Mechanism Study of the Cross-Linking Reaction of Hydrolyzed Polyacrylamide/Ac₃Cr in Formation Water

Abstract

The mechanism of the cross-linking reaction between hydrolyzed polyacrylamide (HPAM) and chromium acetate in formation water was systematically studied by viscometry, ultraviolet-visual absorption spectrometry, and core flow experiments. The results show that the process and outcome of the cross-linking reaction between HPAM and chromium acetate is significantly affected by salinity. In formation water, chromium acetate cannot cross-link HPAM when the salinity is too low. With an increase of salinity, the cross-linking reaction occurs, and the degree of the reaction increases to a balance point. When the cross-linking reaction occurs, two different types of the reaction appear under different salinity. The intramolecular crosslinking reaction is the first to happen, whether under high salinity or under low salinity. In this stage, the cross-linking reaction is a first-order reaction and plays a greater role in the whole process of the reaction due to its higher reaction rate and higher reaction degree. Next, the intramolecular cross-linking continues to occur if the formation water is in the low salinity range, but the intermolecular cross-linking reaction occurs if the formation water is in the high salinity range. In this stage, the cross-linking reaction is a multistage reaction. Meanwhile, the experiments quantify a matching relationship between cations in the formation water and the profile control and oil displacement agent. The experimental results in this paper can provide theoretical guidance for the practical application of profile control and oil displacement using HPAM/Ac 3 Cr.

A Novel Study on the Gel Phase Formed in a Catanionic Surfactant System

“…In general, gels can be easily formed by polymers in solution. The most popular polymer in the world is hydrolyzed polyacrylamide (HPAM), due to its low cost and good performance [9][10][11][12][13][14][15][16][17]. When HPAM and crosslinker are mixed in aqueous solution, gels can be easily constructed, which can be ascribed to the construction of a three-dimensional network [10].…”

“…ions [11]. This kind of polymer gel is widely used in oilfield applications, such as profile control, water shutoff and fracturing processes [10][11][12]. Our group has done a large amount of research concerning the construction of such gels and their use in oilfield applications in the recent years [13][14][15][16][17].…”

Self‐healing behaviors of sulfobetaine polyacrylamide/chromium gel decided by viscosity and chemical compositions

“…Second, the carboxyl amide groups could coordinate with Cr 3+ since they can hydrolyze into carboxyl groups. The whole process of the self‐healing reaction is decided by the intramolecular crosslinking between Cr 3+ and PAM . In addition, the positive and negative charges of the amphoteric ions in the hydrophilic groups have electrostatic attraction, since the quaternary ammonium salt groups are positively charged and the sulfonic acid groups are negatively charged .…”

“…The whole process of the self-healing reaction is decided by the intramolecular crosslinking between Cr 3+ and PAM. 25 In addition, the positive and negative charges of the amphoteric ions in the hydrophilic groups have electrostatic attraction, since the quaternary ammonium salt groups are positively charged and the sulfonic acid groups are negatively charged. 26 At this stage, the selfhealing reaction is a multistage reaction, in which the electrostatic interaction and hydrogen bonding are going to coexist.…”

Influence of salinity on the properties of the different HPAM/Al3+systems

“…The HPAM/Al 3+ system 1 consists of HPAM and aluminum citrate 1, the HPAM/Al 3+ system 2 consists of HPAM and aluminum citrate 2, and the HPAM/Al 3+ system 3 consists of HPAM and aluminum citrate 3. The details parameters of the three HPAM/Al 3+ systems are shown in Table 1 [40][41][42]. All solutions are prepared by using the simulated formation water samples.…”