Shale Inhibitor Research Articles

Synthesis and properties of a novel ionic liquid copolymer shale inhibitor

AbstractAs oil reserves in shallow wells continue to deplete, the drilling industry must shift its focus toward extracting oil from deeper and more complex formations. Water‐based drilling fluid inhibitors are currently limited in their ability to withstand high temperatures. In the current work, for the first time, the application of 1‐vinyl‐3‐ethylimidazolium bromide salt‐allyl alcohol polyoxyethylene ether‐2‐acrylamide‐2‐methylpropanesulfonic acid (PIAA) as the shale inhibitor is reported. The incorporation of ionic liquids has made PIAA promising to be an effective shale inhibitor for high‐temperature‐tolerant water‐based drilling fluids. The high‐temperature resistance (300°C) of PIAA was verified through thermogravimetric test. Through mud ball, shale rolling recovery, and linear swelling experiments, we found that PIAA yielded the lowest swelling rate (27.3%) in the 24‐h linear swelling rate test, as compared to HMA‐15 (46.1%) and FA‐367 (31.2%). This confirmed the superior corrosion inhibition performance of PIAA. In addition, we investigated the inhibition mechanism using Zeta potential and other tests. Bentonite inhibition can be achieved through the coating of bentonite particles by PIAA, which effectively plugs shale pores, neutralizes negative charges on the surface of bentonite particles, and adsorbs them onto particle surfaces. Overall, PIAA has excellent high‐temperature resistance and inhibition properties.

Investigation on the interlayer intercalation inhibition mechanism of polyamines with different adsorption functional groups on montmorillonite: Experiment and density functional theory simulation

Water-based drilling fluids (WBDFs) are gaining popularity as they exhibit comparable inhibitory properties to oil-based drilling fluids, making them an ideal choice for drilling horizontal shale gas wells. This study focuses on understanding the intercalation inhibition mechanism of various inhibitors, namely 1,6-hexane diamine (HDA), N,N′-dimethyl-1,6-hexane diamine (DHDA), N,N,N′,N′-tetramethyl-1,6-hexane diamine (THDA), and hexamethyl diammonium chloride (HDC), each possessing different functional groups. The interaction and performance of these inhibitors on the swelling of montmorillonite (Mt) were investigated through a combination of experimental techniques containing X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, and density functional theory simulation. Results reveal that at a low dosage of 0.7 CEC (cation exchange capacity), the wet Mt-HAD, Mt-DHDA, Mt-THDA, and Mt-HDC compounds exhibit basal spacing of 1.30 nm, 1.33 nm, 1.34 nm, and 1.42 nm, respectively. The basal spacing remains unchanged when a higher dosage of 3.0 CEC is added. Comparatively, the basal spacing of dry Mt-inhibitor compounds is slightly reduced. This suggests that the addition of a smaller amount of inhibitor also demonstrates excellent inhibitory performance. Thermogravimetric and differential thermogravimetric analysis of Mt-inhibitor hybrid structure indicate that Mt-HDA compounds exhibit both low and high-temperature peaks, while Mt-DHDA, Mt-THDA, and Mt-HDC compounds only show a low-temperature peak. This indicates that while HDA partially inhibits surface hydration of Mt, DHDA, THDA, and HDC effectively inhibits surface hydration of Mt. Additionally, the microscopic mechanism of inhibitor adsorption on the Mt was explored using density functional theory simulation. HDC adsorption energy on Mt significantly increased relative to DHDA, THDA, and HDA. This indicates that inhibitors featuring quaternary ammonium functional groups exhibited superior inhibitory performance. As a result, inhibitors with quaternary ammonium functional groups hold promise as potential shale inhibitors for WBDFs.

