ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Georeservoirs
Volume 13 - 2025 | doi: 10.3389/feart.2025.1591312
Criteria of Wells and Layers Selection for Fracturing-Flooding Practice in Offshore Low-permeability Reservoirs Based on Numerical Simulation
Provisionally accepted
- 1Zhanjiang Branch of CNOOC Ltd., Zhanjiang, China
- 2China Oilfield Services Ltd, Tianjin, China
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The success in the pilot test of offshore fracture-flooding provides a new technical idea for the development of low-permeability and under-injection oilfields. However, the lack of criteria for wells and layer selection has hindered the further implementation of fracture-flooding technologies. The establishment of such criteria requires a deep understanding of the production enhancement mechanisms during the fracture-flooding practice.Currently, there still lack a numerical simulation model for fracture-flooding that combines the mechanism of energy replenishment, porosity and permeability increase, crack initiation, oil displacement using surfactant and imbibition. Further more, the influence of individual mechanisms, i.e. how each mechanism contributes to the overall production enhancement, are not quantified. To fill the current knowledge gap in the mechanisms behind fracture-flooding practices, we have conducted experimental studies, established a numerical simulation method for fracture-flooding production enhancement mechanisms, and quantitatively characterized the effect of crack initiation, surfactant and imbibition during wells shut-in. Further studies on establishing the layer selection criteria for fracture-flooding were carried out with key indexes identified and ranked based on the quantification result of their influence on production enhancement. Results show that the oil-bearing condition has the first-order control on production enhancement compared to the physical properties of the reservoir, i.e., it is necessary to ensure the existence of a certain amount of residual reserves in the formation first. The established criteria have been tested in the field practice of fracture-flooding which shows the initial daily oil increase of 50 m 3 •d -1 , and the production capacity of the target layer was increased from 1.2 m 3 •(d•MPa) -1 to 9.2 m 3 •(d•MPa) -1 , and the cumulative oil increase reached 101,000 mcf in half a year. The field results show that the production enhancement effect has met the requirements of the fracture-flooding design. The field practice has proved the feasibility of using our numerical simulation method for the design of fracture-flooding and well/layer selection in the development of offshore lowpermeability reservoirs.
Keywords: offshore reservoir, low-permeability reservoir, fracture-flooding Practice, numerical simulation, Well and layer selection
Received: 11 Mar 2025; Accepted: 14 Apr 2025.
Copyright: © 2025 Tang, Wei, Ma, Deng, Zhang, Wang, Xing and Qiao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Runwei Qiao, China Oilfield Services Ltd, Tianjin, China
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