Properties Of Water-based Drilling Fluids Research Articles

Enhancing the Rheological Properties of Water-Based Drilling Fluid Using Micronized Starch

The water-based drill-in fluid should be designed to have a good carrying capacity (yield point) and an ideal filter cake (thin, impermeable, and fast formed). The ideal filter cake will reduce the fluid loss and decrease the formation damage. In addition, thin filter cake will help avoid the common drilling problem such as differential sticking and this will reduce the total drilling cost. The common drilling fluid additive that can be used to minimize the fluid loss is starch, which has two unique features, environmentally friendly and cheap additive. The aim of this paper is to assess the effect of using the micronized starch as a fluid loss control additive to the drilling fluid. Different starch sizes were used such as $$60\,\upmu \hbox {m}$$ , $$7\,\upmu \hbox {m}$$ , and $$1\,\upmu \hbox {m}$$ . Laboratory measurements using gas chromatography, field emission scanning electron microscope, and transmission electron microscopy were used to evaluate the micronized properties. High-pressure high-temperature filtration device was used to assess the filtration properties at $$250\,^{\circ }\hbox {F}$$ and 500 psi. The effect of starch size on the drilling fluid rheological properties such as gel strength, yield point, apparent viscosity, and plastic viscosity was investigated at $$80\,^{\circ }\hbox {F}$$ . The results obtained showed that adding micronized starch to water-based drilling fluid increased the yield point and the plastic viscosity by 250% with an optimum yield point/plastic viscosity (YP/PV) ratio of 1.5. Filtration test at $$250\,^{\circ }\hbox {F}$$ and 300 psi indicated that decreasing the starch size from 60 to $$1\,\upmu \hbox {m}$$ resulted in reducing the fluid loss volume by 50% and decreased the filter cake thickness by 35%. These results indicated that the starch micronized-based ( $$1\upmu \hbox {m}$$ ) drilling fluid was efficient in forming a thin, and impermeable filter cake.

Evaluating the Effect of Using Micronized Barite on the Properties of Water-Based Drilling Fluids

Solids sag and formation damage are serious problems encountered while drilling with barite-weighted drilling fluids. The objective of this study is to investigate the effect of reducing barite particle size on rheological properties, fluid stability, and filter cake removal. Barite samples with different particle sizes were prepared using sieve analysis and ball milling technique. Micronized barite (8 μm) showed a moderate stability with zeta potential measurements for a pH range greater than 8. Solubility tests showed good enhancement in barite removal as the particle size was reduced, with a difference of around 11 g/L between the largest size (75-106 μm) and the micronized size of barite. HPHT filtration test results confirmed the solubility results with 5 wt.% enhancement in filter cake removal efficiency as barite particle size was reduced to micronized size. [Received: December 4, 2017; Accepted: December 17, 2018]

Enhancing wellbore stability of coal measure strata by electrical inhibition and wettability control

The co-exploitation of coal measure gases (CMG) in coal measure strata put forward higher requirements on water-based drilling fluid (WBDF). Among these reservoir rocks, it is well-known that coal rocks and shales are strata subject to wellbore instability problems. In this study, mixed metal hydroxide (MMH) was used to inhibit the hydration of clay minerals in coal rock and shale. Meanwhile, compound surfactants were employed to enhance the hydrophobicity of reservoir rocks, thus decreased the chance of drilling fluid-rock interaction and improved wellbore stability of coal measure strata. The influence of inorganic MMH and compound surfactants on the properties of WBDF was studied and an optimized WBDF based on electrical inhibition and wettability control (EW-WBDF) was proposed. Comprehensive evaluation on the properties of the EW-WBDF and its capability to enhance the wellbore stability of coal measure strata was conducted. Results manifested that inorganic MMH had excellent inhibitive performance. On the other hand, the contact angles of compound surfactants solution with coal rock and shale were up to 102° and 91°, respectively, which indicated that the compound surfactants could enhance the hydrophobicity of coal rocks and shale effectively. Further pore pressure transmission tests showed that, compared with fresh water, the compound surfactants and inorganic MMH could significantly retard the pore pressure transmission speed in coal rocks and shale, and decreased the permeability of rocks with a rate up to 99%. The contact angles of the EW-WBDF with coal rock and shale were 77.5° and 66.5°, respectively. The EW-WBDF had excellent inhibition performance to clay minerals and salt resistance capability which could resist the contamination of 1% CaCl2, 1% MgCl2, 5% NaCl, and 5% attapulgite respectively, at ambient temperature and 80 °C. More importantly, as a drill-in fluid, it showed a very low formation damage rate (3.8%) to the original coal rock, while the damage rate of common WBDF to coal rock was 36%. This study provides a guideline for the design of WBDF in the co-exploitation of CMG in coal measure strata.

Rheological investigation of smart polymer/carbon nanotube complex on properties of water-based drilling fluids

Carbon-based nano-materials and polymers are the most propitious materials proposed to cure the serious problems encountered in drilling operation. The aim of this study is to improve the essential properties of selected water-based drilling muds (WBMs) using a new synthesized complex of oxidized multi-walled carbon nanotube wrapped by polyethylene glycol (POCNT). A rotational rheometer and an API filter press were used to analyze the rheological and filtration properties of the drilling muds, and smart hydrophilic and hydrophobic behaviors were expected due to carboxylic bonds and PEG polymer chains. It has been shown that adding a relatively low amount of POCNT to selected water-based muds will lead to a significant improvement in rheological behaviors of the drilling fluid, and a noticeable reduction in their associated formation damage. Specifically, the presence of POCNT in WBMs has shown to enhance the viscosity, yield stress, and subsequently the carrying capacity of the drilling muds at several temperatures. Moreover, it has been indicated that this formulation could properly decrease the permeability of mud cake, and as a result, reduce the filtration volume of nanofluids compared with that of base fluid by up to 82%. At the end, the curve fitting analysis proves that the Herschel- Bulkley method better fits the rheological behaviors of this new nano drilling fluid.

