in Kunbei Oilfield,Qaidam Basin

Author:Chen Gengxin

Supervisor:Zheng Junmao


Degree Year:2016





Kunbei Oilfield is an important breakthrough in the exploration of the Qaidam Basin in recent years and is the magnitude guarantee for the construction of Qinghai Oilfield to be ten-million-ton Plateau oil and gas field.Development and practice in recent years proves that the development of E1+2 reservoir in this area is facing many problems and challenges.Aiming at these problems,this thesis mainly carried out the heterogeneous characteristic analysis,deposition micro-facies,multiple point geo-statistics modeling,Interlayer identification and classification,reservoir classification and productivity evaluation research.The main achievements are as follows:(1)The lower part of Lulehe formation(E1+2)is delta-plain,while the upper part is delta-front.It is a retrogradational type.Distributary channel is narrow strip-like,the underwater distributary channel is wideband-like and the dam is in a lens shape.Combination of dynamic and static methods is used to analyse the connection of sand bodies in the section the statistical parameters of the micro-facies units are obtained.The contact relation of micro-facies has vertical overlap,lateral assembly or lateral segmentation.(3)The spatial distribution and thickness distribution of interlayer in interlayer are described.Divide the interval into 3 levels:ⅠMud barriers,Ⅱmud interlayer andⅢphysical property inter-bed.Ⅱmud interlayer has a relative stable distribution.The remaining oil is enriched up or down it.(3)The production capacity of the 3 categories of reservoir is calculated by the small layer:the main layersⅡ-7+8 contribute 87%and the four second main layers account for 13%.The productivity contribution rate of reservoir-Ⅱis 70%,the reservoir-Ⅰis 24%and the reservoir-Ⅲis 6%The paper has made innovative achievements in the aspects of multi point geological statistics stochastic simulation,three-dimensional productivity evaluation:(1)The sequential conditional simulation with angle revolving and scaling relaxes the requirement for a stationary training image in multipoint simulation,is easy easy to condition and better characterizes the vertical heterogeneity.The model results were consistent with practical production and have the potential to guide effective water-flooding development.Effective application demonstrated the feasibility and practicability of the method.(2)Cluster analysis optimize the reservoir controlling factors.The reservoir is divided into 3 categories and the range of them is determined.Heterogeneous comprehensive characterization parameters Bz and productivity evaluation index model is built by regression fitting of the main control parameters and well logging interpretation,oil testing and production test and analysis of testing data based on 3D attribute model.It can used for quantitative characterization of heterogeneity and productivity.Through the comprehensive analysis and evaluation of reservoir heterogeneity,this paper puts forward that enhancing exploitationreservoirs-II and improving water flood degree of the reservoir III is the development direction of oilfield.The 3D model of production can be directly used for productivity prediction layer by layer and according to the categories.The eara has high production index,in which well network control degree is low.It maybe a potential area.