Synthesis of an Eco-Friendly Xylooligosaccharides and Its Mechanistic Evaluation in Water-Based Drilling Fluids

Abstract

This study investigates the preparation and application mechanism of Xylooligosaccharides (XOS), an environmentally friendly oligosaccharide additive derived from black fungus in water-based drilling fluids (WBFs). The distinctive molecular characteristics of XOS are revealed through Fourier-transform infrared spectroscopy. Thermogravimetric analysis confirms its stability at temperatures below 150 °C. In terms of performance enhancement, incorporating XOS improves rheological properties and filtration efficiency. Elevated XOS concentrations increase viscosity, diminish fluid loss, suppress clay hydration, and enhance cohesive strength, especially at higher temperatures. Additionally, incorporating XOS prompts the formation of a lubricating layer on particle surfaces, facilitating improved interaction between particles and the surrounding fluid. This layer substantially reduces friction coefficients, thereby significantly boosting the lubrication efficiency of the drilling fluid. At the microstructural level, the incorporation of XOS leads to noticeable microstructural refinement in the matrix mud cake, resulting in a smoother particle distribution due to interactions between XOS and particles. Mechanistically, introducing XOS results in a significant shift in the distribution of clay particle sizes. This phenomenon can be attributed to XOS’s ability to create a stable hydration film within the WBFs. As a result, this film mitigates particle aggregation, leading to a reduction in particle size. XOS emerges as a versatile and sustainable oligosaccharide inhibitor, effectively optimizing the performance of WBFs. Its diverse contributions to lubrication, inhibition, and microstructure refinement position XOS as a promising solution for efficiently extracting oil and gas resource.

1. Introduction

The increasing demand for energy resources has led to a substantial rise in global drilling operations. As a result, there is a growing interest in formulating eco-friendly drilling fluids that retain necessary performance attributes while minimizing negative environmental impacts. Water-based drilling fluids (WBFs) are regarded as environmentally friendlier alternatives than oil-based and synthetic fluids owing to their reduced toxicity and increased biodegradability. Nevertheless, WBFs frequently face performance limitations compared to oil-based drilling fluids, including low viscosity, inadequate lubrication, limited temperature resistance, and insufficient shale inhibition [1,2]. Diverse additives, such as polymers, surfactants, and weighting agents, are frequently used to address these limitations [3,4,5]. While these additives improve WBF performance, many originate from non-renewable sources, presenting environmental risks. In particular, the WBFs utilized in high-temperature deep wells pose a range of environmental challenges, including the dark coloration of discarded drilling fluid, elevated chemical oxygen demand (COD), limited biodegradability, generation of Benzopyrene under high-temperature conditions, substantial treatment expenses, and the intricate task of reconciling environmental preservation with high-temperature resilience [6,7]. As a result, developing high-temperature-resistant and environmentally friendly novel materials stands out as one of the utmost technical challenges in efficiently extracting deep oil and gas resources.

