X-ray Computed Tomography (CT) to Scan the Structure and Characterize the Mud Cake Incorporated with Various Magnetic NPs Concentration: An Application to Evaluate the Wellbore Stability and Formation Damage

Abstract

The X-ray computed tomography method has provided unrivalled data about the characterization and evolution of the internal/external structure of materials by analyzing CTN and non-destructive imaging approach. Applying this method on the appropriate drilling-fluid ingredients plays a significant role in generating proper mud cake quality to stabilize wellbore, and avoid formation damage and filtration loss by preventing drilling fluid invasion into the formation. In this study, smart-water drilling mud containing different concentrations of magnetite nanoparticles (MNPs) was used to assess the filtration loss properties and formation impairment. Conventional static filter press, non-destructive X-ray computed tomography (CT) scan images and high-resolution quantitative measurement of CT number method were used to estimate the filtrate volume and characterize the filter cake layers, hence evaluating the reservoir damage through hundreds of merged images. The CT scan data were combined with the HIPAX and Radiant viewer digital image processing. The variation in CT number of mud cake samples under different concentrations of MNPs and without MNPs concentration were analyzed, and hundreds of 3D images as a cross-sectional profile were used. This paper highlights the importance of MNPs property in terms of minimizing filtration volume and improving mud cake quality and thickness, and hence improving the wellbore stability. From the results, a notable reduction of filtrate drilling mud volume and mud cake thickness to 40.9% and 46.6%, respectively, were recorded for drilling fluids incorporated with 0.92 wt.% of MNPs. However, this study asserts that optimal MNPs should be implemented to guarantee the best filtration property. As confirmed from the results, increasing the MNPs concentration beyond the optimal value (up to 2 wt.%) increased the filtrate volume and mud cake thickness by 3.23 and 33.3%, respectively. CT scan profile images show two layers of mud cake produced from water-based drilling fluids possessing 0.92 wt.% MNPs. The latter concentration was found to be the optimal additive of MNPs as it caused a decrease in filtration volume, mud cake thickness, and pore spaces within the structure of the mud cake. Using the optimum MNPs, the CT number (CTN) shows a high CTN and density material, and uniform compacted thin mud cake structure (0.75 mm). The produced thin mud cake layer reveals the precipitation or exchange of elemental/mineral composition during fluid-solid interaction. These results confirm that MNPs could help in avoiding or reducing the formation damage, driving away drilling fluid from the formation, and improving borehole stability.

Comprehensive Review on the Recent Advancements in Nanoparticle-Based Drilling Fluids: Properties, Performance, and Perspectives

“…Effects of metal oxide NPs on filter cake properties, reduced fluid loss observed by various studies, and optimal NP concentration in drilling fluids are reviewed subsequently. Faisal et al investigated the effect of magnetic NPs in the pore-plugging phenomenon in mud cake through X-ray computed tomography (CT) Figure a illustrates the CT scan results of a mud cake sample prepared from drilling fluid containing 0.92 wt % magnetic NPs (MNPs).…”

“…Faisal et al investigated the effect of magnetic NPs in the pore-plugging phenomenon in mud cake through X-ray computed tomography (CT). 66 structure, highlighting the significant role of MNPs in enhancing mud cake texture and stability. Figure 10c (i−iv) illustrates the impact of different concentrations of magnetic NPs (MNPs) on the structure and quality of mud cakes as observed through X-ray CT scan data.…”

“…Works of literature published by Larson et al, Su et al, and many more confirm that graphene can be used as a shale swelling inhibitor 66,87. According to Nair…”

Study on the Behavior and State of Viscous Fractured Leakage Bridging and Plugging Slurry during the Pump-In and Pressurization Process

“…Fracture-induced losses contribute to over 90% of the overall cost of controlling such losses [1]. As the main direction of oil and gas production gradually shifts towards unconventional reservoirs such as tight oil and shale gas with enormous resource potential, the development of fracture systems in these unconventional reservoirs has brought complex situations in controlling fluid-induced fracture losses [2,3]. The existing research on fracture loss mainly focuses on rock anisotropy, stratigraphy and fracture development, but the research on slurry plugging behavior during pumping is relatively limited, resulting in a lack of understanding of the change in slurry plugging in the lost layer [2,3].…”

“…As the main direction of oil and gas production gradually shifts towards unconventional reservoirs such as tight oil and shale gas with enormous resource potential, the development of fracture systems in these unconventional reservoirs has brought complex situations in controlling fluid-induced fracture losses [2,3]. The existing research on fracture loss mainly focuses on rock anisotropy, stratigraphy and fracture development, but the research on slurry plugging behavior during pumping is relatively limited, resulting in a lack of understanding of the change in slurry plugging in the lost layer [2,3]. The behavior of plugging slurry during static and pumping-squeezing states significantly affects the efficiency and accuracy of fracture sealing and bridging, while the settlement of weighting materials under the influence of gravity can lead to wellbore losses, stuck pipes, well control and cementing operation difficulties [4,5].…”