Design and fabrication of a Preformed Thixotropic-Viscoelastic Nanocomposite hydrogel system (PNCH) for controlling sand production in reservoirs

In this study, the performance of preformed dual crosslinked nanocomposite hydrogels (PNCH) consisting of acrylamide, 2-acrylamide-2-methylpropane sulfonic acid, maleic acid, and acrylic acid in sand control was investigated. Also, the effects of three nanoparticles (NPs) of iron (PNCH1), silicon (PNCH2), and bentonite (PNCH3) on the PNCH structure were studied. The morphology, equilibrium swelling ratio (ESR), rheology, thermal strength, zeta potential, and compressive strength were experimentally analyzed. According to the XRD results, the NPs were completely dispersed in all three samples. The results of SEM and EDS tests confirmed the presence of NPs within the PNCHs with a dense, homogeneous, and porous structure. The results of the ESR at distilled and formation water at ambient temperature for PNCHs (1), (2), and (3) were (13.9,4.55), (15.45, 6.35), and (12.9, 4.8), also at reservoir temperatures ESR results were reported (78, 17.5), (89, 13), and (70,12.9) respectively. From the TGA results, structure destruction of PNCHs starts at 222, 225, and 202 °C respectively so the addition of 1 wt% of NPs increased the structure destruction from nearly 80 °C to more than 200 °C. Based on the results of the strain sweep test, structures of PNCHs can cause viscoelastic behavior with the maximum elastic modulus of 29,000, 8430, and 10,800, and critical strain of (10%, 19.3%, and 10.8%) respectively. The loop test results confirmed the time-dependent viscoelastic properties of thixotropic in all structures. Finally, in compressive strength test revealed that adding 0.5 pore volume of 1 wt% of PNCH into the sandpack increased its strength by 980%

Synthesis of Cobalt nanocomposite hydrogel based on Acrylamide as an efficient chemical for sand control in the oil reservoir

Hypothesis: Sand production from oil reservoirs is marked by many problems, such as well productivity reduction, operating equipment corrosion, and an increase in production costs; therefore, sand control in unconsolidated reservoirs is crucial for operating companies. Chemical injection into the production vessel, in order to strengthen and reduce sand formation, would be one of the most important methods of sand control.Methods: In this study the effectiveness of a Co[AM-AMPS-AAC]/PEI-MBA(CO) hydrogel nanocomposite in sand control was investigated. The acrylamide-based nanocomposite is strengthened structurally and thermally by the addition of double crosslinkers and nanoparticles. Structural, morphological, thermal, rheological, compressive strength and flooding tests were carried out to define and assess its efficacy.Findings: According to X-ray diffraction test findings, nanoparticles are evenly distributed throughout the structure. Morphological tests demonstrated the production of a dense, homogenous, and porous structure and validated the presence of nanoparticles in the structure. According to the thermal gravimetric test, adding nanoparticles increased the starting temperature of degradation from 80 to 195°C. The strain and frequency sweep rheological tests investigated the behavior of the material under different strains and stresses; they confirmed the preservation of the strong structure and linear viscoelastic behavior at a temperature of 90°C, strains between 0.1 and 20%, and frequencies between 0.1 and 10 Hz. The injection of 0.5 PV (pore volume) of 1% (by wt) nanocomposite to the sand pack resulted in a 730% increase in the axial strength of the sand pack according to the compressive strength test and 90% reduction in sand production measured by the chemical flooding test. Considering the stability and proper efficiency in the reservoir's harsh conditions, having linear viscoelastic properties, increasing compressive strength, and reducing sand production, the hydrogel nanocomposite designed in this research is proposed as a new and optimal product to control sand production and migration