Highly Efficient Modified Activated Carbon as Shale Inhibitor for Water Based Drilling Mud Modification

Abstract

Maintaining wellbore stability while drilling is critical to mitigate operational problems and reduce well construction costs. This is clearly evident in the case of drilling troublesome intervals such as shale formations. The current study describes the effect of diethylenetriamine modified activated carbon (DETA-AC) on the swelling inhibition of shale samples with high clay content and rheological features of water-based muds (WBM). DETA-AC provides a huge surface area, a prominent number of functional groups, and a relatively non-toxic nature that makes it suitable for environment-friendly additives to drilling fluids. In the current study, the DETA-AC was utilized as an environment-friendly swelling inhibitor. Rheology tests were conducted by hot rolling the WBM at 212°F temperature and 500 Psi pressure for 16 hours. The inhibition features were assessed by dispersion recovery test, shale inhibition stability test, and linear swelling test. The outcomes revealed that DETA-AC modified WBM (DETA-AC-WBM) showed high shale recovery (93.3 %) in dispersion test as related to unmodified WBM (73.6 %), the aqueous solution of KCl (51.5 %), and commercial shale inhibitor mud (74.9%). shale cuttings treated with DETA-AC-WBM displayed stable behavior and resistance against water for up to 2 days. Bentonite in DETA-AC-WBM demonstrated a prominent decrease in linear swelling 58 % as compared to bentonite in water. While the rheological characteristics of DETA-AC-WBM remain almost the same after hot rolling. To confirm the adsorption of DETA-AC on the surface of the clay, its inhibition mechanism was explored by several characterization techniques such as Fourier transforms infrared spectroscopy (FT-IR) analysis, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-Ray spectroscopy. The proposed inhibition mechanism suggests that DETA-AC carries functional groups that can disturb the hydrogen bonding among H2O and shale material. Subsequently, the clay surface is protected against the adverse effects of clay-water interactions.

An Experimental Study and Machine Learning Modeling of Shale Swelling in Extended Reach Wells When Exposed to Diverse Water-Based Drilling Fluids

“…Oil-based drilling fluids (OBDFs) have been effective in controlling various aspects of drilling operations, such as shale swelling, lubrication, temperature resistance, and corrosion control. − However, OBDFs are not favored due to environmental concerns, high costs, and limitations for well logging, especially in offshore drilling operations . On the other hand, WBDFs commonly known as muds, are widely employed due to their environmentally friendly nature, ease of preparation, and effective inhibition of shale hydration and swelling. − The interaction between these fluids and shale formations can cause shale swelling due to water absorption by the shale rocks. The swelling behavior of shales can vary significantly depending on the mineral composition, organic content, temperature, pressure, and other geological factors. − The risk of shale swelling in extended reach wells is particularly challenging because of the longer wellbore sections and the increased exposure of shale formations to drilling fluids .…”

Advances in Carbon Nanostructures and Nanocellulose as Additives for Efficient Drilling Fluids: Trends and Future Perspective—A Review

“…Drilling fluids play a very crucial role in the drilling process, because of their multifunction, such as lubricant, cleaning of the wellbore, carrying the shale cuttings, sustaining wellbore stability, shale inhibition, the formation of filter cake, and fluid loss control. The efficient drilling operation is greatly dependent on the consistency of drilling fluid properties. , The understanding of drilling fluid characteristics can immensely help to develop and design a drilling fluid system with improved features and that can get the better of problems faced during the nontraditional drilling process. The drilling fluid must be engineered to work efficiently under continuously changing drilling conditions. , …”

“…The efficient drilling operation is greatly dependent on the consistency of drilling fluid properties. 5,6 The understanding of drilling fluid characteristics can immensely help to develop and design a drilling fluid system with improved features and that can get the better of problems faced during the nontraditional drilling process. The drilling fluid must be engineered to work efficiently under continuously changing drilling conditions.…”