Experimental Investigation of the Novel Phenol−Formaldehyde Cross-Linking HPAM Gel System: Based on the Secondary Cross-Linking Method of Organic Cross-Linkers and Its Gelation Performance Study after Flowing through Porous Media

Abstract

The use of a polymer gel is an effective method for water shutoff in mature oilfield development. As for fractured reservoirs, in order to mitigate the filtration of gelant (fluid solution of cross-linker and polymer that exists before gelation) to matrix and increase the enduring erosion ability of mature gel, chromium(III) acetate, and phenol-formaldehyde cross-linking, the HPAM gel system of a secondary cross-linking method is used more often. Chromium(III) salt is often used as the first cross-linker. However, the crosslinking mechanism is achieved by an ion bond, which is less stable than a covalent bond when used as an organic cross-linker. Resorcinol and phenol-formaldehyde used as the first and secondary cross-linker, respectively, are discussed in this paper. Results showed that resorcinol can quickly cross-link with HPAM at room temperature. Gelant formulated with a combination of 0.3 wt % HPAM added to 10-30 mg/L resorcinol can increase its viscosity from 10.2 to 150 mPa 3 s within 2 h. SEM results show that the microstructure of the first cross-linking gel appears in typical dendritic shape, with branched chains diffused in arbitrary directions. The high shearing tolerant ability of the first cross-linking gel can be achieved by these branched chains. However, a tight 3-D network structure is formed in the microstructure of the secondary cross-linking gel. This is the benefit of the stability of the skeleton structure of gel enhancing. The main factors, including temperature and total dissolved solids (TDS), to affect the gelation performance of this secondary cross-linking gel are also discussed. Results show that gelation time decreased and gel strength increased with increasing temperature and TDS. Especially for TDS, the adverse law of the gelation performance with PEI/PAtBA or PEI/HPAM gel systems is shown. The gelation performance of a resorcinol/phenol-formaldehyde/HPAM gel system of a first cross-linking state after flowing through porous media is studied. Atomic force microscopy (AFM) scanning results show that in comparison to the original gel, the structure of the weak cross-linking (code B) gels has a certain degree of damage after flowing through porous media. However, the final gel strength of both gels do not show an apparent difference. This demonstrated that the first cross-linking achieved by resorcinol can guarantee the effectiveness of secondary cross-linking. This study suggests that a resorcinol/phenolformaldehyde/HPAM secondary cross-linking gel system can be used for water shutoff in fractured reservoirs.

Investigation of Injection Strategy of Branched-Preformed Particle Gel/Polymer/Surfactant for Enhanced Oil Recovery after Polymer Flooding in Heterogeneous Reservoirs

“…Thus, with the popularization of polymer flooding technology, how to further enhance oil recovery after polymer flooding attracts more and more concerns. Therefore, many technologies including polymer-surfactant flooding [10,11], alkaline-surfactant-polymer flooding [12][13][14], foam flooding [15][16][17][18], and gel treatment [19][20][21][22] have been developed to further enhance oil recovery by improving the sweep efficiency and oil displacement efficiency. Gel treatment has been recognized as an effective technology to enhance oil recovery after polymer flooding.…”

Study on a Novel Gelled Foam for Conformance Control in High Temperature and High Salinity Reservoirs

“…Nevertheless, most traditional profile control agents do not meet the requirements of field applications. For example, polymer flooding is only suitable for low-temperature conditions of no higher than 90 • C since higher temperatures cause heat degradation in polymers [16]. Combined flooding, including alkaline-surfactant-polymer (ASP) flooding and surfactant-polymer (SP) flooding, is very difficult to apply under harsh conditions.…”

Influence of strong preformed particle gels on low permeable formations in mature reservoirs

“…Particle gels contain PPGs, microgels, swelling micrometersized polymers (Bright Water R ), and a pH-sensitive crosslinked polymer (Coste et al 2000;Chauveteau et al 2000Chauveteau et al , 2001Al-Anaza and Sharma 2002;Pritchett et al 2003;Frampton et al 2004;Huh et al 2005;Rousseau et al 2005;Bai et al 2007aBai et al , b, 2008Zaitoun et al 2007;Roussennac and Tosschi 2010;Zhang et al 2010;Jia et al 2011;Juntail et al 2011a, b). Table 1 displays different types of particle gels used in the oil industry, related studies and the researchers who developed these gels, particle size, and applications.…”