Utilization of mesoporous nano-silica as high-temperature water-based drilling fluids additive: Insights into the fluid loss reduction and shale stabilization potential

Optimally performing drilling fluids play a vital role in drilling operations. The demand for thermally stable drilling fluid in the oil and gas sector necessitates using advanced additives to create suitable formulations. This research study introduces the novel application of Mesoporous Nano-Silica (MNS) to enhance water-based drilling fluid's inhibitive, rheological, and fluid loss characteristics. MNS was synthesized by the sol-gel technique with Cetyltrimethylammonium Bromide (CTAB) for generating the pores. The hydrodynamic particle size of the synthesized MNS was 134.47 nm with a stable zeta potential of −32.2 meV. Brunauer-Emmett-Teller (BET) analyzer estimated the specific surface area to be 626 m2/g and the pore volume to be 0.3415 cm3/g. A comparative analysis of the drilling fluid properties is presented in which MNS was added to the fixed base formulation at varied concentrations (0.05, 0.1, 0.2, 0.5, and 1 wt%). Samples were subjected to hot rolling at 180 °C temperatures at 100 psi pressure for 16 h, evaluating the influence of thermal aging on the properties of the drilling fluid. The viscometric investigation was performed at 25 and 70 °C while the inhibitive properties were checked via shale recovery test and capillary suction timer. The filtration properties were examined at 100 psi and 500 psi pressure at 150 °C. The experimental findings reveal that MNS can substantially improve the thermal properties of water-based drilling fluids, maintaining rheological characteristics and drastically reducing fluid loss while imparting some inhibitive properties. Interestingly, after hot rolling the plastic viscosity of MNS-infused mud was 77% better than that of the base mud. Incorporating macro-sized particles and MNS nanoparticles into water-based drilling fluids can enhance its rheological properties, reduce filtrate loss, and improve shale inhibition characteristics which may be attributed to either the size effect or the synergistic influence of materials. Therefore, including MNS as a high-performance additive may contribute to advancing drilling operations in the petroleum industry, offering valuable insights for optimizing drilling fluid formulations.

Preparation and Application of New Polyhydroxy Ammonium Shale Hydration Inhibitor

Wellbore instability caused by the hydration of shale formations during drilling is a major problem in drilling engineering. In this paper, the shale inhibition performance of polyhydroxy-alkanolamine was evaluated using an anti-swelling test, linear swelling test, wash-durable test and montmorillonite hydration and dispersion experiment. Additionally, the shale inhibition mechanism of polyhydroxy-alkanolamine was studied via Fourier transform infrared spectroscopy (FTIR), particle size, zeta potential, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results show that the use of polyhydroxy-alkanolamine (EGP-2) could result in a relatively lower linear swelling rate of montmorillonite, and the linear swelling rate of 0.3% EGP-2 is 26.98%, which is stronger than that of 4% KCl. The anti-swelling rate of 0.3% EGP-2 is 43.54%, and the shrinkage–swelling rate of 0.3% EGP-2 is 34.62%. The study on the inhibition mechanism revealed that EGP-2 can permeate and adsorb on the surface of montmorillonite. The rolling recovery rate of easily hydrated shale was as high as 79.36%, which greatly reduces the dispersion ability of water to easily hydrated shale. The results of this study can be used to maintain the stability of a wellbore, which is conducive to related research.

Synthesis of a novel polysiloxane as an inhibitor in water-based drilling fluids and an assessment of the inhibition mechanism

In oil and gas well engineering, shale wellbore stability poses significant challenges. Developing shale inhibitors with high inhibition and resistance to elevated temperatures is crucial to address wellbore stability in deep wells. In this study, an amphoteric polysiloxane known as SC-POTD was synthesized as a heat-resistant shale inhibitor for water-based drilling fluid. The inhibition properties were evaluated using linear swelling, rolling recovery, and rheological tests, and the results were compared with the properties of potassium chloride and commercial polyamines. Various analysis methods were conducted to understand the interaction mechanism between the clay particles and polymer molecules, including X-ray diffraction test, Zeta potential determination, particle size analysis, contact angle measurement, and scanning electron microscope observation. SC-POTD with an amphoteric structure can effectively adsorb on the clay surface through electrostatic force, compressing the electric double layer of clay and forming a hydrophobic layer. Furthermore, SC-POTD can embed in the crystal interlayer, exchange cations and discharge interlayer water, effectively inhibiting hydration. With the flexibility of the Si-O backbone and the small steric hindrance of methyl side groups, SC-POTD may have a better affinity with bentonite containing siloxane tetrahedrons, and cooperate with the quaternary ammonium group to enhance clay interlayer interaction. In addition, the temperature resistance of SC-POTD can be improved by the siloxane backbone with larger bond energy. The results indicated that modified polysiloxane may find a promising application as heat-resistant drilling fluid additives.