Environmentally friendly agents for treating WBFs can be categorized into diverse types, encompassing starch, cellulose, polysaccharides, humic acid, tannin extract, natural plant extracts (surfactants), plant material modification, artificially synthesized small molecule polymers, dopamine, and inorganic salts. Leonardo dos Santos Cescon et al. [8] employed a cationic etherifying agent to modify corn starch, producing cationic starch with varying degrees of substitution. This starch displayed favorable adsorption capacity and inhibitory effects. Zhang et al. [9] created cationic cellulose with a high degree of substitution, demonstrating inhibitory properties and the capability to minimize filtration losses. An et al. [10] revealed that chitosan’s quaternary ammonium cation can hinder clay hydration using adsorption, intercalation, and encapsulation. Ma et al. [11] conducted a condensation reaction between L-arginine and chitosan molecules using EDC/NHS, thus elevating adsorption capacity. Xuan et al. [12] noted that dopamine can adhere to the clay surface and counteract the negative charge of clay particles. This process results in the compression of the clay’s double layer and the consequent suppression of clay hydration and expansion. Aghil Moslemizadeh et al. [13,14,15], Seyed Reza Shadizadeh et al. [16], Fan Zhang et al. [17], Khezerlooe-ye Aghdam et al. [18], and Barati Pezhman et al. [19] isolated plant saponins from different natural plant species. They observed that the hydrophilic glycosides within these saponins can adhere to the clay surface through hydrogen bonding. Simultaneously, the hydrophobic aglycone can create an external hydrophobic barrier, impeding clay hydration. Mei Chun Li et al. [20] explored the filtration-reducing impact of soybean protein isolate (SPI). Du et al. [21] analyzed several natural plant materials containing polysaccharides. They identified various effects of these materials, including reduced filtration loss, enhanced lubrication, and suppressed clay hydration. Su et al. [22] and Jia et al. [23] examined the utilization of cellulose derivatives such as Carboxymethyl cellulose and hydroxyethyl cellulose as viscosity regulators and shale inhibitors in WBFs. Moreover, the feasibility of chitosan, a natural polysaccharide, as a biopolymer in such fluids has been investigated, given its capacity to improve rheological traits and impede shale hydration [24,25].

Xylooligosaccharides (XOS) represent a compelling eco-friendly [26] and sustainable solution for enhancing water-based drilling fluids (WBFs). Their affordability and widespread availability, sourced from agricultural by-products, align with green chemistry principles, minimizing resource wastage and production costs. The distinct molecular structure of XOS, comprising 2-7 xylose molecules arranged in β-oligosaccharides connected via 1,4-glycosidic bonds, underpins their exceptional attributes [27,28,29]. This unique configuration enhances temperature resistance within drilling fluids. The hydroxyl groups on XOS molecules facilitate interactions through hydrogen bonding, ensuring steadfast molecular arrangements and bolstering resilience at elevated temperatures [30,31]. This inherent temperature resistance, coupled with a green synthesis approach, positions XOS as a promising candidate for WBF enhancement. However, unlocking the full potential of XOS in drilling fluids demands innovation and deeper insights into their performance attributes and impact mechanisms.

This article introduces a pioneering synthesis approach for eco-friendly XOS and comprehensively evaluates its application within WBFs. Our primary objective is to investigate the potential advantages of this improved XOS variant and gain profound insights into its impact mechanisms on WBFs, ultimately driving innovation in sustainable drilling fluid technology. While these promising outcomes inspire confidence, further research is necessary to formulate novel XOS variants with enhanced performance attributes and to deepen our understanding of their potential impact mechanisms in WBFs.

2. Materials and Methods

2.1. Materials

The black fungus samples utilized in this study were sourced from a reputable supplier, Metro Supermarket, to ensure consistency in the sample quality and origin. Ethanol (AR, ≥95%) and hydrochloric acid (AR, 36.0~38.0%) of high purity were procured from Shanghai Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China), further ensuring the reliability and precision of the experimental procedures. The sodium bentonite (Na-Mt) employed as a crucial component in the formulation of Water-Based Drilling Fluids (WBFs) was acquired from China Bohai Drilling Co., Ltd. (Tianjin, China). This choice of supplier was made to guarantee the consistency and reliability of the base mud composition and properties used in the experiments. For the cuttings recovery tests, outcrop shale samples were generously provided by Chuanqing Drilling Engineering Co., Ltd. (Chengdu, China), ensuring that the test materials closely represented real-world drilling conditions and scenarios. Chemicals including potassium chloride (AR), sodium chloride (AR), and sodium carbonate (AR), which played essential roles in the formulation of drilling fluids, were supplied by Aladdin Pharmaceutical Co., Ltd. (Shanghai, China), maintaining the quality and purity standards required for rigorous laboratory investigations. The polyamine inhibitor SDJA, a critical component for inhibiting clay swelling and improving the performance of drilling fluids, was synthesized by the esteemed research team at China University of Petroleum (East China). This proprietary inhibitor was specifically tailored to meet the stringent requirements of the study, ensuring its effectiveness in the experimental setup.

