Cationic starch derivatives as reactive shale inhibitors for water‐based drilling fluids

Abstract

One of the major problems associated with the use of water‐based drilling fluids is the interaction of water with specific rock formations, such as shales, and the consequent swelling of reactive clays that may be present in that type of rock. Several types of clays reactivity inhibitors have been used by the oil industry, and the most effective ones are the cationic polyelectrolytes, such as the poly(diallyldimethylammonium chloride) (PDADMAC). However, this polyelectrolyte is very toxic. In this work, a series of cationic starch derivatives with different cationic degrees were synthesized with the objective of evaluating their potential as environmentally correct shale reactivity inhibitors. The results showed that the synthesized derivatives presented a good capacity of adsorption on bentonite and an efficient inhibition of the shale reactivity. The derivative with an intermediate cationic degree presented the best performance. In the tests with the formulated fluids this derivative provided an intact cuttings recovery of 84.8% and a total recovery of 92.3%. These values are very close to those found for the PDADMAC additive, therefore indicating that this cationic starch derivative presents a good potential as inhibitor of the shale reactivity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46621.

Poly-l-arginine as a High-Performance and Biodegradable Shale Inhibitor in Water-Based Drilling Fluids for Stabilizing Wellbore

“…Therefore, the development of high-performance WBDFs with environmentally friendly performance has attracted much interest. , Various additives have been introduced and researched. ,, As important additives for WBDFs, environmentally friendly shale inhibitors are also essential. In recent decades, various shale inhibitors or stabilizers , have been developed, such as potassium salts, nanoparticles, − polyalcohols, amine, and its derivatives, − cationic copolymers, , and some natural materials. − Besides, some shale inhibitors with low environmental footprints have been also researched, including acrylamides, glycols, biomolecules, and silicates . However, it is seldom that these inhibitors can simultaneously consider excellent environmental performance and efficient inhibition.…”

Modified Biosurfactant Cationic Alkyl Polyglycoside as an Effective Additive for Inhibition of Highly Reactive Shale

“…The use of shale inhibitors in WBM is an important approach to enhance the shale inhibition property and reduce wellbore instability. The conventional shale inhibitors include inorganic salts, , surfactants, − polymers, − and alcohols . KCl is the most commonly used shale inhibitor in the field because K + has a lower hydration energy and can migrate to interlayer spaces of clays and remain bound to the clay surface, leading to decreased swelling.…”

“…The positive ions of cation surfactants , could adsorb on the surface of shale by electrostatic attraction and the hydrophobic tails could reverse the wettability of the shale surface, prevent water invasion, and reduce shale hydration. Cation polymers could coat the surface of shale by electrostatic attraction, forming films to prevent water invasion. Polyamines are a new generation shale inhibitor, which are being studied intensively worldwide. − Zhong et al found that polyether diamine is effective in inhibiting shale hydration by coating of clay particles, modification of the clay surface, and so forth.…”

Influence of Hydrophobically Modified Polymer and Titania Nanoparticles on Shale Hydration and Swelling Properties

“…However, the use of OBM is restricted due to strict environmental regulations, high cost, disposal problems, and lower performance in the well logging process. − Therefore, WBM is widely used for the drilling of oil and gas wellbores. Around 80% of wellbore drilling is attained through WBM due to its lesser cost, easy preparation for a wellbore formation, environmental friendliness, easy recycling, and improved performance in the well logging process. − However, the active water molecules in the WBM interact with the sensitive shale formations and result in the swelling and dispersion of shale in the wellbore, which often leads to the loss of billions of dollars in the drilling process. , Therefore, several WBM additives which are used as shale swelling and dispersion inhibitors include polymers, ,− nanoparticles, − amines, − and polymer nanocomposites, − employed to reduce wellbore instability problems.…”