Reservoir Discription And Remaining Oil Distribution Of Gu133 Block In Karamay Oilfield

Gu 133 Block is located in the 4-2 district of Karamay oilfield,where the geological condition is complicated and the remaining oil distribution and controlling factors are not clear according to the geological features and production test data.This paper has integrated data set including core,wire-line log,laboratory analysis,production performance and etc.,and adopted the high resolution sequence stratigraphic theory,reservoir architecture analysis method,reservoir engineering and reservoir numerical simulation to analyze the regionally geological features,remaining oil distribution and its controlling factors of heavy oil after hot water drive and steam huff and puff.The major understandings and conclusions are as follows:1.The cycle-thickness correlation method and high-resolution sequence stratigraphy division and correlation principle were adopted to divide the Kexia formation into two sand groups of S₆、S₇ which were further subdivided into 14 small layers.The main geological structure is a relieved hummocky anticline.2.On the basis of the previous sedimentary facies study,the ideas of formation hierarchy analysis and the recovery process,the viewpoint of reservoir architecture units typing and classification scheme for the local sedimentary facies is put forward including braided river,meandering river and alluvial fan etc.,where the conceptions of top bar and core bar for the braid river are proposed.3.The vertical and plane dual geological trending constraint methods are applied on model when building the facies model and it is then used to constrain the property model.The STOIIP is treated as a quantified parameter of uncertainty analysis to design quantitative experiment and conduct uncertainty analysis on model.The Monte Carlo is used to calculate P10,P50 and P90 and perform sensitivity analysis.Different stochastic probability models are ranked and the best optimized one is subjected to upscaling.4.From the geological and reservoir engineering perspectives,the controlling factors for the remaining oil is analyzed.The top bar,core bar and braided river channel in the braid river sedimentary facies system are easy to accumulate remaining oil,while in the meandering river facies system the point bar has the potential.Additionally,in the foot fan facies the sides of the main channel and the edge of beach,as well as the sides of the flow ditch and the edge of sandbar in the middle fan facies are found to be potential for remaining oil accumulation.Base on the material balance method,the remaining oil distribution is studied.Its controlling effect was verified being compared with the analysis of reservoir architecture.By applying reservoir numerical simulation,fine historical matching is studied to understand the possible influences on the remaining oil.The well network,oil viscosity,strength of steam injection and steam huff and puff heating radius are concluded to be the main controlling factors of the remaining oil in this area.5.In order to figure out the approaches to exploit the remaining oil,the numerical simulation method was used to compare results of different development plan,suggesting converting the multi-round steam huff and puff to the steam flooding method.Based on inverted five-spot infill well pattern,the recovery factor is expected to raise 2.29%.This paper derives from production issues of Gu133 block and then be applied back to the production projects,which provides the geological basis for the EOR of this oilfield and forms the fine reservoir description technique suitable to this type of reservoir.