Revolutionizing shale drilling with potassium chloride-based natural deep eutectic solvent as an additive

Shale instability is a significant problem, accounting for approximately 70% of wellbore challenges during drilling operations. To address this issue, shale inhibitors are commonly added to drilling mud to stabilize the encountered shale formations. Ionic liquids and deep eutectic solvents have been recognized as effective shale inhibitors due to their environmental friendliness and effectiveness. However, despite their advantages, these solutions still lack full environmental sustainability, leading researchers to explore more natural alternatives like Natural Deep Eutectic Solvents (NADES). This study focuses on the synthesis and application of a NADES composed of Potassium Chloride (KCl) and glycerine, aiming to enhance the environmental profile and efficacy of shale inhibitors. The NADES was prepared with a 1:8 molar ratio at a temperature of 60 °C. Characterization analyses, including Fourier Transform Infrared and Thermogravimetric Analysis, confirmed the formation of bonds between –(OH) and Cl− and demonstrated the NADES's thermal stability up to 200 °C. Incorporating 3% NADES into water-based mud, prepared following API 13B-1 standards, resulted in significant improvements in mud rheology. Specifically, the addition of 3% NADES reduced filtrate volume by 14.2% and mud cake thickness by 19.2%. Furthermore, the 3% NADES exhibited remarkable inhibition of clay swelling by 69.23% and demonstrated a shale recovery rate of 58%. When compared with 3% KCl and 3% 1-ethyl-3-methylimidazolium chloride (EMIM-Cl), the NADES-based mud outperformed both in terms of efficacy. These findings were further supported by additional analyses, including d-spacing measurements (XRD), Zeta Potential, Surface tension, and Field Emission Scanning Electron Microscopy. Additionally, the rheological behavior of the NADES-based mud aligned with the Yield Power Law at both 25 °C and 100 °C. The study's findings contribute to the advancement of greener drilling practices and highlight the applicability of KCl-based NADES as a potential drilling fluid additive.

Improving the performance of a polyamine shale inhibitor by introducing a hydrophobic group in oil and gas development

Wellbore instability in complex shale formations is a major technical problem that threatens drilling safety and efficiency. In this paper, a hydrophobic cationic polyamine shale inhibitor (HCPA) was prepared by introducing a hydrophobic group in the molecular structure of an amine-based shale inhibitor having a branched structure. The shale inhibition performance of HCPA and the amine-based shale inhibitor without the hydrophobic group (CPA) was investigated. The hydration inhibition mechanism of HCPA was studied by experiments of zeta potential, particle size, contact angle, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), etc. The evaluation results show that HCPA had a better performance than CPA in terms of inhibition of hydration swelling, hydration dispersion and mud making, which indicates that the hydrophobic group is beneficial to improve the inhibition ability of the amine-based shale inhibitor. The mechanism study shows that there is no hydrogen bond between HCPA and clay. The adsorption on the clay surface is mainly driven by electrostatic interaction, which reduces the repulsion of the electric double layer and thus inhibits the osmotic swelling of clay. HCPA could increase the water contact angle of the rock from 36.6° to 133° at a concentration 0.5%, beneficial to reduce surface free energy. The bentonite modified by HCPA had a lower weight loss of at 200 °C than bentonite modified by CPA according to TGA test, and the interlayer spacing of HCPA-modified bentonite was reduced compared with that of the unmodified bentonite, indicating that the ability of bentonite to adsorb water molecules is reduced after the introduction of hydrophobic groups, beneficial to inhibit the crystalline swelling of clays. In addition, HCPA can reduce the imbibition capacity of rocks by reducing the surface tension of water. Therefore, the concept of introducing hydrophobic groups in the molecular structure proposed herein could provide an avenue to develop high-performance shale inhibitors.

