Preparation Method and Performance Evaluation of a Gel Based on AM/AMPS Copolymer

Abstract

Polymer gels have been widely used in high water cut oilfields for profile control and water plugging. It is urgent to develop a gel suitable for the Tahe Oilfield (Temperature: 130 °C, salinity: 2.2 × 105 mg/L) in China. A stable gel was prepared by using an acrylamide (AM)/2-acrylamide-2-methyl propanesulfonic acid (AMPS) copolymer crosslinked with urotropin (HMTA), hydroquinone (HQ), thiourea and Nano-SiO2. This paper covers a step-by-step process for designing gels based on experience with preparing gels. A wide range of combinations between polymers and crosslinking agents with and without stabilizers were investigated, and the results indicated that there is an optimal value of AMPS content of AM/AMPS copolymers in the preparation of gels. Increasing the mass fraction of copolymer and using stabilizer enhanced the performance of gel, but an excessive amount of crosslinking agent was not conducive to the stability of gel. The work optimized the formula of plugging agent suitable for the high temperature and high salt (HTHS) condition in the Tahe Oilfield. The gelling solution had a long gelation time of 20 h. The gel had high strength (Sydansk’s gel-strength code of “G”) with storage modulus of 12.9 Pa and could be stable for half a year at 130 °C and 2.2 × 105 mg/L of salinity. The plate model that could be heated and pressurized was used to simulate the oil flooding and profile modification under the condition of the Tahe Oilfield for the first time. The experiment results showed that the oil recovery could be increased by 13.22% by subsequent water flooding under heterogeneous formation condition. Therefore, it was fully confirmed that the plugging performance of AM/AMPS phenolic gel prepared in the work was excellent. The information provided in the study could be used as a reference for the design and evaluation of polymer gels in other HTHS reservoirs.

Study on Water-Soluble Phenolic Resin Gels for High-Temperature and High-Salinity Oil Reservoir

“…In addition, the storage modulus of the gel was evaluated using a rheometer at a temperature of 25 °C. The setting method of the instrument can be referred to our previous article [ 34 ].…”

“…After sealing the sample, the gelation time and gel strength were observed at ambient temperature. In addition, the storage modulus of the gel was evaluated using a rheometer at a temperature of 25 • C. The setting method of the instrument can be referred to our previous article [34].…”

Progress and Prospects of In Situ Polymer Gels for Sealing Operation in Wellbore and Near-Well Zone

“…We list a variety of temperature-resistant copolymer gels, as shown in Table , and it can be seen that the most commonly used temperature-resistant monomer is AMPS. Using cyclic hexamethylenetetramine and phenolic compounds to cross-link AM/AMPS copolymers, the gels can be made to persist at 130 °C for 30–100 days, − the main mechanism being the cross-linking of the amide group of the copolymers (−CONH 2 ) with the hydroxyl group of the phenolic compounds (−CH 2 OH). It has been suggested that the AMPS/AM copolymer system has better thermal stability mainly due to the following reasons. , (1) AMPS has a long branched chain and sulfonic acid groups, which make AMPS more thermally stable than AM.…”

HPAM-biomass phenol-formaldehyde resin dispersion system: evaluation of stability

“…Polymer ooding is an important tool for oil eld development to further improve recovery, but it faces challenges in high saline reservoirs. 9,10 polymer ooding an enhanced oil recovery method that utilises high molecular weight polymers to increase the viscosity of injected uids, thus improving sweep e ciency and altered mobility ratio between oil and injected uid. 11,12 Although the effect is not ideal for the non-heterogeneity characteristics of highly mineralised reservoirs.…”