2.2. Preparation of XOS

Black fungus samples, procured from a food market, were finely crushed using a grinder to optimize extraction efficiency. These ground particles were introduced into a suitable 3.0% hydrochloric acid solution. The mixture underwent gentle stirring at 200 r/min to facilitate the liberation and dissolution of XOS. Subsequently, the resulting ex-traction solution was subjected to multiple filtration steps using a filtration device to eliminate solid residues and impurities. Finally, the filtrated XOS extract was dried at 55 ℃ in a vacuum drying oven and sieved through a 200-mesh screen to obtain XOS powder...

2.3. Structural Characterization and Mechanism Analysis Methods

In this study, a comprehensive characterization of Xylooligosaccharides (XOS) was conducted using a range of advanced analytical techniques to gain valuable insights into their molecular structure, thermal stability, particle size, and micromorphology. The molecular structure of XOS was elucidated through Fourier-transform infrared spectroscopy (FT-IR), employing state-of-the-art equipment from Shimadzu Enterprise Management (Beijing Branch) Co., Ltd. (Beijing, China). FT-IR spectroscopy is a powerful tool that allows for the detailed analysis of chemical bonds and functional groups within a substance, providing critical information about the structural composition of XOS. To assess the thermal stability of XOS, a rigorous analysis was performed using a Mettler-Toledo TGA-2 thermogravimetric analyzer (Mettler Toledo Technology (China) Co., Ltd., Shanghai, China). This analysis involved subjecting the XOS samples to controlled heating at a rate of 10 K/min under a protective nitrogen atmosphere. The thermogravimetric analysis provided crucial data on the temperature-dependent weight loss and decomposition behavior of XOS, offering insights into their thermal properties. Particle size analysis of XOS was conducted using the cutting-edge MALVERN MS3000 instrument (Malvern Panalytical Ltd., Malvern, UK). This analysis allowed for the precise determination of particle size distribution, which is essential for understanding the physical characteristics of XOS and their suitability for various applications. Furthermore, the micromorphology of the mud cake, an integral component of drilling fluid systems, was examined in detail. This assessment was carried out using the ZEISS EVO LS-15 Scanning Electron Microscope (SEM) from Carl Zeiss AG (Oberkochen, Germany).

2.4. Methods

2.4.1. Rheological Properties Tests

The rheological characteristics of the bentonite/XOS mud were assessed using a six-speed rotary viscometer (ZNN-D6 type, Qingdao Haitongda Special Instrument Co., Ltd., Qingdao, China) to ensure precise measurements. Following that, the apparent viscosity (AV), plastic viscosity (PV), and yield point (YP) were calculated using the formulas provided in the API recommended practice for the standardized field testing of drilling fluids.

$${\mathrm{AV}=\mathsf{\theta }}_{600}/2(\mathrm{mPa}·\mathrm{s})$$

(1)

$${\mathrm{PV}=\mathsf{\theta }}_{600}-{\mathsf{\theta }}_{300}(\mathrm{mPa}·\mathrm{s})$$

(2)

$${\mathrm{YP}=(\mathsf{\theta }}_{300}-\mathrm{PV})/2(\mathrm{Pa})$$

(3)

2.4.2. API Filtration Tests

The filtration efficiency of the bentonite/XOS mud was assessed through API filtrate tests utilizing an SD-3-type medium-pressure filtration apparatus (Qingdao Tongchun Machinery Petroleum Instrument Ltd., Qingdao, China). The filtrate volume from the mud was determined using a filter press fitted with filter paper, maintained at a constant pressure of 100 psi for 30 min.