Performance evaluation of different cationic surfactants as anti-swelling agents for shale formations

In this study, three different novel cationic surfactants decyl-trimethyl-ammonium bromide (S1), Octyl-trimethyl-ammonium bromide (S2), hexyl-trimethyl-ammonium bromide (S3) were used to formulate water-based drilling formulations to comprehend the interactions between drilling fluids components and with wellbore formations. The modified drilling formulations were prepared by incorporating novel surfactants in the base mud along with other additives such as bentonite, PAL-C, xanthan gum, and barite. The effect of the surfactant's chemical structure was assessed by rheology and filtration experiments, and colloidal dispersion stability was determined by particle size distribution analysis and sedimentation tests. The shale swelling inhibition characteristics of surfactant-based formulations were accessed by hot rolling dispersion tests, linear swelling rates, and capillary suction time tests. The performance of surfactant-based formulations for shale swelling inhibition was compared with KCl-based and conventionally used base mud formulations. The surface wettability of shale in the presence of different formulations was assessed by a high-resolution optical tensiometer. Shale inhibition properties of surfactant-based formulations depict that shale dispersion recovery increased to 98% for BS1 formulation compared to all other used formulations. Linear swelling of shale pellet show that the swelling rate of BS1 formulation was only 13% compared to all other formulations. The contact angle experiments showed that the BS1 formulation increased the contact angle of a water droplet and reduced the wettability of drilling fluids. The experimental results showed that S1 surfactant has enhanced shale inhibition characteristics compared to other surfactants and conventionally used shale inhibitors.

Epsom Salt-Based Natural Deep Eutectic Solvent as a Drilling Fluid Additive: A Game-Changer for Shale Swelling Inhibition.

Shale rock swelling poses a significant challenge during drilling a well, leading to issues related to wellbore instability. Water-based mud with specific shale inhibitors is preferred over oil-based drilling mud due to its lower environmental impact. Recently, ionic liquids (ILs) have emerged as potential shale inhibitors due to their adjustable properties and strong electrostatic attraction. However, research has shown that the most commonly used class of ILs (imidazolium) in drilling mud are toxic, non-biodegradable, and expensive. Deep Eutectic Solvents (DESs), the fourth generation of ionic liquids, have been proposed as a cheaper and non-toxic alternative to ILs. However, ammonium salt-based DESs are not truly environmentally friendly. This research explores the utilization of Natural Deep Eutectic Solvent (NADES) based on Epsom salt (a naturally occurring salt) and glycerine as a drilling fluid additive. The drilling mud is prepared according to API 13B-1 standards. Various concentrations of NADES-based mud are tested for yield point, plastic viscosity, and filtration properties for both aged and non-aged samples. The linear swell meter is used to determine the percentage swelling of the NADES-based mud, and the results are compared with the swelling caused by KCl- and EMIM-Cl-based mud. FTIR analysis is conducted to understand the interaction between NADES and clay, while surface tension, d-spacing (XRD), and zeta potential are measured to comprehend the mechanism of swelling inhibition by NADES. The findings reveal that NADES improves the yield point and plastic viscosity of the mud, resulting in a 26% reduction in mudcake thickness and a 30.1% decrease in filtrate volume at a concentration of 1%. NADES achieves a significant 49.14% inhibition of swelling at the optimal concentration of 1%, attributed to its ability to modify surface activity, zeta potential of clay surfaces, and d-spacing of clay layers. Consequently, NADES emerges as a non-toxic, cost-effective, and efficient shale inhibitor that can replace ILs and DESs.

