Research On 3D Architecture Modeling Of Turbidite Reservoir:A Case Study Of Middle Es₃ In He146 Fault Block

Due to the long-term waterflooding,most of Oilfields in eastern China have entered the period of High Water Cut stage,with obvious water flood and complicated distribution of remaining oil,in which the architecture of sand is the mainly problem during oil production.Instead of conventional sedimentary facies study and traditional geological modeling,meticulously architecture modeling is needed in this period.However,the geological modeling methods we commonly used are still defective in characterizing the three-dimensional space distribution of the geologic body.Since the development of the middle part of Es₃ sub-formation in He146 fault blocks of Xianhezhuang Oil Field,the distribution and internal architecture of the turbidite sand body is still not clear which caused the low recovery degree of reserves and injection-production contradictions,needing reservoir architecture analysis.This paper is researching on architecture 3D modeling method of turbidite reservoir in the case of middle Es₃ in He146 fault block of Xianhezhuang Oil Field,in order to establish a set of turbidite reservoir architecture model suitable for the study area,for the subsequent reservoir numerical simulation and the study on the distribution of remaining oil.The main guiding ideology of reservoir architecture analysis is scale analysis and model fitting.The surface of reservoir architecture and sequence stratigraphy,both of which are time-scale surface,can establish connection with each other,which is helpful for dividing the high level architecture interface of turbidite reservoir.Though fine dissection of turbidite reservoir in the study area based on the study of regional sequence stratigraphy and sedimentary system,this paper analyzed the different level of reservoir architecture step by step and identified the low level of architecture units.Finally,this paper established the 3D geological model of turbidite reservoir architecture by level using suitable modeling methods based on the characteristics of the study area.The key to architecture modeling is characterization the three-dimensional space distribution of different level of architecture units,compared with conventional geological modeling.The ideology of the architecture modeling methods we proposed is hierarchical constraint,modeling by level and combine with several modeling methods.What's more,the object-based modeling algorithm is improved on this research based on the needed of the study area.The geological study showed that there are two type of turbidite sediment in the area,one is turbidite without channel,and the other is turbidite with supply channel.The former is developed in No.2 and No.3 sand group in Es₃,and the latter is developed on the top of No.4 sand group in Es₃.Different modeling methods are used for different type of turbidite.For the turbidite without channel,deterministic modeling method is used for 4^thh architecture units,multi-point statistics simulation with various constraints for 5^thh architecture units,and Turbidite Simulation Program we developed for 6^th architecture units,which is based on the probability body of topography.For the turbidite with supply channel,we adopted deterministic modeling method for 4^th composite channel units,and adaptive channel modeling with 4^th level constraints for 5^th single channel units.Finally,we established the petrophysical models with the control of architecture units and the constraint of probability body for property modeling.The models we established are conducted through several of model test methods,whose results demonstrate that the geological models are reliable.And the architecture modeling methods we adopted are suitable for the study area compared with conventional geological modeling methods.