The preparation procedure for the bentonite/XOS mud included multiple steps. Firstly, 16 g of sodium bentonite was introduced to 400 mL of tap water and mixed into a base mud (4.0%) using low-speed stirring. Subsequently, the suspension was centrifuged by a high-speed agitator at 8000 rpm for 30 min. The base mud was sequentially supplemented with 1.2 g of anhydrous sodium carbonate and a specific quantity of XOS for the filtration characteristics and rheology tests. The mixture was stirred at 6000 rpm for 20 min, followed by a 24 h resting period to ensure adequate bonding. Finally, the base mud utilized for the aging experiment was formulated using a GW300-PLC-type roller oven (Qingdao Tongchun Petroleum Instrument Co., Ltd. Qingdao, China) with a heating duration of 16 h at 150 °C.

2.4.3. Lubrication Performance Tests

The lubrication performance of the drilling fluid is evaluated using the EP-2 extreme pressure lubrication instrument, which enables the observation of friction characteristics and data recording by applying different loads. This process comprehensively assesses the effectiveness and stability of the drilling fluid’s lubrication under various conditions.

2.4.4. Inhibition Performance Tests

To rigorously evaluate the inhibitory effects of Xylooligosaccharides (XOS) on clay hydration dispersion under high-temperature conditions, we conducted a repeated rolling recovery experiment designed to closely mimic real-world drilling site scenarios. In the experimental procedure, we introduced natural rock debris into a solution containing XOS. The XOS-laden solution and rock debris were subjected to a rigorous high-temperature rolling process, precisely set at 150 °C, which simulated the elevated temperatures encountered during drilling operations. This high-temperature rolling was meticulously carried out for an extended duration, spanning 16 h. To ensure the reliability and comprehensiveness of our findings, we repeated the hot rolling process three times consecutively. After each iteration, the rock debris was meticulously extracted, carefully weighed, and the corresponding results were diligently recorded. This repeated rolling recovery experiment was instrumental in assessing the cumulative impact of XOS on clay hydration dispersion, reflecting the progressive effects over successive cycles. By conducting this rigorous and repeated experiment, we aimed to obtain a comprehensive understanding of how XOS influences clay hydration and dispersion under challenging high-temperature conditions, providing valuable insights into its effectiveness as an inhibitory agent in drilling fluid systems.

2.5. Environmental Performance Tests

We evaluated the environmental protection performance of the XOS solution, which included assessing the effective concentration 50% (EC₅₀), Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD₅).

3. Results and Discussion

3.1. Structural Characterizations of XOS

3.1.1. FT-IR Spectroscopy Analysis

As shown in Figure 1, The peak around 3399.5 cm⁻¹ usually corresponds to the vibration of hydrogen-bonded hydroxyl groups (-OH). In XOS, vibrations originate from hydroxyl groups or water molecules on polysaccharide chains. The peak around 2809.5 cm⁻¹ is recognized as the stretching vibration of methyl (-CH₃). The peak around 2717.5 cm⁻¹ is recognized as the stretching vibration of methylene (-CH₂). The peak around 1592.8 cm⁻¹ usually corresponds to the stretching vibration of non-conjugate C=C and is identified as the unsaturated carbon–carbon bond in XOS. The peaks around 1383.5 cm⁻¹ are identified as hydroxyl and methyl bending vibrations, corresponding to the bending vibrations of C-H in XOS. The peak around 1351 cm⁻¹ usually corresponds to the stretching vibration of the carboxyl group (C=O), which is recognized as caused by aldehyde or ketone groups in XOS. The peak around 1112.2 cm⁻¹ was identified as the stretching vibration of the C-O-C bond in XOS and the stretching vibration of C-OH. The peak around 766.1 cm⁻¹ was identified as C-H bending vibration in XOS. The peak around 618.5 cm⁻¹ was identified as the stretching vibration of the C-O-C bond and some C-C bonds in XOS.

