Development and evaluation of organic/inorganic combined gel for conformance control in high temperature and high salinity reservoirs

Abstract

Polymer gels have been successfully applied to control undesired water production for many years, however, due to poor long-term thermal stability and salt tolerance, conventional polymer gels present some limitations for application in high temperature and high salinity reservoirs. In this paper, an organic/inorganic combined gel composed of polymer with low degree of hydrolysis, phenol formaldehyde resin and inorganic silicate was proposed and developed. The effects of concentration, temperature on gelation time were studied. Long-term thermal stability, salt tolerance and permeability reduction ability were investigated. Results showed that based on proper gelation time and economical cost, the formulation of the organic/inorganic combined gel was optimized. The gelation time decreased from 54.0 to 15.5 h with increasing temperature from 100 to 130°C. After aging for 60 days in simulated formation brine with high total dissolved solids (TDS: 20 % NaCl ? 2.5 % CaCl 2 ) at 130°C, compared with polymer gel, the organic/inorganic combined gel had better long-term thermal stability and salt tolerance. Sandpack flow experimental results showed that for the organic/inorganic combined gel composed of 0.3 wt% polymer, 4.0 wt% resin and 3.0 wt% inorganic silicate, after aging for 60 days at 130°C, the combined gel showed approximately 85 % permeability reduction. Therefore, these results indicate that the combined gel studied here can be a good candidate for controlling water production in high temperature and high salinity reservoirs.

Swelling performance of sodium polyacrylate and poly(acrylamide-co-acrylic acid) potassium salt

“…Temperature is an important factor affecting the absorbency capacity of SPHs [25,39] and in this study different swelling behaviours were observed for the two superabsorbent materials tested. After 2-h of free swelling, the absorbency of the poly (acrylamide-co-acrylic acid) potassium salt decreased with increasing temperature with the peak absorbency occurring at 25 °C whereas and the lowest at 100 °C ( Fig.…”

In situ organically cross‐linked polymer gel for high‐temperature reservoir conformance control: A review

“…The gelation time was predicted to decrease, meanwhile the gel strength to increase with temperature . During the gelation process, the rate of cross‐linking between polymer and cross‐linker increases with increasing temperature . Higher temperature contributes to molecular motion to be accelerated.…”

“…Hence, CFA also has a potential to be a retarder for PAM/PEI gel system. The effect of inorganic silicate concentration on gelation time was studied by preparing different gelant solutions containing polymer, phenolic resin, and the inorganic silicate by He et al From the experiment, when inorganic silicate concentration increased from 1.0 to 8.0 wt%, the gelation time decreased from 19 to 4 hours. It can be understood that silicate itself can form another 3‐dimensional network structure, along with the formation of gel network by polymer.…”

“…95 During the gelation process, the rate of cross-linking between polymer and cross-linker increases with increasing temperature. 41,88 Higher temperature contributes to molecular motion to be accelerated. This phenomenon refers to the high mobility of gel molecules when heating which induces the gelation process to be faster.…”

The potential of using micro-sized crosslinked polymer gel to remediate water leakage in cement sheaths

“…It forms at the surface and then is dried and crushed into small particles to be injected into the reservoir. No gelation occurs in the reservoir (Imqam et al 2015a, b), though the gelation can be controlled by temperature and salinity (He et al 2015;Zheng et al 2017;Fuseni et al 2018). Yet, few laboratory studies investigate its ability in cement zonal isolation.…”