Eco-Friendly Drilling Fluid: Calcium Chloride-Based Natural Deep Eutectic Solvent (NADES) as an All-Rounder Additive

Designing an effective drilling mud is a critical aspect of the drilling process. A well-designed drilling mud should not only provide efficient mud hydraulics but also fulfill three important functions: enhancing mud rheology, inhibiting hydrate formation in deepwater drilling, and suppressing shale swelling when drilling through shale formations. Achieving these functions often requires the use of various additives, but these additives are often expensive, non-biodegradable, and have significant environmental impacts. To address these concerns, researchers have explored the potential applications of ionic liquids and deep eutectic solvents in drilling mud design, which have shown promising results. However, an even more environmentally friendly alternative has emerged in the form of natural deep eutectic solvents (NADES). This research focuses on an in-house-prepared NADES based on calcium chloride and glycerine, with a ratio of 1:4, prepared at 60 °C, and utilizes it as a drilling mud additive following the API 13 B-1 standards and checks its candidacy as a rheology modifier, hydrates, and shale inhibitor. The findings of the study demonstrate that the NADES-based mud significantly improves the overall yield point to plastic viscosity ratio (YP/PV) of the mud, provides good gel strength, and inhibits hydrate formation by up to 80%. Additionally, it has shown an impressive 62.8% inhibition of shale swelling while allowing for 84.1% improved shale recovery. Moreover, the NADES-based mud exhibits a 28% and 25% reduction in mud filtrate and mud cake thickness, respectively, which is further supported by the results of XRD, zeta potential, and surface tension. Based on these positive outcomes, the calcium chloride–glycerine NADES-based mud is recommended as a versatile drilling mud additive suitable for various industrial applications. Furthermore, it presents a more environmentally friendly option compared to traditional additives, addressing concerns about cost, biodegradability, and environmental impact in the drilling process for an ultimate global impact.

Hydration inhibition and physical plugging to enhance shale stability using zwitterionic polymer/nano-silica composite

In order to enhance shale stability during drilling operations, efficient shale stabilizers in water-based drilling fluids become an urgent demand. In this work, a novel shale stabilizer (ZPS) was synthesized by grafting zwitterionic polymer onto nano-silica through two steps. The particle size of ZPS ranged from 80 to 355 nm, exhibiting a regular spherical shape. The hydration inhibition property was determined by Na-bentonite (Na-BT) immersion, linear swelling and hot-rolling dispersion test. ZPS behaved superior inhibition ability compared with commonly used shale inhibitors in all tests. The plugging performance was evaluated by pressure penetration test. Results indicated that ZPS could slow down pressure penetration rate and decrease shale permeability, which displayed better plugging ability than SiO2. The mechanism study showed that the cationic groups in ZPS could be tightly adsorbed on the clay surface through electrostatic attraction to inhibit clay hydration. In addition, ZPS could enter into the pores and fractures of shale to form a plugging layer with weak water affinity, resulting in excellent plugging performance. The dual roles of ZPS in hydration inhibition and physical plugging demonstrated its potential as an efficient shale stabilizer.

Application of Novel Magnetic Surfactant-Based Drilling Fluids for Clay Swelling Inhibition

Water-based drilling fluids are widely employed in the oilfield industry for the efficient and smooth drilling of wellbore reservoirs. In this study, a novel drilling formulation was prepared by mixing a magnetic surfactant in the base mud formulation. Several drilling fluid tests were conducted, which include steady shear and dynamic rheology, filtration, clay sedimentation, clay swelling, and particle size distribution analysis. Different analytical techniques─XRD, FTIR, and TGA analyses─were performed to study the interactions of magnetic surfactant with the clay platelets. The experimental results of the surfactant-modified formulations were compared to the base mud formulation. Thermal gravimetric analysis of the surfactant-modified mud showed improved thermal stability compared to the base mud. FTIR analysis results of the base mud and surfactant-modified mud were compared. In the steady shear rheology experiments, the flow curves of the base mud and surfactant-modified mud showed that the addition of surfactant in the base mud affects the shear stress of formulation. The shear stress data of rheology was fitted to the Herschel–Bulkley model, and model parameters trends were assessed with and without the addition of surfactant in the base mud. Shale inhibition tests showed that the incorporation of magnetic surfactant minimized the clay hydration of swelling, thus proving a superior shale inhibitor. The particle size analysis showed that the average particle size of clay particles increased with the increasing concentration of the magnetic surfactant. The linear swelling analysis of clay showed that the rate of swelling was 90% in the surfactant-modified mud as compared to the swelling rate in deionized water. According to the zeta potential, the combination of surfactants significantly affects the electrokinetic behavior of dispersion. Further, the XRD proved that the interlayer spacing of clay increasing while interacting with magnetic surfactant molecules indicates the ability of magnetic surfactant as a shale swelling and hydration inhibitor for water-based drilling formulations.