3.1.2. Thermogravimetric

As shown in Figure 2, between 40 °C and approximately 100 °C, the mass percentage decreases due to the evaporation of water adsorbed by plant polysaccharides. With rising temperature, water gradually evaporates, reducing the mass percentage, while plant polysaccharides remain undecomposed. The mass percentage decreases significantly as the temperature reaches around 150 °C. At this temperature, the bonds between the long-chain structural molecules of plant polysaccharides begin to break down, leading to the decomposition or evaporation of some plant polysaccharides and consequently reducing the mass percentage. In the temperature range between 150 °C and 235 °C, the mass percentage decreases from 93% to 81%, indicating that the molecular structure of plant polysaccharides after bond breaking remains relatively stable. When the temperature exceeds approximately 235 °C, the mass percentage decreases until it reaches a constant weight. Above 235 °C, the molecular structure of plant polysaccharides undergoes complete decomposition into smaller molecules or volatilization into gaseous substances. The remaining substance gradually undergoes carbonization and subsequent mass loss. In summary, plant polysaccharides demonstrate favorable temperature resistance at lower temperatures (below around 150 °C), while substantial decomposition or evaporation becomes evident at higher temperatures (above 235 °C).

3.2. Performance Evaluations

3.2.1. Rheological Properties Tests

The rheological performance test data in

Table 1. Effect of XOS on the Rheological Properties of base-mud.

XOS	AV mPa·s	PV mPa·s	YP mPa·s	YP/PV
0%	14.50	9.50	5.00	0.526
0.5%	20.60	14.60	6.00	0.411
1.0%	26.05	17.60	8.45	0.480
3.0%	50.60	29.40	21.20	0.721
5.0%	80.25	35.90	44.35	1.235
0% (150 °C)	13	7.9	5.1	0.646
3.0% (150 °C)	25.5	20.8	4.7	0.226

demonstrate that with an increasing concentration of XOS, the viscosity (AV) and plastic viscosity (PV) of the drilling fluid base-mud progressively rise. At XOS concentrations of 3.0% and 5.0%, AV and PV exhibited substantial increments, reaching 50.6 mPa·s and 80.25 mPa·s correspondingly. This phenomenon arises from numerous hydroxyl functional groups within the molecular structure of XOS. These groups facilitate hydrogen bonding with water molecules and other constituents within the drilling fluid, consequently enhancing the base-mud’s viscosity and viscoelasticity. Under low concentrations, the molecular configuration of XOS has the potential to establish hydrogen bonds with water molecules. This interaction aids in forming an organized hydrated shell around the water molecules within the drilling fluid, consequently amplifying the viscosity of the WBFs. With the elevation of XOS concentration, more hydrogen bonds may develop among its molecules. This occurrence results in heightened intermolecular forces, subsequently intensifying the base-mud’s viscosity and viscoelasticity. Furthermore, the molecular constitution of XOS encompasses hydrophobic components. These components can engage with particle surfaces, including clay particles, fostering the creation of a thin film or adsorption layer that retards the aggregation and accumulation of clay particles, effectively curbing the pace at which plastic viscosity escalates.

3.2.2. Filtration Characteristics Tests

As shown in Figure 3, the filtration loss gradually decreases as the XOS dosage increases from 0.5% to 5.0%. The process by which XOS reduces the filtration of WBFs encompasses its molecular structure and aggregation tendencies. This process establishes a stable lubricating layer or membrane at the liquid-air interface, thus diminishing the liquid’s penetration rate. Concurrently, temperature influences the dispensability, viscosity of the base-mud, and fluidity of the liquid phase containing XOS. Consequently, this impact influences the extent to which XOS enhances the reduction in filtration loss, particularly under elevated temperatures, where its influence could be more pronounced, contributing to reducing filtration and enhancing lubrication performance.

3.2.3. Lubrication Performance Tests

Analysis of the data in

Table 2. Effect of XOS on Lubrication Performance of Base-mud (25 °C).

Formula	Friction Coefficient	Reduction Rate of Friction Coefficient/%
Base-mud	0.9030	/
Base-mud + 0.2%XOS	0.8436	6.58%
Base-mud + 0.5%XOS	0.5539	38.66%
Base-mud + 1.0%XOS	0.3336	63.06%
Base-mud + 3.0%XOS	0.3309	63.36%
Base-mud + 5.0%XOS	0.3226	64.27%

and

Table 3. The Effect of XOS on Lubrication Performance of Base-mud at High-temperature.

