Properties Of Drilling Fluids Research Articles

Evaluating the maximum drilling length of horizontal geothermal wells utilizing temperature constraints

The geothermal industry faces a significant challenge in exploring and developing resources due to elevated temperatures in downhole environments. Successful drilling in high-temperature geothermal wells requires precise thermal management. This research assesses constraints on horizontal section length and temperature during geothermal horizontal well drilling, aiming to formulate effective wellbore temperature management guidelines.The study utilizes thermal resistance analysis to establish a tailored transient heat transfer model for high-temperature horizontal geothermal well drilling. Parameters such as circulation time, horizontal section length, flow rate, drilling fluid properties, formation thermal conductivity, and drill string thermal conductivity are thoroughly investigated. Treating input parameters as triangular distributions, Monte Carlo simulation techniques conduct sensitivity analysis. Tornado diagrams quantitatively determine key parameter impacts on bottom-hole temperature. The research introduces a procedural framework for geothermal well drilling, aiding engineers in swiftly identifying operational parameter combinations for effective wellbore temperature management. This workflow provides practical guidance for geothermal resource development, ensuring drilling safety in diverse conditions.

The influence of nanoparticle size, concentration, and functionalization on drilling fluid filtration properties

This research investigates the effect of the surface properties of silicon dioxide (SiO2) nanoparticles on the filtration properties of water-based drilling fluid. The nanoparticles were synthesized in-house using a one-step sol-gel method and functionalized into different charges. Different sizes, concentrations, and functionalization of water-based drilling fluid were subjected to standard API and HPHT filtration tests. Regression analysis and ANOVA were carried out to develop a model for future prediction and classify each independent variable's significance. The result shows that the positively charged nanoparticles had better filtration properties, as evidenced by the lower filtrate volume. Functionalization levels had minimal impact on filtration properties, and the effect of concentration was insignificant above 0.4 v/v%. In terms of nanoparticle size, 120 nm showed a more consistent result despite varying concentration and functionalization. In contrast, smaller nanoparticle sizes are more susceptible to changes in concentration and functionalization but could produce the least filtrate volume with the appropriate combination of concentration and functionalization. Filtrate analysis shows that about 25–28 % of the drilling fluid nanoparticles can infiltrate the porous media. Furthermore, this study challenges existing models on the improvement of the filtration properties by using nanoparticles. While previous hypothesis relied on physical bridging mechanism, new evidence from this research suggests that the enhancement is primarily based on the surface properties of the nanoparticles. Specifically, the nanoparticles envelop the barite through monolayer adsorption, reducing the angularity and increasing the reaction sites with water molecules. This inhibits the mobility of the water molecules across the filter cakes, providing a novel understanding of the mechanisms underlying nanoparticle-enhanced filtration properties of drilling fluids. In summary, the filtration properties of water-based drilling fluid with nanoparticles are significantly influenced by the surface properties of the nanoparticles, with positively charged nanoparticles demonstrating superior performance in stable conditions.

Effect of concentration and functional group of cellulose nanocrystals on the rheological and filtration properties of water-based drilling fluids at various temperatures

Effect of concentration and functional group of cellulose nanocrystals on the rheological and filtration properties of water-based drilling fluids at various temperatures

Feasibility study of biodegradable coffee ground waste and watermelon rind as water-based drilling fluid additives

Addressing environmental concerns in extracting and producing hydrocarbon resources requires environmentally friendly water-based drilling fluid (WBDF) additives. These additives not only protect the environment but also offer operational benefits. One of the major challenges of WBDF is fluid loss into the formation and its degradability in high-temperature conditions, which induce cost, formation alteration and environmental pollution. This study explored the feasibility of wasted watermelon rind powder (WRP) and coffee ground waste powder (CGWP) as potential WBDF additives to regulate fluid loss and modify other rheological properties. WRP and CGWP were characterized using Energy Dispersive X-Ray (EDX) and Fourier Transform Infrared Spectroscopy (FTIR) tests. The thermal stability of the proposed additives was confirmed using a thermogravimetric analysis (TGA) test. Several experiments were conducted to investigate the impact of WRP and CGWP with different weight concentrations (wt.%) on the rheological and drilling fluid properties of conventional WBDF. The results show that at 3 wt%, the WRP improved the plastic viscosity by 75% and the CGWP increased the plastic viscosity by 100%. At the same time, the CGWP reduced the gel strength substantially, while WRP increased the gel strength. At an optimum 3 wt%, the CGWP reduced fluid loss by 53%, resulting in the thinnest filter cake thickness. These results demonstrate the potential use of the studied materials as multifunctional additives in drilling operations with WBDF.

