94 / 2022-01-29 20:09:16

基于数字岩心技术的沉积、压实、胶结和溶蚀作用模拟

Digital rock technique,Diagenesis,Discrete element method,Cementation,Dissolution,Pore system

Sedimentary rocks form after the sediments experience a series of diagenesis events, such as deposition, cementation, and dissolution. It is of great difficulty to quantitively simulate the diagenesis events using computationally numerical techniques since these events involve chemical and physical reactions between the fluids and minerals. In this paper, some novel methods based on the digital rock technique are presented to address the issues. The discrete element method is used to simulate the deposition and compaction of mineral particles, and the dilation operation and quartet structure generate set algorithms are utilized to simulate the cementation and dissolution. The new digital rocks are generated after the original rock undergoes a diagenesis event. Besides, the effects of diagenesis events and diagenesis pathways on rock properties are comprehensively analyzed. The results show that cementation can decrease the porosity, fractal dimension, pore/throat radius, coordination number, correlation of pore space, permeability, and velocity values of the rocks and increase the tortuosity and formation factor of pore space. Comparing the cementation, the dissolution makes a reverse effect on rock properties. The diagenesis pathway also has an impact on the physical properties of digital rocks. In a word, the study will present a comprehensive workflow about the simulation of deposition, compaction, cementation, and dissolution and help us to better understand the variations of the flow and mechanical properties of rocks without conducting extensive experiments if rocks experience different diagenesis processes along different pathways.