Supramolecular polymer-based gel fracturing fluid with a double network applied in ultra-deep hydraulic fracturing  

作　　者：Yong-Ping Huang Yong Hu Chang-Long Liu Yi-Ning Wu Chen-Wei Zou Li-Yuan Zhang Ming-Wei Zhao Cai-Li Dai 

机构地区：[1]School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,266580,Shandong,PR China [2]Shandong Key Laboratory of Oilfield Chemistry,China University of Petroleum(East China)Qingdao 266580,Shandong,PR China [3]SINOPEC Petroleum Exploration and Production Research Institute,Beijing,102206,PR China [4]CNOOC China Co Ltd,Tianjin Branch,Tianjin,300459,PR China

出　　处：《Petroleum Science》2024年第3期1875-1888,共14页石油科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.52120105007 and 52374062);the Innovation Fund Project for Graduate Students of China University of Petroleum(East China)supported by“the Fundamental Research Funds for the Central Universities”(23CX04047A);。

摘　　要：A gel based on polyacrylamide,exhibiting delayed crosslinking characteristics,emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong wellbores.High viscosity/viscoelasticity of the fracturing fluid was required to maintain excellent proppant suspension properties before gelling.Taking into account both the cost and the potential damage to reservoirs,polymers with lower concentrations and molecular weights are generally preferred.In this work,the supramolecular action was integrated into the polymer,resulting in significant increases in the viscosity and viscoelasticity of the synthesized supramolecular polymer system.The double network gel,which is formed by the combination of the supramolecular polymer system and a small quantity of Zr-crosslinker,effectively resists temperature while minimizing permeability damage to the reservoir.The results indicate that the supramolecular polymer system with a molecular weight of(268—380)×10^(4)g/mol can achieve the same viscosity and viscoelasticity at 0.4 wt%due to the supramolecular interaction between polymers,compared to the 0.6 wt%traditional polymer(hydrolyzed polyacrylamide,molecular weight of 1078×10^(4)g/mol).The supramolecular polymer system possessed excellent proppant suspension properties with a 0.55 cm/min sedimentation rate at 0.4 wt%,whereas the0.6 wt%traditional polymer had a rate of 0.57 cm/min.In comparison to the traditional gel with a Zrcrosslinker concentration of 0.6 wt%and an elastic modulus of 7.77 Pa,the double network gel with a higher elastic modulus(9.00 Pa)could be formed only at 0.1 wt%Zr-crosslinker,which greatly reduced the amount of residue of the fluid after gel-breaking.The viscosity of the double network gel was66 m Pa s after 2 h shearing,whereas the traditional gel only reached 27 m Pa s.

关 键 词：Ultra-deep reservoir Gel fracturing fluid Double network Supramolecular polymer system Proppant suspension property 

分 类 号：TE357.12[石油与天然气工程—油气田开发工程]