Comparison of an Emulsion- and Solution-Prepared Acrylamide/AMPS Copolymer for a Fluid Loss Agent in Drilling Fluid

Abstract

Acrylamide polymers were widely used as oilfield chemical treatment agents because of their wide viscosity range and versatile functions. However, with the increased formation complexity, their shortcomings such as poor solubility and low resistance to temperature, salt, and calcium were gradually exposed. In this paper, acrylamide (AM)/2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) copolymers were synthesized by aqueous solution polymerization and inverse emulsion polymerization, respectively. The aqueous polymer (W-AM/AMPS) and the inverse emulsion polymer (E-AM/AMPS) were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and particle size analysis. The rheological properties, filtration properties, and sodium ion (Na+) and calcium ion (Ca2+) resistance were investigated. The results showed that E-AM/AMPS not only had a dissolution speed 4 times faster than that of W-AM/AMPS but also had superior shear-thinning performance both before and after aging. The filtration property of the bentonite system containing 2 wt % E-AM/AMPS was also better than that of the bentonite system containing 2 wt % W-AM/AMPS. In addition, E-AM/AMPS also exhibited extremely high tolerance for Na+ and Ca2+. The huge difference between rheological and filtration properties of E-AM/AMPS and W-AM/AMPS in drilling fluid can be attributed to the differences in the polymer microstructure caused by the two polymerization methods. Both FTIR and 1H NMR results showed that more hydrogen bonds were formed between E-AM/AMPS molecular groups and molecular chains, which led to a cross-linked network structure of E-AM/AMPS which was observed by TEM. It was this cross-linked network structure that made E-AM/AMPS have a high viscosity and allowed it to be better adsorbed on bentonite particles, thus exhibiting excellent rheological and filtration behavior. In addition, E-AM/AMPS powder had a high specific surface area so that it can be dissolved in water faster, greatly reducing the time and difficulty of configuring drilling fluid.

Experimental Study on the Polymer/Graphene Oxide Composite as a Fluid Loss Agent for Water-Based Drilling Fluids

“…A higher YP/PV value is conducive to effective rock breaking at high shear rates and effective rock debris carrying capacity at low shear rates. 25 It can be seen from Table 2 that PAAN-G was more conducive to obtaining high YP/PV values than PAAN. In addition, PAAN-0.2G was better than PAAN-0.5G because PAAN-0.2G can still maintain a suitable YP/PV value at 180 °C, while PAAN-0.5G did not.…”

“…The suspension was stirred quickly for 20 min and then stirred at low speed and aged for 24 h at room temperature. 25 Then, different concentrations of PAAN, PAAN-0.2G, and PAAN-0.5G were added to the base slurry slowly and stirred at 6000 rpm for 20 min.…”

Grafted Starch Foam Stabilizer ESt‐g‐NAA for High‐Temperature Resistant CGA Drilling Fluid via Inverse Emulsion Polymerization

“…When the ESt-g-NAA concentration increases to 3%, the FL of drilling fluid within 180°C is 7-11.5 mL, which meets the API standard. As shown in Table 5, it is self-evident that EStg-NAA significantly improves the high-temperature fluid loss of Water-based drilling fluid containing 2% AM/AMPS copolymer [29] 11.2 (+38.3%) 22 (+107.5%) 0.37 0.73…”

“…Compared with aqueous radical polymerization (ARP), the IEP method has the following advantages: 1) Wang Zhonghua points out that the products synthesized through IEP have a stronger ability to increase viscosity, temperature, and high-valent metal ions resistance, which has been verified by Ma et al through comparing the temperature (150-200°C) and salt resistance (Na + /Ca 2+ ) of fluid loss agents obtained by ARP and IEP. [28,29] 2) The IEP polymerization can provide sufficient stability throughout the polymerization and distillation process to ensure high solid content and viscosity without the loss of product due to the clotting formation. As reported by Jose et al, highly concentrated inverse anionic polymeric emulsions were prepared (with a solids content of up to 63 wt%) through the IEP.…”

“…[32] As reported by Ma et al, the AM/AMPS polymer synthesized by IEP has a dissolution rate almost four times faster than that of the copolymer obtained by ARP. [29] The improvement of polymer solubility helps to reduce the time of slurry preparation and improve drilling efficiency. Therefore, despite the complexity of the synthesis processes and higher costs, the IEP has attracted more and more attention in the development of novel oil/gas field treatment agents, yet less investigated on the modified starch via IEP.…”