Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures

In fractured reservoirs, fractures serve as both water channeling and oil flow channels. Because of the impact of bottom water coning, the water channeling phenomenon becomes more problematic in the middle and late stages of reservoir development. Furthermore, residual oil is limited to small-scale...

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Main Authors: Shuanghu Si, Yifei Liu, Yinghui Jiang, Chenwei Zou, Ning Yang, Dongfang Lv, Xizhuo Miao, Caili Dai
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Gels
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Online Access:https://www.mdpi.com/2310-2861/11/4/305
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author Shuanghu Si
Yifei Liu
Yinghui Jiang
Chenwei Zou
Ning Yang
Dongfang Lv
Xizhuo Miao
Caili Dai
author_facet Shuanghu Si
Yifei Liu
Yinghui Jiang
Chenwei Zou
Ning Yang
Dongfang Lv
Xizhuo Miao
Caili Dai
author_sort Shuanghu Si
collection DOAJ
description In fractured reservoirs, fractures serve as both water channeling and oil flow channels. Because of the impact of bottom water coning, the water channeling phenomenon becomes more problematic in the middle and late stages of reservoir development. Furthermore, residual oil is limited to small-scale fractures. In multi-scale fractures, the conventional pressure-bearing pattern of plugging agents is ambiguous. This results in low oil recovery, low sweep efficiency from water flooding, and low plugging agent application efficiency. Until now, the pressure-bearing patterns related to gel strength in multi-scale fractures have not been clear. In this paper, the gelation performances of temperature-resistant gel (TRG) samples with different elastic moduli were investigated. The elastic modulus of the TRG was normalized by the elastic modulus (G′) and viscosity modulus (G″). Subsequently, we carried out research on the bottom water pressure patterns of TRGs. This study revealed the pressure-bearing patterns of the TRGs under multi-scale fractures. A corresponding influence pattern chart was established, and the optimal surface function was fitted using the MATLAB nonlinear surface data fitting method. Finally, an application experiment for the characteristic chart was carried out. The plugging rate was evaluated based on the permeability reduction and pressure differential across the core samples before and after gel injection. Subsequently, a TRG with certain elastic moduli before and after plugging the core fracture node was selected from the chart. The elastic modulus of the TRG at the injection node prior to plugging was 14.29 Pa. The elastic modulus of the TRG at the injection node after plugging was 19.42 Pa. The experimental results showed that the TRG with an elastic modulus of 19.42 Pa effectively plugged the fractures and remained stable for over 90 days under a pressure differential of 53 KPa, resulting in a 58.7% improvement in oil recovery compared with water flooding. However, it was difficult for the TRG with an elastic modulus of 14.29 Pa to plug fractures efficiently, and it only enhanced the oil recovery by 15.2%. The primary aim of this work was to establish a quantitative and normalized evaluation method for temperature-resistant gels (TRGs) used in fractured reservoirs. By introducing a classification system based on the elastic modulus (G′) and correlating it with the fracture scale and plugging performance, this study bridges the gap between laboratory gel evaluations and field applications. The results provide practical design criteria and contribute to improving the efficiency and adaptability of gel plugging strategies under harsh reservoir conditions.
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spelling doaj-art-57ead5bf89c44d3aab55f953f7b877642025-08-20T02:17:59ZengMDPI AGGels2310-28612025-04-0111430510.3390/gels11040305Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale FracturesShuanghu Si0Yifei Liu1Yinghui Jiang2Chenwei Zou3Ning Yang4Dongfang Lv5Xizhuo Miao6Caili Dai7State Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaState Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaChina Petroleum and Natural Gas Co., Ltd. Yumen Oilfield Huanqing Branch, Qingyang 745700, ChinaTianjin Branch of CNOOC (China) Co., Ltd., Tianjin 300450, ChinaState Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaState Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaState Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaState Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, ChinaIn fractured reservoirs, fractures serve as both water channeling and oil flow channels. Because of the impact of bottom water coning, the water channeling phenomenon becomes more problematic in the middle and late stages of reservoir development. Furthermore, residual oil is limited to small-scale fractures. In multi-scale fractures, the conventional pressure-bearing pattern of plugging agents is ambiguous. This results in low oil recovery, low sweep efficiency from water flooding, and low plugging agent application efficiency. Until now, the pressure-bearing patterns related to gel strength in multi-scale fractures have not been clear. In this paper, the gelation performances of temperature-resistant gel (TRG) samples with different elastic moduli were investigated. The elastic modulus of the TRG was normalized by the elastic modulus (G′) and viscosity modulus (G″). Subsequently, we carried out research on the bottom water pressure patterns of TRGs. This study revealed the pressure-bearing patterns of the TRGs under multi-scale fractures. A corresponding influence pattern chart was established, and the optimal surface function was fitted using the MATLAB nonlinear surface data fitting method. Finally, an application experiment for the characteristic chart was carried out. The plugging rate was evaluated based on the permeability reduction and pressure differential across the core samples before and after gel injection. Subsequently, a TRG with certain elastic moduli before and after plugging the core fracture node was selected from the chart. The elastic modulus of the TRG at the injection node prior to plugging was 14.29 Pa. The elastic modulus of the TRG at the injection node after plugging was 19.42 Pa. The experimental results showed that the TRG with an elastic modulus of 19.42 Pa effectively plugged the fractures and remained stable for over 90 days under a pressure differential of 53 KPa, resulting in a 58.7% improvement in oil recovery compared with water flooding. However, it was difficult for the TRG with an elastic modulus of 14.29 Pa to plug fractures efficiently, and it only enhanced the oil recovery by 15.2%. The primary aim of this work was to establish a quantitative and normalized evaluation method for temperature-resistant gels (TRGs) used in fractured reservoirs. By introducing a classification system based on the elastic modulus (G′) and correlating it with the fracture scale and plugging performance, this study bridges the gap between laboratory gel evaluations and field applications. The results provide practical design criteria and contribute to improving the efficiency and adaptability of gel plugging strategies under harsh reservoir conditions.https://www.mdpi.com/2310-2861/11/4/305fractured reservoirTRGpressure-bearinginfluence chartapplication experiment
spellingShingle Shuanghu Si
Yifei Liu
Yinghui Jiang
Chenwei Zou
Ning Yang
Dongfang Lv
Xizhuo Miao
Caili Dai
Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
Gels
fractured reservoir
TRG
pressure-bearing
influence chart
application experiment
title Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
title_full Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
title_fullStr Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
title_full_unstemmed Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
title_short Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures
title_sort study on pressure bearing patterns of gel plugging agents in multi scale fractures
topic fractured reservoir
TRG
pressure-bearing
influence chart
application experiment
url https://www.mdpi.com/2310-2861/11/4/305
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