Quantitative fracture density prediction based on energy composition and
strain energy theory
SHI Guangyao1，2，LI Li1
(1. School of Geosciences，China University of Petroleum(East China)，Qingdao，Shandong 266580，China；2. Henan Geological Investigation and Designing Institute Co.，Ltd.，Zhengzhou，Henan 450014，China)
Abstract：The quantitative prediction of fractures is of great significance to the exploration and exploitation of fractured reservoirs. While the accuracy of fracture prediction model is very important in prediction. Based on the theory of strain energy and the law of thermodynamics，a prediction model for calculating the volume density of new fracture is built. Firstly，the plastic strain and the condition of triaxial stress in origin of new fractures，which had been neglected by predecessors in fracture prediction，are fully considered. Secondly, the total energy，elastic strain energy and plastic strain energy absorbed by the rock to generate the new fracture are calculated through the formula and derivation of elastic-plastic theory. Finally，the prediction model of the volume density of new fracture is caculated. This new volume fracture prediction model theoretically revealed the relationship between the origin and development of fractures and triaxial principal stress and lithology. Using ANSYS finite element software，the stress field of Chun 41 block in Dongying depression during the period of Eocene Es3–2 deposition is simulated. Using the APDL programming language of ANSYS software，the stress value of each node is obtained. Then，the prediction model of fracture density is added into ANSYS software to predict fracture density. The prediction results show that the northern arc of Chun Bei fault in the study area is a fracture zone for oil and gas exploition. Compared with the fracture prediction of traditional structural stress field simulation，this new model based on the theory of strain energy and the law of thermodynamics is more accurate with a higher accuracy than previous model in fracture prediction. Therefore，it is of great significance to the exploition of fractured oil and gas pool.
时光耀1，2，李 理1. 基于能量组成及应变能理论的裂缝密度定量预测[J]. 岩石力学与工程学报, 2021, 40(S1): 2826-2833.
SHI Guangyao1，2，LI Li1. Quantitative fracture density prediction based on energy composition and
strain energy theory. , 2021, 40(S1): 2826-2833.
2021, Vol. 40 
