Evaluation of Aminated Nano-Silica as a Novel Shale Stabilizer to Improve Wellbore Stability

Abstract

The issue of wellbore instability poses a significant challenge in the current exploration of shale gas reservoirs. Exploring more efficient shale stabilizers has always been a common goal pursued by researchers. In this paper, a novel shale stabilizer, denoted as ANS, was prepared by employing a silane-coupling modification method to graft (3-Aminopropyl) triethoxysilane (APTES) onto the surface of nano-silica. The structure of ANS was characterized through Fourier transforms infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), and particle size tests (PST). The shale stabilizing properties of ANS were evaluated through tests such as pressure penetration, BET analysis, hydration expansion and dispersion. Furthermore, the interaction between ANS as a shale stabilizer and clay was explored through clay zeta potential and particle size analysis. The results indicated that ANS exhibited a stronger plugging capability compared to nano-silica, as evidenced by its ability to increase the shale pressure penetration time from 19 to 131 min. Moreover, ANS demonstrated superior hydration inhibition compared to commonly used KCl. Specifically, it reduced the expansion height of bentonite from 8.04 to 3.13 mm and increased the shale recovery rate from 32.84% to 87.22%. Consequently, ANS played a dual role in providing dense plugging and effective hydration inhibition, contributing significantly to the enhancement of wellbore stability in drilling operations. Overall, ANS proved to be a promising shale stabilizer and could be effective for drilling troublesome shales.

Development and Characterization of the Shale Stratum Well Wall Stabilized with Nanosomal Sealing Agent

“…The siloxanes and hydroxyl groups on the surface of SiO 2 give it significant hydrophilicity, and there are intermolecular forces leading to the strong aggregation of SiO 2 [ 3 ]. Therefore, the biggest challenges faced in the preparation and application processes of polymer/inorganic nanoparticle composites are in ensuring an adequate dispersion of inorganic nanoparticles in the polymer matrix and strengthening the interaction between the polymer matrix and inorganic nanoparticles [ 25 ].…”

“…"β" is a parameter that quantifies the static compressibility of a fluid, with its unit being MPa −1 . "V" represents the volume of the downstream container, specifically in units of cm 3 . "L" refers to the length, with its unit being cm.…”

“…Due to the highly developed, weak surface structures, such as the nanoscale microcracks and bedding planes in shale formations, as well as their strong water sensitivity, serious wellbore stability problems are prone to occur during long horizontal drilling [ 1 , 2 , 3 , 4 ]. In shale formations, their inherent porosity and permeability are both at extremely low levels.…”