Investigating the Effect of Palm Kernel Shell Powder on the Rheological and Filtration Properties of Water Based Mud

During drilling operations, the use of drilling fluid plays a critical role, and over time, there has been considerable interest in enhancing drilling fluid characteristics in order to improve performance, reduce costs, and prevent environmental pollution. Deviating from conventional additives, recent studies have explored the use of alternative materials, as drilling fluid additives. In line with this trend, this study focuses on the laboratory investigation of the rheological and filtration properties of water-based drilling fluid treated with Palm Kernel Shell Powder (PKSP) with high viscosity polyanionic cellulose (PAC HV), used as control. To assess the impact of PKSP in water-based mud, experiments were carried out using concentrations spanning from 0.5g to 2.5g, temperatures of 27°C, 40°C, 60°C, and 80°C, and aging of 24, 48, and 72 hours. From the results the plastic viscosity of mud samples treated with PKSP were temperature dependent and also with increasing aging. The addition of PKSP showed improved performance in terms of reducing the filtrate volume as well as the cake thickness with increasing concentration of the additives, and the concentration that gave the best results across all aging duration was 2.5g. The mud weight and pH of all samples remained relatively constant, with no significant changes observed. However, PAC HV showed better results in all the cases of fluid loss and mud cake thickness. It could be attributed to the soluble contents in the PAC HV which increased the viscosity significantly and thus, kept the solid particles in suspension.

Using Environmentally Friendly Materials to Improve the Properties of the Drilling Fluid

This study presents a significant advancement in addressing the utilization of environmental additives to improve the properties of drilling mud. The current materials added to drilling fluids could cause a harmful effect on the environment and safety of individuals, highlighting the necessity for alternative additives. In this study, the potential use of orange peel powder (OPP) and Sidr leaf powder (SLP) as environmentally friendly additives to drilling fluid is evaluated. Laboratory tests were conducted to identify the impact of OPP and SLP on the drilling fluid properties. Different weights (1-20) % of OPP and SLP were utilized to prepare the drilling fluid. The results demonstrated that both OPP and SLP affected the rheological properties and filtration of the drilling mud. Notably, the density of the drilling fluid decreased significantly with the addition of crushed Sidr. Attributed to the composition of flavonoids and jujubogenin glycoside in the leaves, and citric acid in the orange peel. The specific weight of SLP and OPP (1.5 and 1.7 respectively) is considerably lower than that of bentonite (2.5), leading to a reduction in density. Sider leaves exhibited a high performance compared to orange peel, with the highest value of yield point, 10 min gel, pH observed at 20 gm of addition. The experimental findings demonstrate the impact of both materials, filtration, viscosity, and alkalinity, with Side leaves proving to be more in enhancing drilling fluid properties.

The Effects of Organically Modified Lithium Magnesium Silicate on the Rheological Properties of Water-Based Drilling Fluids.

To address the problem of insufficient temperature and salt resistance of existing polymer viscosity enhancers, we designed an organic-inorganic hybrid composite as a viscosity enhancer for water-based drilling fluids, named LAZ, and it was prepared by combining a water-soluble monomer and lithium magnesium silicate (LMS) using an intercalation polymerization method. The composite LAZ was characterized using Fourier transform infrared spectroscopy, transformed target X-ray diffractometry, scanning electron microscopy, and thermogravimetric analysis. The rheological properties of the composite LAZ were evaluated. The composite LAZ was used as a water-based drilling fluid viscosity enhancer, and the temperature and salt resistance of the drilling fluid were evaluated. The results showed that the composite LAZ presented a complex reticulation structure in an aqueous solution. This reticulation structure intertwined with each other exhibited viscosity-enhancing properties, which can enhance the suspension properties of water-based drilling fluids. The aqueous solution of the composite LAZ has shear dilution properties. As shear rate increases, shear stress becomes larger. The yield stress value of the aqueous solution increases as the composite LAZ's concentration increases. The aqueous solution of the composite LAZ exhibits strong elastic characteristics with weak gel properties. The addition of the composite LAZ to 4% sodium bentonite-based slurry significantly increased the apparent viscosity and dynamic shear of the drilling fluid. The drilling fluids containing the composite LAZ had good temperature resistance at 150 °C and below. The rheological properties of brine drilling fluids containing the composite LAZ changed slightly before and after high-temperature aging at 150 °C.

