Recently, Zhang Kai's team has made new progress in the field of intelligent video analysis for well site workover operations. The related research results have been published in Geoenergy Science and Engineering, with the paper titled "A Dual-Porosity Flow-Net Model for Simulating Water-Flooding in Low-Permeability Fractured Reservoirs."
Innovative：
Existing physics-based and data-driven models are mostly suitable for conventional water-flooding reservoirs, but they do not adequately describe the phenomenon of rapid water breakthrough along fractures in low-permeability fractured reservoirs. To address this issue, we combine the flow network model with the dual-porosity model and propose a new physics-based data-driven surrogate model, the Dual-Porosity Flow Network Model (Flow-Net-DP). This model discretizes the reservoir into a network of pipelines consisting of fracture and matrix grids. The grid parameters are solved using the Newton iteration method. Finally, the Ensemble Smoother with Multiple Data Assimilation (ES-MDA) algorithm is employed for history matching, and the Differential Evolution (DE) algorithm is used for production optimization. The results indicate that this method demonstrates excellent performance in low-permeability fractured reservoirs.
Abstract：
The development potential of low-permeability fractured reservoirs is immense, and numerical simulation stands out as the most effective tool for their detailed geological characterization and the formulation of efficient development strategies. However, the complex pore structures and fluid flow patterns present a challenge in establishing accurate full-scale simulation models. Therefore, an alternative approach involves devising a simplified model that ensures computational accuracy while rapidly fitting production history. Numerous scholars have researched proxy models, but these models often exhibit better adaptability only in conventional water-drive sandstone reservoirs and perform poorly in fractured reservoirs. This paper aims to introduce a dual-porosity flow network model, referred to as the Flow-Net-DP model, wherein two channels represent the connections between wells in the reservoir. One channel signifies the fracture system, and the other represents the matrix system. Each channel is discretized into one-dimensional grids, with parameters such as permeability, porosity, grid volume, pressure, and water saturation defined within each grid, enabling efficient numerical simulation and history matching for waterflooded low-permeability fractured reservoirs. The model can comprehensively consider the non-Darcy equation for the matrix system, the stress-sensitive effects within the fracture system, and the fluid exchange between these two systems. An efficient history-matching procedure based on the Flow-Net-DP model of the fractured reservoir is used to determine the parameters of connection grids and then allows for precise numerical simulations. A comparative analysis is conducted by contrasting the Flow-Net-DP model with the Flow-Net model using two-dimensional reservoir models. The results indicate that the Flow-Net-DP model is capable of describing the rapid breakthrough of injected water along fracture channels in fractured reservoirs. Finally, the proposed method is applied to an actual low-permeability fractured reservoir, and the results demonstrate a favorable agreement between the simulation outcomes and the actual production history.
Geoenergy Science and Engineering covers the fields of exploration, production, and flow of oil and gas, including: reservoir engineering; reservoir simulation; rock mechanics; rock physics; pore-scale phenomena; logging, testing, and evaluation; mathematical modeling; enhanced oil and gas recovery; fluid mechanics; multiphase flow in porous media; production engineering; formation evaluation; exploration methods; geological structures/underground CO2 sequestration, etc. The latest impact factor of this journal is 4.4, with a three-year average impact factor (IF) of 4.5. It is ranked in the Q1 quartile by JCR and is categorized in the second quartile in the field of engineering technology by the Chinese Academy of Sciences.
Article link：
https://doi.org/10.1016/j.geoen.2024.213069
Cite：
Xia Yan, Guo-Yu Qin, Li-Ming Zhang*, Kai Zhang, Yong-Fei Yang, Jun Yao, Jia-Lin Wang, Qin-Yang Dai, Da-Wei Wu. A Dual-Porosity Flow-Net Model for Simulating Water-Flooding in Low-Permeability Fractured Reservoirs[J]. Geoenergy Science and Engineering, 2024, 240: 213069.