Aging Temperature/°C	Formula	Friction Coefficient	Reduction Rate of Friction Coefficient/%
25	4.0% base-mud	0.9030	63.06
	4.0% base-mud + 1.0% XOS	0.3336
90	4.0% base-mud	0.4560	66.21
	4.0% base-mud + 1.0% XOS	0.1541
120	4.0% base-mud	0.5234	64.81
	4.0% base-mud + 1.0% XOS	0.1842
150	4.0% base-mud	0.5357	64.42
	4.0% base-mud + 1.0% XOS	0.1906

reveals a noteworthy trend: the friction coefficient experiences a notable reduction across the temperature range of 25~150 °C after the incorporation of 1.0% XOS. Notably, XOS continues to enhance lubrication performance even under high-temperature conditions. XOS belongs to the class of glycans and boasts a distinctive molecular configuration. Upon introduction to the base-mud of the drilling fluid, XOS may instigate the development of an adherent film at the liquid’s interface. This resultant film facilitates the formation of a lubricating stratum amidst adjacent contacting surfaces. Consequently, the film diminishes relative motion between the lubricated stratum and the drill bit or wellbore, thus effectively curbing frictional forces at the contact interface. Furthermore, the lubricating layer established by agaric polysaccharides can infiltrate minuscule pores or uneven contours within the base-mud of the drilling fluid. This infiltration contributes to surface leveling, thereby mitigating inter-surface friction. The enhancement of lubrication performance in WBFs through XOS arises from its multifaceted contributions, including establishing a liquid-surface lubricating stratum, facilitation of intermolecular interactions, reduction in contact area, and attenuating surface roughness.

3.2.4. Inhibition Performance Tests

The rolling recovery rate experiment serves as a means to assess the suppressive efficacy of additives against the hydration and dispersion of drilling cuttings in elevated-temperature settings. We employed a series of continuous rolling recovery experiments to appraise the inhibitory capacity of XOS. Illustrated in Figure 4, XOS, when employed as an additive, effectively mitigates clay’s hydration and dispersion tendencies. Notably, its indoor testing performance surpasses Potassium chloride and polyamine. The underlying mechanism lies in the ability of XOS, functioning as an additive, to generate a lubricating layer at the interface of clay particles and drilling chips. This layer enhances particle-liquid interactions while augmenting the viscosity of the base-mud. These combined effects effectively hinder the hydration and dispersion processes of clay. Analysis of indoor experimental outcomes indicates that XOS exerts a more pronounced influence within high-temperature environments. This heightened influence can be attributed to its potential to further facilitate interaction and dispersion between XOS and other constituents within the base-mud.

3.3. Environmental Performance Tests

The chemical, biodegradability, and biological toxicity of XOS added to drilling fluid base-mud were tested. The experimental results are shown in

Table 4. Environmental Performance Tests of XOS.

Items	Measured Value	Reference Range
EC50 (mg/L)	55,000	≥30,000
COD (mg/L)	78	60−100
BOD5 (mg/L)	18.5	≤20
BOD5: COD (%)	23.7	≥10
LC50 (mg/L)	50,000	≥30,000

.

The subsequent experimental results stem from environmental performance assessments encompassing chemical toxicity, biodegradability, and biological toxicity of XOS integrated into the drilling fluid base-mud. In relation to EC₅₀ values, XOS demonstrates a relatively elevated figure, signifying diminished toxicity towards aquatic organisms under higher concentrations and exhibiting favorable environmental compatibility. The COD value elucidates the limited imposition of chemical oxygen demand by XOS upon aquatic environments. The BOD₅ value highlights the commendable biodegradability of XOS within aqueous settings. The LC₅₀ value underscores the attribute of low toxicity associated with XOS. Collectively, XOS has yielded promising outcomes in environmental performance evaluation, showcasing low toxicity, commendable biodegradability, and heightened tolerance towards aquatic organisms which establishes XOS as a prospective option for ecological supplementation.