Improving Drill-String Extended Reach Efficiency in High-Temperature and High-Pressure Conditions: An Experimental Investigation

Abstract Drill string buckling behavior is of interest to the oil and gas industries. Buckling severity increases as drilling continues and causes a lock-up condition beyond which drilling cannot commence. The friction force between the drill string and the wellbore is key in influencing drill string buckling initiation and progression. Herein, the effects of adding nano-sepiolite (NSP) as an additive to water-based drilling fluids on the friction between the drill string and wellbore wall were investigated. Various samples with different sizes and compositions of NSP were tested for their ability to reduce the coefficient of friction (COF) that delays the onset of buckling to facilitate deep drilling by providing improved lubrication characteristics. The drill string sinusoidal and helical buckling and lock-up condition and the axial force transfer (AFT) were experimentally investigated. The water-based drilling fluids’ lubricity, COF between the drill string and the wellbore wall, and the stability of the rheological properties of the NSP-modified water-based drilling fluids containing 1–6 wt% NSP were tested in a high-temperature and high-pressure (HTHP) environment utilizing an in-house experimental setup. Sepiolite in nano-form at 4 wt% and with a size distribution of 30–60 nm improved the stability of the water-based drilling fluids rheology, significantly decreased the COF of the water-based drilling fluids, and improved the drill string axial force transfer. NSP additives significantly improved the COF and the drill string AFT in the HTHP environment compared with that of other commercial drilling fluids.

Investigative Study of the Properties of Low Solid Drilling Fluid Prepared by Using Iraqi Bentonite

This study aims to investigate the properties of drilling fluids with low solids content prepared using Iraqi bentonite. Polyacrylamide polymer, sodium polyacrylate polymer, Nano silica, and fine silica were used, as the results demonstrated the success of these materials in preparing drilling fluids with low solids content. As for micro silica, it is a material used with cement, but it was used in this study with drilling fluids because it is cheap in addition to being an environmentally friendly material. Polyacrylamide is a highly absorbent and effective material, which is usually used during well injection, but in this study it was used to improve the properties of Iraqi bentonite. 10 samples of drilling mud were prepared using the aforementioned materials in different proportions, and Iraqi bentonite was also used as a dispersant or dispersant phase. The percentage of bentonite during preparation ranged between (1.5-5) % in order to achieve sufficient gel resistance and balance the filtration speed. By drawing the relationship between shear stress and shear rate, it was found that all prepared samples follow the power law model, as this was used in hydraulic calculations in order to determine the pressure loss in the hydraulic system of the well. The results show that polyacrylamide polymer has the best effect on Iraqi bentonite among the other used materials in this study, where 1% from this material is enough to enhance properties (rheology and filtration) of Iraq bentonite. However, it has been observed from the laboratory results that when the percentage of bentonite is reduced to 1.5%, the prepared liquid will fail to suspend the barite and therefore will not achieve the required density in spite of the addition of barite. The best sample for the drilling fluid is when the percentage of the total solid is 5%, i.e. (10 gm Iraqi bentonite, 7 gm barite, 1 gm polymeric, Nano, or nanomaterials). As this drilling fluid had the best performance in terms of pressure loss, as they gave the least pressure loss.

Optimization of Water Based Drilling Fluid Properties with the SiO2/g-C3N4 Hybrid.

Drilling fluids are an essential component of drilling operations in the oil and gas industry. Nanotechnology is being used to develop advanced drilling fluid additives. This study looked at the viability of synthesizing SiO2/g-C3N4 hybrid extending the Stober process followed by its addition in different concentrations to water-based drilling fluids and studying impact on the rheological and fluid loss properties of the fluids. The synthesized hybrid was analyzed using XRD, SEM, TGA, and FTIR. Subsequently, it was used to develop the water-based drilling mud formulations and subjected to measurements in accordance with API standard practices. The studies were carried out at various SiO2/g-C3N4 nanoparticle concentrations under before hot rolling (BHR) and after hot rolling (AHR) conditions. The outcomes demonstrated that the rheological and fluid loss properties were enhanced by the addition of SiO2/g-C3N4 nanoparticles, as it worked in synergy with other additives. Additionally, it was discovered that the nanoparticles improved the drilling fluid thermal stability. The experimental findings indicate a significant influence of SiO2/g-C3N4 nanoparticles on base fluid properties including rheology and fluid loss as the most remarkable, especially at higher temperatures. The significant improvements in yield point and 10 s gel strength were 55 and 42.8% under BHR and 216 and 140% under AHR conditions, respectively. Permeability plugging test (PPT) fluid loss was reduced by 69.6 and 87.2% under BHR and AHR conditions, respectively, when 0.5 lb/bbl nanoparticles were used in formulations. As a result, SiO2/g-C3N4 nanomaterial has the potential to be used as drilling fluid additive in water-based drilling fluids.

