Open Access

ARTICLE

Numerical Simulation Method of Meshless Reservoir Considering Time-Varying Connectivity Parameters

Yuyang Liu^1,2,*, Wensheng Zhou^1,2, Zhijie Wei^1,2, Engao Tang^1,2, Chenyang Shi³, Qirui Zhang^4,*, Zifeng Chen⁴

1 State Key Laboratory of Offshore Oil and Gas Exploitation, Beijing, 100028, China
2 Research & Development Center of Offshore Oil Exploitation, CNOOC Research Institute Ltd., Beijing, 100020, China
3 Bohai Oilfield Research Institute, Tianjin of CNOOC Ltd., Tianjin, 300459, China
4 School of Petroleum Engineering, Yangtze University, Wuhan, 430100, China

* Corresponding Authors: Yuyang Liu. Email: ; Qirui Zhang. Email:

(This article belongs to the Special Issue: Integrated Geology-Engineering Simulation and Optimizationfor Unconventional Oil and Gas Reservoirs)

Energy Engineering 2025, 122(10), 4245-4260. https://doi.org/10.32604/ee.2025.066167

Received 31 March 2025; Accepted 17 June 2025; Issue published 30 September 2025

Abstract

After a long period of water flooding development, the oilfield has entered the middle and high water cut stage. The physical properties of reservoirs are changed by water erosion, which directly impacts reservoir development. Conventional numerical reservoir simulation methodologies typically employ static assumptions for model construction, presuming invariant reservoir geological parameters throughout the development process while neglecting the reservoir’s temporal evolution characteristics. Although such simplifications reduce computational complexity, they introduce substantial descriptive inaccuracies. Therefore, this paper proposes a meshless numerical simulation method for reservoirs that considers time-varying characteristics. This method avoids the meshing in traditional numerical simulation methods. From the fluid flow perspective, the reservoir’s computational domain is discretized into a series of connection units. An influence domain with a certain radius centered on the nodes is selected, and one-dimensional connection units are established between the nodes to achieve the characterization of the flow topology structure of the reservoir. In order to reflect the dynamic evolution of the reservoir’s physical properties during the water injection development process, the time-varying characteristics are incorporated into the formula of the seepage characteristic parameters in the meshless calculation. The change relationship of the permeability under different surface fluxes is considered to update the calculated connection conductivity in real time. By combining with the seepage control equation for solution, a time-varying meshless numerical simulation method is formed. The results show that compared with the numerical simulation method of the connection element method (CEM) that only considers static parameters, this method has higher simulation accuracy and can better simulate the real migration and distribution of oil and water in the reservoir. This method improves the accuracy of reservoir numerical simulation and the development effect of oilfields, providing a scientific basis for optimizing the water injection strategy, adjusting the production plan, and extending the effective production cycle of the oilfield.

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Keywords

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