Research On Pore Structure Parameters Of Sandstone Based On CT Data

The pore structure of reservoir rock is very complex,so it is very important to study the equivalent pore network model of rock pore structure and micro-scale seepage.The accuracy of its modeling is of utmost importance,for digital core and pore network models serve as the fundamental foundation for microscopic seepage simulation research.Based on Python programming language and CT tomography images,this paper studies the three-dimensional reconstruction of the microscopic pore structure of sandstone,and develops a visual system software platform for analyzing the pore structure of sandstone cores.Based on the established real core digital model,the pore network model equivalent to the digital core is extracted by using the maximum sphere algorithm,and the pore micro-flow simulation is carried out in FLUENT software,and then the porosity,permeability and seepage of the pore network model are predicted.In the aspect of image segmentation: on the basis of the traditional two-dimensional OTSU algorithm,based on the mean variance and neighborhood information,the algorithm is improved to extract the pore part to calculate the porosity.Compared with the algorithm before the improvement,the value is closer to the real core porosity.In the aspect of core modeling: Firstly,digital core is established based on the CT tomography sequence image after image processing,and then the core pore space surface model is constructed using MC algorithm based on digital core,and the surface model is repaired and optimized.The constraint condition for the formation of a pore network model is the pore space surface model.The maximum sphere technique is employed to divide the pore and throat,thus completing the core pore network model.The pore structure parameters of core were determined by using the real core mercury injection experiment data,and the pore network parameters were compared and analyzed.The two parameters have a high consistency,indicating the accuracy of the established model.FLUENT,a fluid dynamics analysis software,was employed to simulate the single-phase and two-phase flow of the pore network model in oil-water,and the indoor phase permeability experiment data was compared.The two have a high consistency,indicating that the simulation results have a certain reference value.Constructing a visual system software platform: Desinger’s Python+Pyqt5+Qt is employed to construct the system framework,while designing the data structure of the software platform.Realizing the human-computer interaction capability of the software platform,constructing the shared data interface of SOLIDWORKS software,and programming various algorithms-these are the tasks that must be accomplished.The model’s visual display is realized by combining VTK technology.