A comprehensive study of the effect of multi-walled carbon nanotubes as an additive on the properties of oil-based drilling fluids

A comprehensive study of the effect of multi-walled carbon nanotubes as an additive on the properties of oil-based drilling fluids

Exploring the effect of AC/TiO2 nanoparticles and polyanionic cellulose on water-based drilling fluid properties: an integrated approach of experiment and CCD

Exploring the effect of AC/TiO2 nanoparticles and polyanionic cellulose on water-based drilling fluid properties: an integrated approach of experiment and CCD

Interpretable Lost Circulation Analysis: Labeled, Identified, and Analyzed Lost Circulation in Drilling Operations

Summary Lost circulation (LC) is a serious problem in drilling operations, as it increases nonproductive time and costs. It can occur due to various complex factors, such as geological parameters, drilling fluid properties, and operational drilling parameters, either individually or in combination. Therefore, studying the types, influencing factors, and causes of LC is crucial for effectively improving prevention and plugging techniques. Currently, the expert diagnosis of LC types relies heavily on the experience and judgment of experts, which may lead to inconsistencies and biases. Additionally, difficulties in obtaining data or missing important data can affect the efficiency and timeliness of diagnosis. Traditional physical modeling methods struggle to analyze complex factor correlations, and conventional machine learning techniques have limited interpretability. In this paper, we propose an interpretable lost circulation analysis (ILCA) framework that provides a new method for analyzing LC. First, we use Gaussian mixture model (GMM) clustering to analyze the LC characteristics of regional case data, efficiently and accurately labeling 296 LC events. Second, we establish the relationship between geological features, drilling fluid properties, operational drilling parameters, and LC types using the XGBoost algorithm. This enables timely identification of LC types during drilling operations using real-time data, with a precision greater than 85%. Finally, we use interpretable machine learning techniques to conduct a comprehensive quantitative analysis of influencing factors based on the established XGBoost model, providing a clear explanation for the identification model. This enables drilling engineers to gain deeper insights into the factors influencing LC events. In summary, the proposed ILCA framework is capable of efficiently labeling LC types based on regional case data, identifying LC types in a timely manner using real-time data, and conducting quantitative analysis of the factors and causes of LC. This approach addresses the limitations of traditional methods and offers valuable insights for drilling engineers.

An experimental investigation into the rheological behavior and filtration loss properties of water-based drilling fluid enhanced with a polyethyleneimine-grafted graphene oxide nanocomposite.

The modern oil and gas industry, driven by a surging global energy demand, faces the challenge of exploring deeper geological formations. Ensuring the robust performance of drilling fluids under harsh wellbore conditions is paramount, with elevated temperatures and salt contamination recognized as detrimental factors affecting the rheological and filtration loss properties of drilling fluids. We successfully synthesized a polyethyleneimine-grafted graphene oxide nanocomposite (PEI-GO), and its functional groups formation and thermal stability were verified through Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). Our findings demonstrated a significant improvement in the plastic viscosity and yield point of the base drilling fluid with the addition of PEI-GO. The inclusion of 0.3 wt% PEI-GO outperformed the base drilling fluid at 160 °C, improving the yield point/plastic viscosity (YP/PV) value and reducing filtration loss volume by 42% and 67%, respectively. The Herschel-Bulkley model emerged as the superior choice for characterizing rheological behavior. PEI-GO exhibited compatibility with high-salt formations, maintaining satisfactory filtration volumes even when subjected to sodium chloride (NaCl) and calcium chloride (CaCl2) contamination concentrations of up to 20 and 10 wt%, respectively. The remarkable rheological and filtration properties of PEI-GO are attributed to its electrostatic interactions with clay particles through hydrogen and ionic bonding. These interactions lead to pore plugging in the filter cake, effectively preventing water infiltration and reducing filtration loss volume. This study emphasizes the potential of PEI-GO in water-based drilling fluids, particularly in high-temperature and salt-contaminated environments.