3.4. Mechanism Analysis

3.4.1. Micromorphology Analysis

As shown in Figure 5, we can see that XOS, as an additive, can improve the micromorphology of mud cake in WBFs under both room-temperature and high-temperature conditions. Compared with Figure 5a,b, the base-mud’s clay particles aggregate at 25 °C, resulting in an uneven particle size distribution that gives rise to a relatively coarse mud cake surface. However, upon the incorporation of 3.0% XOS, notable alterations were observed in the morphogenesis of clay particles on the mud cake surface, rendering the surface considerably smoother. Compared with Figure 5c,d, the base-mud’s mud cake surface could exhibit greater roughness in high-temperature conditions, leading to heightened adhesion forces among clay particles. Nonetheless, with the introduction of 3.0% XOS, a sleek surface featuring clay particle smoothness remains discernible on the mud cake surface, even in high-temperature conditions. Overall, experimental outcomes underscore the capacity of XOS as an additive to enhance the micromorphology of mud cakes within WBFs, encompassing both room and high-temperature scenarios. The interaction of XOS with clay particles, creating a lubricating layer or hydration film, potentially mitigates particle adhesion. Consequently, the mud cake surface achieves enhanced smoothness. These findings align with outcomes from preceding rolling recovery experiments, affirming the substantial enhancement conferred by XOS as an additive upon the lubrication efficacy and particle dispersion within drilling fluid.

3.4.2. Particle Size Distribution Tests

As shown in Figure 6, the augmentation of XOS addition yields pronounced alterations in the particle size distribution of clay particles. Following the incorporation of XOS, the distribution of clay particle sizes becomes notably more uniform. Functioning as a polysaccharide, XOS can generate a stable hydration film within WBFs. This hydration film potentially envelops the surfaces of clay particles, thereby attenuating inter-particle interactions. Owing to these hydration membranes, clay particles exhibit heightened suspension stability and diminished propensity for aggregation. Furthermore, the molecular configuration of XOS could interact with specific chemical functional groups residing on the clay particle surface, consequently inducing alterations in the particle’s exterior. This surface chemical reaction might render the clay particle surfaces smoother and diminish particle-to-particle adhesion. Consequently, it can impact both particle aggregation and particle size distribution.

4. Conclusions

This study introduces a novel and eco-friendly approach for the production of Xylooligosaccharides (XOS) and conducts a comprehensive investigation into their application mechanism within Water-Based Drilling Fluids (WBFs). The study’s findings, derived from an analysis of XOS’s unique structural attributes and its impact on WBF performance, yield several significant conclusions:

(1) XOS serves as a highly effective, eco-friendly additive that substantially enhances the overall performance of WBFs. The addition of an optimal quantity of XOS to WBF formulations results in pronounced improvements in several key aspects of drilling fluid behavior. These enhancements include a significant increase in drilling fluid viscosity, a remarkable reduction in filtration loss, and notable improvements in lubrication and inhibition efficacy during drilling operations.

(2) In high-temperature drilling environments, XOS plays a crucial role in forming a lubricating layer or hydrated film, effectively mitigating the interaction between clay particles. This, in turn, leads to a notable improvement in clay inhibition capacity and the lubrication performance of shale. Additionally, XOS demonstrates its capability to achieve a uniform distribution of clay particles throughout the WBF, further contributing to its effectiveness.

These findings collectively underscore the value of XOS as an eco-friendly and sustainable solution for enhancing the performance of WBFs in drilling applications. The study’s innovative approach to XOS production and its systematic assessment of its impact within drilling fluids provide valuable insights for the oil and gas industry, with implications for improved drilling fluid formulations and practices. Further research and development in this area hold the potential to yield even more refined XOS variants with enhanced performance attributes, further advancing the field of sustainable drilling fluid technology.