Biodegradable Preformed Particle Gel (PPG) Made of Natural Chitosan Material for Water Shut-Off Application

Abstract

Oil and gas extraction frequently produces substantial volumes of produced water, leading to several mechanical and environmental issues. Several methods have been applied over decades, including chemical processes such as in-situ crosslinked polymer gel and preformed particle gel, which are the most effective nowadays. This study developed a green and biodegradable PPG made of PAM and chitosan as a blocking agent for water shutoff, which will contribute to combating the toxicity of several commercially used PPGs. The applicability of chitosan to act as a crosslinker has been confirmed by FTIR spectroscopy and observed by scanning electron microscopy. Extensive swelling capacity measurements and rheological experiments were performed to examine the optimal formulation of PAM/Cs based on several PAM and chitosan concentrations and the effects of typical reservoir conditions, such as salinity, temperature, and pH. The optimum concentrations of PAM with 0.5 wt% chitosan were between 5–9 wt%, while the optimum chitosan amount with 6.5 wt% PAM was in the 0.25–0.5 wt% range, as these concentrations can produce PPGs with high swellability and sufficient strength. The swelling capacity of PAM/Cs is lower in high saline water (HSW) with a TDS of 67.2976 g/L compared with fresh water, which is related to the osmotic pressure gradient between the swelling medium and the PPG. The swelling capacity in freshwater was up to 80.37 g/g, while it is 18.73 g/g in HSW. The storage moduli were higher in HSW than freshwater, with ranges of 1695–5000 Pa and 2053–5989 Pa, respectively. The storage modulus of PAM/Cs samples was higher in a neutral medium (pH = 6), where the fluctuation behavior in different pH conditions is related to electrostatic repulsions and hydrogen bond formation. The increase in swelling capacity caused by the progressive increment in temperature is associated with the amide group’s hydrolysis to carboxylate groups. The sizes of the swollen particles are controllable since they are designed to be 0.63–1.62 mm in DIW and 0.86–1.00 mm in HSW. PAM/Cs showed promising swelling and rheological characteristics while demonstrating long-term thermal and hydrolytic stability in high-temperature and high-salinity conditions.

Development of Inorganically Cross-Linked Sulfonated Polyacrylamide Preformed Particle Gels for Conformance Control: Impact of Anionic Groups

“…Hence, it leads to a decrease in hydrophilicity and swelling capacity. Consistent findings in multiple studies further verify the correlation between cross-linker quantity and swelling capacity and strength. , Although concentrations of 0.2 and 0.4 wt % yield gels with exceptionally high swelling ratios in deionized water, they are relatively weak. Therefore, the optimal cross-linker concentration for achieving robust gels with 4 wt % SPAM is 0.6 wt %.…”

“…This is because a looser network allows for higher water absorption and retention, as observed in the SPAM/AlAc. Many studies have illustrated a consistent trend of a reverse relationship between the PPG strength and swelling capacity. , …”

A Review of Recent Developments in Nanomaterial Agents for Water Shutoff in Hydrocarbon Wells

“…However, the application of these gels is limited to high permeable formation (not less than 500 mf) and fractures due to particle size constraints . Preformed gel types include partially preformed gels, , preformed particle gels of millimeter to micro size (PPG), ,, microgels, − pH-sensitive cross-linked polymers, − and Bright Water. , The main differences include the swelling capabilities, particle size, and the preferred reservoir conditions to be used . In addition to that, different types of mechanisms were used to combat water production such as partial plugging, , relative permeability modification, large pores plugging, mobilizing capillary-trapped oil and monolayer or multilayer adsorption. ,, Figure displays SEM images of swelling and aggregation of PPG and microgel in the porous media which will reflect on the achieved plugging efficiency.…”

Development of Agar-Based Preformed Particle Gel for Water Control in High-Salinity Reservoirs

“…34 Besides the environmental concerns, sustained economic concerns due to the continuous diminishing of nonrenewable resources were the primary trigger for developing nontoxic, biodegradable, and ecofriendly materials. 32,35,36 Polysaccharides are biopolymers made of monosaccharide units connected by glycosidic linkages, naturally produced by various living organisms. They possess numerous advantages: abundance, low cost, renewable, nontoxicity, biocompatibility, and biodegradability.…”

“…Furthermore, synthetic polymers have been utilized and released into the environment as nonbiodegradable waste over the years, where their accumulation could be hazardous as they damage or change the natural ecosystem . Besides the environmental concerns, sustained economic concerns due to the continuous diminishing of nonrenewable resources were the primary trigger for developing nontoxic, biodegradable, and eco-friendly materials. ,, …”