Evaluation the effect of wheat nano-biopolymers on the rheological and filtration properties of the drilling fluid: Towards sustainable drilling process

Drilling fluid plays a crucial role in the drilling operation of the oil and gas wells by serving various functions including controlling formation pressures, preserving borehole stability, and removing drill cuttings. However, the loss of the drilling fluid into formations can lead to the permeability damage, groundwater contamination, and altered formation integrity. In addition, the waste generated from drilling activities poses environmental issues, particularly when drilling fluids containing substances, such as heavy metals are discarded. Water-based drilling fluids (WBDFs) are preferred due to their eco-friendliness and cost-effectiveness. However, they suffer from inadequate rheological and filtration properties, prompting the introduction of additives. This study evaluates the use of wheat grain as nano-biodegradable additives in WBDFs, focusing on different sizes of wheat powder ranging from nano to course particle size. Nano-biopolymers (WNBPs) were prepared from breaking down into the nanosized structure using the ball mailing approach and characterized using XRF, FTIR, TGA, DLS, SEM and TEM. Several drilling fluids including the reference, modified, biodegradable and nano-biodegradable drilling fluids were prepared from API SPEC 13A standard, carboxymethyl starch (CMS), wheat powder (WP) at 75–600 µm and nano-biopolymer (WNBPs), respectively. The formulated drilling fluids were investigated by conducting different measurements, such as pH, rheology, filtration and modeling. The obtained results show that the nano-biodegradable exhibited alkaline pH above 10 that keeps the drillpipe and equipment from the corrosion. The developed WNBPs exhibited a significant role in improving the rheological properties of the reference drilling fluid but not effective as CMS. The maximum gel strength of 957.6 pa was obtained from adding 2 wt% WNBPs and increased 1100 pa when temperature increased to 70 °C. Meanwhile, the same wheat nanoparticles enabled increasing the plastic viscosity from 0.03 to 0.09 pa.s and decreased to 0.07 pa.s under the influence of high temperature. In terms of the thinning behavior, the prepared wheat powders exhibited a significant role in providing the thinning behavior of the developed drilling fluids compared with the reference drilling fluid and CMS-modified drilling fluid. Adding 2 wt% WNBPs to the reference drilling fluid decreased the fluid loss from 19.5 to 14 mL but fine WPs have a stronger effective on the filtration properties and lowered the filtration rate to 11.5 mL.

Microwave-assisted synthesis of zinc oxide nanoflowers for improving the rheological and filtration performance of high-temperature water-based drilling fluids

Zinc Oxide (ZnO) nanostructures have proved useful across a wide range of applications like medical technology, electronics, sulfur removal as well as microbial growth control. In the petroleum industry, ZnO nanostructures have been widely researched for application in Drilling Fluids. ZnO has been previously reported to work excellently in enhancing the electrical and thermal properties of water-based drilling fluids (WBDFs). However, the role of morphological features of the nanostructures in influencing the properties of bentonite-laden WBDFs is less understood. In this work, ZnO nanostructures were synthesized under microwave irradiation which resulted in different shapes like rods and flowers. The effect of microwave power and time was observed with Field Emission Scanning Electron Microscopy (FE-SEM) and Dynamic Light Scattering (DLS), and a suitable synthesis criterion was selected for achieving the smallest complex ZnO nanoflowers. These nanoflowers were further characterized for functional group and structural identification. Bentonite/Polymer Nanofluids were prepared and tested for properties like rheology, API, and HPHT filtration before and after thermal aging at 150 °C. The results show ZnO nanoflowers in WBDFs have excellent filtration control ability with ∼56% reduction in HPHT filtrate volume and can impart a flat-line rheological profile. Also, the breaking of nanoflowers into smaller nanorods and some further textural changes is predicted to enhance the stability of the WBDFs due to better dispersion and compact mud cake formation. The study shows that the morphological features of metal oxide nanostructures can be controlled with microwave irradiation and play an effective role in controlling the properties of bentonite/polymer WBDFs.

An Amphiphilic Multiblock Polymer as a High-Temperature Gelling Agent for Oil-Based Drilling Fluids and Its Mechanism of Action.

