Content uploaded by Olatunji Olayiwola
Author content
All content in this area was uploaded by Olatunji Olayiwola on Jul 20, 2022
Content may be subject to copyright.
The application of Nano-silica gel in sealing well micro-annuli and cement channeling
Abstract
The possibility for hydrocarbon fluids to migrate through
debonded micro-annuli wells is a major concern in the
petroleum industry. With effective permeability of 0.1–1.0 mD,
the existence of channels in a cement annulus with apertures of
10–300 µm constitutes a major threat. Squeeze cement is
typically difficult to repair channels-leakage with small
apertures; hence, a low-viscosity sealer that can be inserted into
these channels while producing a long-term resilient seal is
sought. A novel application using nano-silica sealants could be
the key to seal these channels. In the construction and sealing
of hydrocarbon wells, cementing is a critical phase. Cement is
prone to cracking during the life cycle of a well because of the
changes in downhole conditions. The usage of micro-sized
cross-linked nano-silica gel as a sealant material to minimize
damaged cement sheaths is investigated in this study. Fluid
leakage through channels in the cement was investigated using
an experimental system. With a diameter of 0.05 inches, the
impact of the cement channel size was explored. The sealing
efficiency increased from 86 percent to 95 percent when the
nano-silica concentration of the sealing gel increased from 13
percent to 25 percent. This demonstrates that the concentration
of nano-silica in the sealing gel affects the gel's ability to seal
against fluid flow. This research proposes a new way for
improving cement zonal isolation and thereby lowering the
impact of cement failure in the oil and gas industry
... Recently nano-particle solutions have been studied to seal the cracks. The leak-off assessment of nanoparticle-stabilized CO 2 foams for fracture/crack applications was performed by Nguyen et al. (2022), Fu et al. (2022, and Olayiwola et al.(2022a). Olayiwola et al. (2022b) demonstrated promising properties of nanoparticle-based gels to seal fractures in lab conditions. ...
The leakage of hydrocarbon fluids through cracks in the annular cement and CO 2 storage is a major concern to the Petroleum Industry. A significant risk is posed when repairing leakage in a micro annuli channel with smaller apertures. A low-viscosity sealant that can generate a long-lasting resilient seal is desired. The solution to sealing these channels might lie in a novel application using nano-silica Gel. In this study, laboratory tests were carried out to examine the capabilities of nano-silica gels to seal the cracks. Analyzing its rheological property, the gel strengths of nano-silica gels were found to increase with an increase in nano-silica concentration. Additionally, it was discovered that as the concentration of nano-silica increases, the sealing and leakage pressures, defined as the pressures before and after water breakthrough, respectively, increase as well. With a typical 15% concentration of nano silica in gel, a sealing pressure gradient of 80.2 psi/in and a leakage pressure gradient of 30 psi/in at a leaking rate of 1 cc/min were noted. To validate the validity of the experimental results, a mathematical model was developed to predict the leakage rate of sealed fractures. The model suggests that the young’s modulus of sealant is a key property of nano-sealants and further investigations are needed to validate the mathematical model for quantitative use. This study suggests a novel strategy for enhancing cement zonal isolation and reducing cement failure in oil and gas sector.
... Yekeen et al. [5] presented a comprehensive review of NPs applications for hydraulic fracturing of unconventional reservoirs. NPs have recently been considered for sealing flow channels and cracks in wellbore cement sheath [6][7][8]. ...
Cement cracks are one of the most common failures in oil and gas wells. Cracks can reduce cement strength, resulting in a loss of zonal isolation and fluid leak. Placement of gels of nanoparticles (NPs) in the cracks is considered as a promising solution to solve the problem. It is highly desirable to know if the flow behavior of the NPs solutions is predictable when they are squeezed into the cracks. Experimental tests were performed in this study to investigate the flow behavior of nano-silica solutions in ducts of cross-sections of rectangular shape. The linear relationship between flow rate and pressure gradient and the calculated Reynolds number values suggests laminar flow in the ducts. However, the Hagen–Poiseuille correlation for laminar flow does not describe the flow behavior of the nano-silica solution. The classic hydraulic model with hydraulic diameter describes the nano-silica flow behavior with an average error of 12.38%. The cause of discrepancies between the flow models and the measured data is not known. It can be attributed to the NPs–NPs frictions and NPs–wall frictions in the rough ducts that were not considered in the flow models.
A cement crack is a typical cause of oil and gas well failure. Cracks weaken cement, reducing zonal isolation and fluid leakage. Nanoparticle (NP) gels are being tested for fracture treatment. When crushed into cracks, the flow behavior of NP problem solutions should be predicted. The potential efficacy of utilizing NP gels as a remedial measure for fractures is currently under investigation. It would be advantageous to determine if the flow behavior of solutions for NP problems can be anticipated when they are compressed into crevices. This study aimed to analyze the behavior of nano-silica solutions as they flow through ducts with rectangular cross-sections and varying crack dimensions. The introduction of NP solutions into the core leads to a decrease in pressure, which suggests that the nano-silica has been effectively transported through the crack. As the size of the fracture decreases, there is a corresponding increase in pressure drops, while the flow rate experiences a concurrent increase. This study presents responses of a pressure gradient to fluid concentration for a range of fracture widths, heights, and flow rates. The prediction of laminar flow in ducts is based on the linear correlation between the flow rate and the pressure gradient. Furthermore, the reduced pressure gradient indicates enhanced fluid flow within the fracture because of the amplified slot width. The fluid flow model proposed by Guo et al. (2022) was utilized to conduct a comparative analysis with the experimental data. Compared with test data, the model differs by roughly 90%. The technical cause of the flow model-observed data discrepancies is unknown. The flow model did not account for friction between NPs-NPs and NPs-walls in rough ducts. An empirical correlation has been found that quantifies the ratio as a function of nonsilica solution flow rate, cross-sectional geometry parameters, and nano-silica concentration. The correlation was calculated using nonlinear regression. The empirical relation and actual ratio have a significant correlation, as shown by R2 = 0.8965. In practice, Guo et al.’s (2022) hydraulic model’s pressure drops should be multiplied by the empirical correlation’s ratio to reduce errors.
ResearchGate has not been able to resolve any references for this publication.