Hydrodynamic Geological Effect During The Waterflooding Of Seriously Heterogeneous Reservoirs And4-D Geological Model

Hu12Block of Huzhuangji oilfield is a typical serious heterogeneity reservoir.The hydrodynamic geology effect was studied by using the combined method of theexperimental research and production analysis. A4-D geological model wasestablished.A nine-order classification scheme was proposed to analyze the architectureelements of Es3reservoir of Huzhuangji oilfield, and this scheme is suitable to thescheme of stratigraphic division. Research results indicate that all thick sandbodieshave actually been superimposed by multiphase subaqueous distributary channels,which can be divided by erosional surface, argillaceous or calcic constructionalsurfaces. Thick sandbodies and the channel sandbodies thought to be flakydistribution are vertically superimposed and laterally connected by single sandbodies.Many chanelling paths had formed during long term production. Based on thestatic parameters, production performances and test data, a kind of quantitativemethod by the integrated discrimination exponent was put forward to identify thechanneling paths developed area of reservoirs by using commingled injection andproduction. Studies show that channeling paths would have been formed if theintegrated discrimination exponent is bigger. Among the wells, which are connectedby channeling paths, injectors have the characters of low injection pressure and highwater injection rate and the producers have the characters of high liquid producingcapacity and extra water cut.The chemical power of the acidic medium accelerated the dissolution ofplagioclase, and at the same time new kaolin crystals generated and distributed in the small pore throat. The chemical power has less impact on the carbonate minerals. Thephysical power of the injected water caused the reducing of the total content ofargillaceous minerals and the loss of quartz grains including the size from silt to veryfine, further analysis indicated this occured in layers of better physical and channelingpaths developed, and the content of fine-grained sediments in worse physical layersincreased slightly. Waterflood development has resulted in the increase of the largepore-throat, and the improvement of the penetration condition of reservoir. At thesame time, its effect also caused the reduction of the pore throat sorting and theaggravation of micro-heterogeneity of reservoir. From the macroscopic parameterschange of the reservoir, waterflood development caused the average effective porosityreduce by4.63%, while the overall average effective permeability increased by8.93%.As a whole, the physical changes of the different types reservoirs were showing the“Matthew Effect”. The research about hydrodynamic geology effect duringwaterflooding on serious heterogeneity character reservoir can provide a solidfoundation for reservoir management and enhancing oil recovery.Reservoir macroscopic parameters about different reservoir in the variousdevelopment stages have been caculated according the dynamic predicting model.Based on these parameters, a4-D geological model was established by combination ofdeterministic modeling and stochastic modeling approach. These three-dimensionmodels reproduced the physical changes characteristic of the different reservoirs indifferent periods.The remaining oil distribution of H12block was researched by productionperformance analysis. The practice of research result has achieved a better effect.