Oil-based drilling fluids are widely used in challenging wells such as those with large displacements, deepwater and ultra-deepwater wells, deep wells, and ultra-deep wells due to their excellent temperature resistance, inhibition properties, and lubrication. However, there is a challenging issue of rheological deterioration of drilling fluids under high-temperature conditions. In this study, a dual-amphiphilic segmented high-temperature-resistant gelling agent (HTR-GA) was synthesized using poly fatty acids and polyether amines as raw materials. Experimental results showed that the initial decomposition temperature of HTR-GA was 374 °C, indicating good thermal stability. After adding HTR-GA, the emulsion coalescence voltage increased for emulsions with different oil-to-water ratios. HTR-GA could construct a weak gel structure in oil-based drilling fluids, significantly enhancing the shear-thinning and thixotropic properties of oil-based drilling fluids under high-temperature conditions. Using HTR-GA as the core, a set of oil-based drilling fluid systems with good rheological properties, a density of 2.2 g/cm3, and temperature resistance up to 220 °C were constructed. After aging for 24 h at 220 °C, the dynamic shear force exceeded 10 Pa, and G' exceeded 7 Pa, while after aging for 96 h at 220 °C, the dynamic shear force exceeded 4 Pa, and G″ reached 7 Pa. The synthesized compound HTR-GA has been empirically validated to significantly augment the rheological properties of oil-based drilling fluids, particularly under high-temperature conditions, showcasing impressive thermal stability with a resistance threshold of up to 220 °C. This notable enhancement provides critical technical reinforcement for progressive exploration endeavors in deep and ultra-deep well formations, specifically employing oil-based drilling fluids.

Effects of nanosilica on the properties of brine-base drilling fluid

In the process of drilling oil and gas wells, the shrinkage and falling of wellbore walls are often caused by the expansion of mud shale water. To date, conventional additives have been unable to plug the pore throats of shale rock with nanoscale pores and thus cannot effectively solve the problem of wellbore instability encountered in shale formation drilling. In view of this situation, the idea of using nanosilica to plug the nanopore throat of mud shale is proposed to reduce its permeability and to slow water intrusion. The influences of nanosilica on the properties of brine-base drilling fluid drilling fluid are evaluated by measuring the viscosity, filtration loss and swelling of the drilling fluid. The results of laboratory experiments show that the improvement in drilling fluid properties can only be achieved on the basis of salt resistance; that is, a salt-resistant soil slurry should be used. A concentration of 1–5% nanosilica can improve the viscosity of the drilling fluid by increasing the internal friction between particles. However, nanosilica materials are sensitive to salt concentration. Nanosilica particles can be deposited on the surface of a filter cake to block the pores of the filter paper, and the filtration loss reduction rate can reach 40.2%. Blocking the pores of the clay plays a role in preventing the clay from absorbing water and expanding. The optimal addition amount of silica is 3%, and its salt resistance can reach 16%. Considering the experimental results of filtration loss, swelling amount and cost performance, 3%NP + 4%NaCl + SWM-B is selected as the optimal formula. The results of this study can be applied to effectively improve the phenomenon of wellbore instability during drilling in shale formations, and it has important application value.

Oily bioorganoclays in drilling fluids: Micro and macroscopic properties

The application of organoclays as an additive to improve the performance of oil-based drilling fluids has long been a subject of research. In this work, montmorillonite containing zinc cations was modified by lecithin to synthesize organic montmorillonite (ZnOMt), which was then dispersed in vegetable and mineral oils for the preparation of oil-based drilling fluids. Their viscoelastic properties were evaluated and linked to ZnOMt microstructure information obtained by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). The nature of the oil used and the heating temperature are key parameters influencing the performance of oil-based drilling fluid. The favorable properties of vegetable oil-based drilling fluids containing organoclays provide great potential for their application in drilling engineering.

The Monitoring of Abnormal Fluid Properties Based on PCA Technique as an Alternative Strategy to Support Autonomous Drilling Operations

Summary The well drilling process requires constant monitoring to ensure that the properties of the drilling fluids remain within acceptable ranges for safe and effective operation of the well drilling process. The present work developed a principal component analysis (PCA)-based methodology for diagnosing anomalies in drilling fluids, and detecting and identifying abnormal drilling fluid properties during well drilling operations. The main novelty of the present work regards the application of multivariate techniques for diagnosing anomalies (faults) in drilling fluids, increasing the literature on fault diagnosis techniques applied to the petroleum industry, and producing a promising methodology for field applications. The proposed technique was implemented and validated in a pilot drilling fluid production unit through continuous online monitoring of the conductivity, density, and apparent viscosity of drilling fluids. Model training was carried out with data collected during assisted normal operation, allowing detection of abnormal conditions with less than 1% of false positives and less than 0.5% of false negatives. Additionally, the proposed methodology also allowed the correct diagnosis of the observed faults. The results indicated that PCA-based approaches can be used for the online monitoring of drilling fluid properties and fault diagnosis in real well drilling operations.