Gelation Behavior Study of a Resorcinol–Hexamethyleneteramine Crosslinked Polymer Gel for Water Shut-Off Treatment in Low Temperature and High Salinity Reservoirs

Abstract

Mature oilfields usually encounter the problem of high watercut. It is practical to use chemical methods for water-shutoff in production wells, however conventional water-shutoff agents have problems of long gelation time, low gel strength, and poor stability under low temperature and high salinity conditions. In this work a novel polymer gel for low temperature and high salinity reservoirs was developed. This water-shutoff agent had controllable gelation time, adjustable gel strength and good stability performance. The crosslinking process of this polymer gel was studied by rheological experiments. The process could be divided into an induction period, a fast crosslinking period, and a stable period. Its gelation behaviors were investigated in detail. According to the Gel Strength Code (GSC) and vacuum breakthrough method, the gel strength was displayed in contour maps. The composition of the polymer gel was optimized to 0.25~0.3% YG100 + 0.6~0.9% resorcinol + 0.2~0.4% hexamethylenetetramine (HMTA) + 0.08~0.27% conditioner (oxalic acid). With the concentration increase of the polymer gel and temperature, the decrease of pH, the induction period became shorter and the crosslinking was more efficient, resulting in better stability performance. Various factors of the gelation behavior which have an impact on the crosslinking reaction process were examined. The relationships between each impact factor and the initial crosslinking time were described with mathematical equations.

Overview of Water Shutoff Operations in Oil and Gas Wells; Chemical and Mechanical Solutions

“…The success of chemical injection operations depends on the knowledge level of the reservoir and its characterizations, chemical properties, and accurate placement of the injected chemicals [3,18]. For example, the effectiveness of water shutoff agents depends highly on the properties of the reservoir and has to be compatible with the reservoir temperature and water salinity in order to achieve an effective water shutoff [19]. In this section, common chemical solutions are discussed in detail, along with examples of the execution of the operations.…”

Study on the stability and green application exploration of waste drilling fluid

“…With the formation of covalent bonds between amide groups of the stabilizer and the cross‐linker A, the gel can withstand high temperatures. Furthermore, the introduction of benzene rings could increase the temperature resistance of gel systems . Cross‐linker B has low temperature‐resistant, due to the ionic bonding between the negatively charged carboxylate groups and trivalent aluminum ion.…”

“…Furthermore, the introduction of benzene rings could increase the temperature resistance of gel systems. 29,30 Cross-linker B has low temperature-resistant, due to the ionic bonding between the negatively charged carboxylate groups and trivalent aluminum ion. The viscosity of the gel system is good enough to meet the needs of high temperature.…”

The Thermal Gelation Behavior and Performance Evaluation of High Molecular Weight Nonionic Polyacrylamide and Polyethyleneimine Mixtures for Indepth Water Control in Mature Oilfields

“…The polyacrylamide contains a large number of amide groups (-CONH2) and carboxyl groups (-COO -) in its molecular chain after hydrolysis. It could crosslink with different types of crosslinkers, such as Cr 3+ [6,7], Al 3+ [8], Zr 4+ [9] or phenolic resin [10][11] et al. However, multivalent metal ions and phenolic resin are toxic.…”