Synthesis of polyacrylic-melamine grafted graphene as efficient inhibitor for shale stabilization in water-based drilling fluid

The penetration of water-based drilling mud into the formation in the drilling is a serious issue that causes wellbore instability. Here, a polymer-grafted graphene nanosheets (Gr-AM) was prepared as an inhibitor in water-based drilling mud. The polymer was prepared via free radical polymerization using precursors of acrylic acid, melamine, and graphene. Fourier transform infrared spectroscope (FT-IR) and transmission electron microscopy (TEM) were utilized to characterize the prepared polymer. Thermogravimetric analysis (TGA) was employed to evaluate the material's thermal stability. Several inhibition tests were carried out such as shale recovery test, anti-swelling parameter, and immersion analysis. The results showed that the Gr-AM could be stable up to 240 °C. The low concentration of Gr-AM achieved good inhibition performance compared to AM and KCl as common inhibitors. The results of this work offer some technical ideas for developing of high-performance shale inhibitors..

Hydrophobically modified low molecular weight polymers as high temperature resistant shale inhibitor

With the exploration and development of deep oil and gas, an efficient shale inhibitor resistant to high temperatures is critical for wellbore stability during drilling. In this paper, a hydrophobically modified low molecular weight polymer (SDY) is studied to maintain wellbore stability at high temperatures during drilling. The inhibition performance of SDY was investigated using linear swelling experiments and rolling recovery experiments at different temperatures. The experimental results showed that SDY had good inhibition performance. At 150 °C, the expansion rate was 61.69 % for 1 % SDY and 175.51 % in water. And the rolling recovery of shale rock chips was 87.53 % for 1 % SDY and 18.92 % in water. Compared with water, it can reduce the hydration swelling rate of bentonite rock mold by 57 % and improve the recovery rate of shale rock chips by 3.37 times at 150 °C. The inhibition mechanism of SDY was analyzed by zeta potential, particle size distribution, contact angle, self-absorbing water, X-ray diffraction and scanning electron microscopy experiments. The good inhibition performance of SDY at high temperatures may be attributed to three aspects. First of all, SDY molecules can neutralize the negative charge on the shale surface by electrostatic effect, and reduce the repulsive force between shales to inhibit the hydration dispersion of shales. Second, SDY can still adsorb on the shale surface at high temperatures to form a hydrophobic film and change the wettability of the shale surface. This increases the adsorption resistance of water molecules on the shale surface thereby inhibiting shale surface hydration. Third, SDY molecules can insert between the layers of bentonite sheets to bind the adjacent clay layers together, effectively inhibiting the permeable hydration of shale. This study provides an approach for addressing wellbore stability in deep wells with higher temperature.

Probing the physicochemical interactions between thermo-thickening polymers and clay fluids for improve rheological performance

