3D Reconstruction Of Flume Sedimentary Experiment Results And Modeling Algorithm Comparison

The N gas field is a large-scale low-permeability gas field in the East China Sea.The thickness of the three gas reservoirs(gas layers)that have been discovered is more than 100 meters,the total gas reservoir thickness is over 400 meters,and the unobstructed flow of exploration wells is 3.08 million square meters per day.The trap area is 30km~2~51km~2,and the trap range is 210~276 m,which has good development prospects.However,its underground reservoirs are characterized by extremely low gas permeability and strong heterogeneity.At present,there are only four well.There still have lots work to de on aspect of research.It is urgent to carry out gas reservoir geological research.Research on the heterogeneity of underground reservoirs has always been a hot and difficult point in petroleum geology.The nature and characteristics of the underground reservoir itself at each location are determined;but the underground reservoir is very complex,it is a combination of various geological processes(sedimentation,diagenesis and tectonic action)The product,the spatial variation of its internal reservoir configuration and reservoir parameters is very complicated,and in the reservoir characterization,because the data used to describe the reservoir is always incomplete,it is difficult to grasp at any scale.The reliable characteristics or properties of the reservoir,especially for terrestrial reservoirs with poor continuity and heterogeneity,are more difficult to accurately characterize the reservoir.The detailed 3D geological models facilitate the characterization of these heterogeneous reservoir property parameters.Taking this target as the research direction,the simulation experiment of the sink sediment for the study area is carried out;the simulation experiment of the sink sediment provides an intuitive and effective means for studying the formation,distribution and evolution of sand-bodies.The simulation results are usually sliced in two dimensions,and the two-dimensional slices are used to study the distribution of sand-bodies in three dimensions.In order to study the distribution law of sand-body directly in three-dimensional space and better predict the heterogeneity of reservoir,this paper proposes a three-dimensional reconstruction of sand-body based on two-dimensional slice simulation of sediment deposition under dual source conditions.Based on this method,virtual wells are used for inter-well prediction,and different well spacings are thinned.Different modeling algorithms are used to simulate and compare the simulation results of 3D reconstruction under different well spacings.The specific experimental process is as follows:Firstly,based on the background of the geological data of the study area,the simulation experiment of the sink sedimentation is carried out.After the sedimentation simulation experiment,the simulated sand-body of the sink sediment is photographed in high precision,and the experimental two-dimensional cross-sectional image is obtained.The coordinate modeling of the acquired two-dimensional cross-sectional image is performed by using commercial modeling software,and then the identified sand-body is digitized.Using the digitized results as conditional data,a three-dimensional reconstruction of the sand-body is performed using a modeling algorithm.Based on the digitalized profile after3D reconstruction,the virtual well is set up,the different wells are drilled to compare the wells,and the different modeling algorithms are used to simulate and compare the simulation results.The results show that the model after three-dimensional reconstruction based on the two-dimensional cross-sectional image of the sink sediment simulation experiment is consistent with the geological features of the study area,and better reproduces the shape and distribution characteristics of the sand-body in three-dimensional space in different source directions.It provides a reference for the prediction of the distribution of sand-bodies in underground reservoirs.Under the condition of complete 2D profile data,insert virtual wells for interwell prediction.Compared with the 3D reconstruction model,the larger the well spacing,the worse the simulation effect,the smaller the well spacing,the better the simulation effect.Sequentially indicating the simulation algorithm and the truncated Gaussian simulation algorithm have better simulation effects than the three-dimensional reconstruction of the sand--body.