Use of Nanoparticles in Completion Fluids as Dual Effect Treatments for Well Stimulation and Clay Swelling Damage Inhibition: An Assessment of the Effect of Nanoparticle Chemical Nature

Abstract

The objective of this study is to evaluate the role of nanoparticles with different chemical structures in completion fluids (CF) in providing a positive dual effect for well stimulation and clay swelling damage inhibition. Six types of commercial (C) or synthesized (S) nanoparticles have been incorporated into a commercial completion fluid. Doses varied between 100 and 500 mg·L^-1. CF-nanoparticles were evaluated by fluid-fluid, fluid-nanoparticle, and fluid-rock interactions. The adsorption isotherms show different degrees of affinity, which impacts on the reduction of the interfacial tension between the CF and the reservoir fluids. Fluid-fluid interactions based on interfacial tension (IFT) measurements suggest that positively charged nanoparticles exhibit high IFT reductions. Based on contact angle measurements, fluid-rock interactions suggest that ZnO-S, SiO₂-C, SiO₂-S, and ZrO₂ can adequately promote water-wet rock surfaces compared with other nanomaterials. According to the capillary number, ZnO-S and MgO-S have a higher capacity to reduce both interfacial and surface restrictions for crude oil production, suggesting that completion fluid with nanoparticles (NanoCF) can function as a stimulation agent. The clay swelling inhibition test in the presence of ZnO-S-CTAB and MgO-S-CTAB nanoparticles showed a 28.6% decrease in plastic viscosity (PV), indicating a reduction in clay swelling. The results indicate that a high-clay environment can meet the completion fluid's requirements. They also indicate that the degree of clay swelling inhibition of the nanoparticles depends on their chemical nature and dosage. Finally, displacement tests revealed that CF with nanoparticles increased the oil linear displacement efficiency.

Keywords: adsorption; clay swelling; completion nanofluid; interfacial tension; nanoparticles; wettability.

Figure 1

Schematic assembly of an optical tensiometer for contact angle measurements: (1) high-resolution camera, (2) sample support, and (3) droplet injection system.

Figure 2

Experimental setup for the coreflooding tests: (1) test tube for sampling, (2) sample holder, (3) rock sample core, (4) cylinder, (5) syringe pump.

Figure 3

FTIR analysis for: (a) SiO₂-C (blue curve) and SiO₂-S (orange curve); (b) Al₂O₃-C (grey curve) and ZrO₂-C (yellow curve); (c) MgO-S (purple curve) and ZnO-S (green curve).

Figure 4

Adsorption isotherms at 25 °C and fixed surfactant dosage ranging from 0 to 5000 mg·L⁻¹ for SiO₂-C (blue dots), Al₂O₃-C (grey dots), ZrO₂-C (yellow dots), MgO-C (grey dots), SiO₂-S (orange dots), and ZnO-S (green dots), along with SLE model fitting (continuous black line).

Figure 5

Contact angle values at 25 °C for sandstone surface treated with MgO-S, ZnO-S, SiO2-S, Al2O3-C, ZrO2-C, and SiO₂-C for dosages of (a) 100 mg·L⁻¹, (b) 300 mg·L⁻¹, and (c) 500 mg·L⁻¹.

Figure 6

IFT values for measurements between crude oil and NanoCF-based MgO-S, ZnO-S, SiO₂-S, SiO₂-C, Al₂O₃-C, and ZrO₂-C for 100, 300, and 500 mg·L⁻¹.

Figure 7

Capillary numbers for completion fluid (CF): base (black bar), MgO-S (purple bars), ZnO-S (green bars), ZrO₂-C (yellow bars), Al₂O₃-C (grey bars), SiO₂-S (orange bars), and SiO₂-C (blue bars) at nanoparticle dosages of 100, 300, and 500 mg·L⁻¹.

Figure 8

Relationship between the capillary number and the point of zero charge (pH_pzc).

Figure 9

Clay swelling inhibition results through the rotational viscosimeter method for (a) deionized water (DW) and nanoparticle-free CF; and (b) nanoparticle-free CF and NanoCF.

Figure 10

(a) Contact angles at 25 °C for sandstone treated with CF-containing surface- and non-surface-modified nanoparticles with CTAB. (b) Interfacial tension (IFT) values for measurements between crude oil and CF-containing surface- and non-surface-modified nanoparticles with CTAB. (c) Capillary number for CF-containing surface- and non-surface-modified nanoparticles with CTAB. (d) Clay swelling inhibition results through the rotational viscosimeter method for CF-containing surface- and non-surface-modified nanoparticles with CTAB. Nanoparticle concentration: 100 mg·L⁻¹.

Figure 11

Oil linear displacement efficiency curves at atmospheric conditions for the base (blue symbols) and the selected NanoCF with ZnO-S-CTAB nanoparticles at 100 mg·L⁻¹ (orange symbols).