The field of thermo-thickening polymer interacting with clay has long been shrouded in mystery and ambiguity. Despite numerous studies and investigations, the complex interactions, underlying mechanism and binding forces remain elusive, imposing further exploration and elucidation. In this study, three thermo-thickening polymers such as poly(acrylamide methylpropane sulfonic acid-co-N-vinylcaprolactam) (PNV), poly(acrylamide methylpropane sulfonic acid-co-N,N-dimethylacrylamide) (PDM), and poly(acrylamide methylpropane sulfonic acid-co-N-isopropylacrylamide) (PNP) with clay fluids (CFs) were investigated to gain deeper understanding of the underlying physicochemical interactions. Techniques such as Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), and elemental analysis (EA) elucidated the structural properties, whereas turbidimetry and rheometric analysis elucidated the temperature-induced phase transitions. The interactions between the different polymer side chains and clay double-sheets were investigated through isothermal adsorption testing, probing chemisorption and hydrogen bonding tuned the chemical properties, whereas electrostatic forces (ionic/van der Waals) bind the physical properties as demonstrated by Zeta (ζ) potential, XRD, high-resolution spectroscopy (XPS), and scanning electron microscopy (SEM) imaging. The addition of 0.2–1.5 wt% of the polymers induced significant effect on the rheological properties of CFs, with increase in low shear viscosity and plastic viscosity, attributed to the formation of gel-like structures at high temperatures. PNV/Clay (NVBF)-modified fluid demonstrated exceptional fluid thickening and suspension behaviors compared to linear PDM/Clay (DMBF) and PNP/Clay (NPBF)-modified fluids. In addition, NVBF exhibited significantly higher adsorption energies and basal spacings, along with more crystalline patterns suited to embed clay particles. Overall, the synergistic effect of the different polymer side chains with clay particles provides valuable insights on the mechanistic and enhancement of rheological properties of CFs effective as shale inhibition, viscosifier and wellbore stabilization.

Bead and necklace-like silica-based hybrid materials for controlling montmorillonite dispersion filtration

Taking the advantage of well dispersing ability and unique pore plugging capacity, nanomaterials have been extensively used as filtration control additives in water-based drilling fluids (WBDFs). However, nanomaterials are seldom robust when exposed to high temperature and salinity which restricts their applications. Herein, we synthesize two inorganic/organic hybrid nanomaterials using silica as the core and grafted with zwitterionic polymer on the surface (ZSHNM-1 and ZSHNM-2), and conduct in-depth research on their filtration performance. ZSHNM exhibits bead- and necklace-like structures, adsorbs onto and promotes the homogenous dispersion of montmorillonite irrespective of the presence of salt, and facilitates the formation of filter cake with remarkably low permeability, according to experimental results and DFT simulation results. Notably, ZSHNM-2 has significantly stronger thermal resistance up to 250 °C, salt tolerance as high as 11 wt%, which is expected to use in filed applications of ultra-deep wells. It is attributed to the more appropriate particles size distribution and longer polymer tails, efficiently plugging the pores. In addition, these nanomaterials had high polyamine rejection, whereas had little influence on KCl, which should be paid attention to selecting shale inhibitors. This study can be a guide to technically related areas where nanomaterials are used extensively.

A Novel Ascorbic Acid Based Natural Deep Eutectic Solvent as a Drilling Mud Additive for Shale Stabilization

During drilling, almost 70% of wellbore instability issues result from the encountering of shale formations. Various additives such as salts, silicates, and polymers are used in water-based mud to enhance its shale-inhibition capability; however, such additives have certain limitations. Lately, ionic liquids and deep eutectic solvents (DES) have been used by various research groups as shale inhibitors in drilling fluid due to their biodegradability and efficacy. However, their popularity faded when a natural derivative of DES, i.e., Natural Deep Eutectic solvent (NADES), came into the picture. This research utilizes the in-house-prepared Ascorbic acid and Glycerine (AA:Gly)-based NADES as a drilling fluid additive for shale inhibition and compares its efficacy with counterpart inhibitors such as KCl, imidazolium-based ionic liquid, and Choline Chloride-based DES. The results show that 3% NADES improved the overall Yield point to Plastic viscosity ratio, with a 39.69% decline in mud cake thickness and a 28% decline in the filtrate volume of drilling mud. Along with improved drilling fluid properties, 3% NADES resulted in 77.77% shale inhibition and 87% shale recovery. Surface tension, d-spacing, zeta potential, and FESEM have been conducted to justify and elucidate the inherent mechanism behind the working of NADES as a drilling fluid additive and clay stabilizer. Thus, Ascorbic acid-based NADES is recommended as a potential non-toxic and cheap drilling fluid additive to improve drilling fluid properties and clay stability.

Pore pressure transmission test as measure of shale inhibition performance of nanoparticle additives in water based drilling fluids – A comprehensive review

This paper presents comprehensive review of effect of different nanoparticles such as nanosilica, aluminium nanoparticles (NPs), Magnesium oxide NPs, Zinc oxide NPs, Calcium carbonate NPs, Laponite NPs on pore pressure transmission and discusses its inhibition capability in different shale formations. Shale formations consist of water sensitive clays that react with water and swell. Fluid from water-based drilling fluid (WBDF) invades into shale sections and increases the pore pressure. Therefore, abnormal pore pressure is result of swelling mechanisms of clay that leads to wellbore instability. Pore pressure transmission test (PPT) measures membrane efficiency of shale formations in the oil and gas well drilling operation. Recently, it was reported that addition of nanoparticles in WBDF can plug the shale pores and decrease rate of PPT effectively up to 97%. However, the plugging ability of nanoparticles depends on its size, other additives in the drilling fluid and clay minerals in shale formation etc. This article also analyses nanoparticles performance with conventional shale inhibitors like polymers and clays.

Synthesis of novel hydrophobic nanocomposite-modified silica as efficient shale inhibitor in fuel industry

Highly inhibitive and high-temperature-resistant shale inhibitors are required to be developed as water-based drilling fluids to accomplish the requirements of the drilling process. In this work, silica nanoparticles were grafted with hyperbranched APTMS and FOTS. The modified material and shale were analyzed by several characterizations such as scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) spectroscopy, X-Ray diffractometer (XRD), thermal gravimetric analysis (TGA), and water contact angle (WCA) measurements. The experimental results revealed that the developed material displayed outstanding shale inhibition properties, such as inhibition in the hot rolling recovery test reaching ≈96% compared to 60.40% by KCl standard test. Moreover, the swelling test of Na-Bentonite (Na-Bt) was significantly determined in the presence of a nanocomposite inhibitor accounting for around 86% in comparison to KCl which is ≈56%. This result represented the high effectiveness of the developed material to prevent the expansion of water (hydrophobic property) into the original shale which is significantly greater than KCl commercial inhibitor. This study can be suggested the design of a permanent shale inhibitor for Water-based mud (WBM) in the larger drilling operation.

Evaluations of Polyacrylamide Water-Based Drilling Fluids for Horizontal Drilling in the Shaly Wolfcamp Formation

Summary The Permian Basin, located in southeastern New Mexico and west Texas, is treated as the largest province of oil and gas production in the United States (US). The majority of hydrocarbon production from the Permian Basin is from the Wolfcamp shaly formation. Drilling horizontal and extended reached wells is continuously increasing day after day in the Permian Basin. Oil-based mud (OBM) is used to drill these horizontal wells for enhancing shale inhibition, reducing torque and drag, and supporting thermal stability of mud rheology. Due to environmental regulation for limiting use of OBM, the petroleum industry has tried to develop water-based fluid (WBF) that approaches the performance advantages of OBM. The main objective of this research is to formulate and develop WBF by using polyacrylamide anionic friction reducer (AFR) for drilling the lateral sections of horizontal wells in the shaly Wolfcamp formation. Shale inhibition, barite sagging, lubricity, and thermal stability of the formulated WBF with AFR will be studied to evaluate the developed WBF. Laboratory experiments were conducted to develop and evaluate the performance of the formulated WBF with AFR. The shale inhibition capabilities of the developed WBF with AFR were evaluated by using zeta potential, shale dispersion test, and immersion test. The results prove the capability of the formulated WBF with AFR to prevent both shale swelling and shale dispersion. AFR limits water penetrations to shale through encapsulation. The mixing procedures of AFR with WBF affect both the thermal stability of mud rheology and shale inhibition. Adding AFR to WBF helps to suspend weighting materials and mitigate barite sag. Besides, AFR decreases torque and drag by decreasing the coefficient of friction (COF). Furthermore, AFR supports enhanced stability of mud rheology with time up to 14 days at temperatures up to 180°F. The formulated WBF with AFR can be used for enhancing shale inhibition, supporting thermal and time stability of fluid rheology, improving lubricity, and minimizing barite sagging for drilling shaly Wolfcamp formations. This study presents a promising WBF to replace OBM to drill lateral sections in the Permian Basin.