Tribological properties of water-based drilling fluids with borate nanoparticles as lubricant additives

In this work, several nanostructured borates such as magnesium, zinc, aluminum and titanium borates were synthesized. These borates were added to drilling muds and their ability to improve tribological properties of water-based drilling fluids, was investigated. The tribological properties of the fluids containing these nano-additives were compared with those of a typical mud (containing bentonite and water) with and without a commercial lubricant additive (BitcLub, M − I SWACO) as reference samples. The results indicated that adding nano-additives to the drilling mud increased its extreme pressure property by more than five times compared to the reference samples. At the same time, these nano-additives decreased the coefficient of friction due to their good ability in producing a strong protective film (tribo-film) on the contacting surfaces being stable at extremely high pressure and temperature conditions. Among all the prepared nano-additives, titanium borate, which is biodegradable, showed a significant improvement in tribological properties of drilling fluid as compared to the other borates.

Experimental investigation of rheological and filtration properties of water-based drilling fluids in presence of various nanoparticles

For the past decades, considerable attention has been focused on the manufacture of a high-performance, environmentally compliant water-based mud system to be a better choice than oil and synthetic-based muds (OBM/SBM). However, the improvement of WBMs has not reached the satisfactory level yet and attempts in this regard should be continued. Accordingly, in this study, an attempt was made to improve the performance of a Bentonite-WBM by adding four types of hydrophilic nanoparticles (NPs), namely aluminum oxide (Al2O3), titanium dioxide (TiO2), silicon dioxide (SiO2), and copper oxide (CuO). The NPs were dispersed in the drilling fluid with concentrations of 0.01, 0.05, 0.1 and 1 wt%. The results revealed that the Al2O3 NPs increased the amount of mud filtration up to 80% while the mud cake quality became poorer as compared to the based mud. In contrast, the amount of mud filtration had a decreasing trend when SiO2, TiO2 and CuO NPs were applied especially at the concentration below 0.5 wt%. Rheological properties and gel strength were also improved in the presence of TiO2, Al2O3 and CuO NPs in comparison with the based mud. Overall, it was concluded that adding of the NPs at concentrations below 0.5 wt% to the Bentonite-WBM has potential to improve rheological and filtration properties.

Improvement in filtration properties of water-based drilling fluid by nanocarboxymethyl cellulose/polystyrene core\u2013shell nanocomposite

Since almost all drilling problems directly or indirectly relate to drilling fluid, improvement in drilling fluid significantly enhances drilling operations. Drilling fluid contains base fluid, suspended solid particles and chemicals. Recently, nanoparticles have been widely recommended for improvement in drilling fluid properties. The main purpose of this study was to improve the rheological and filtration properties of water-based drilling fluid through adding new additive carboxyl methyl cellulose (CMC)/polystyrene core–shell nanocomposite. It compares filtration and rheological behavior of CMC, nanoCMC and core–shell nanocomposite. The core–shell nanocomposite was synthesized by miniemulsion polymerization method, and nanoCMC and core–shell nanocomposite were characterized by scanning electron microscope, transmission electron microscopy, particle size analyzer and thermogravimetric analysis. Fluid loss, mud cake thickness, viscosity, weight and pH of drilling fluid with core–shell nanocomposite additive were compared with conventional CMC (bulk CMC) and nanoCMC particles. Results showed a significant decrease in mud cake thickness and fluid loss when the core–shell nanocomposite was used, as compared with conventional CMC and nanoCMC. Viscosity of three additives has same trend with insignificant change while less yield point is obtained for drilling fluid containing core–shell nanocomposites. Mud weight and pH were almost the same for all three additives. Thus, the core–shell nanocomposite can be an alternative additive to control mud cake thickness and fluid loss while maintaining other main properties in an acceptable range.

Experimental study on the application of an ionic liquid as a shale inhibitor and inhibitive mechanism

Wellbore instability is caused to a great degree by shale hydration, which results from the interaction between the exposed shale formation and water-based drilling fluids in the exploration of oil and natural gas reservoirs. In this paper, an ionic liquid (ILB) is utilized as an efficient shale inhibitor in water-based drilling fluids to minimize shale hydration. The inhibitive property of ILB is evaluated by hot-rolling dispersion, capillary suction time and bentonite swelling tests. The test results indicate that 0.05wt% ILB exhibits superior inhibition performance than 5wt% conventional inhibitor potassium chloride (KCl) and its inhibition effect is approximately equal to that of 2wt% polyether diamine (PA). But different from KCl and PA, the presence of low concentration of ILB can also improve the rheological properties of water-based drilling fluids at high temperature, and meanwhile has no adverse effect on their filtration property. The investigation of inhibition mechanism indicates that the thermal stability of Na-Mt is greatly improved due to the intercalation with cationic group of ILB, leading to excellent inhibition property of ILB at high temperature. Furthermore, the adsorption of ILB in the interlayer of Na-Mt weakens the hydrophilicity of Na-Mt, which further inhibits water ingress.

Zwitterionic Polymer P(AM-DMC-AMPS) as a Low-Molecular-Weight Encapsulator in Deepwater Drilling Fluid

In deepwater oil and gas drilling, the high-molecular-weight encapsulator aggravates the thickening of the drilling fluid at low temperatures. Therefore, it is hard to manage the downhole pressure, and drilling fluid loss occurs. In this paper, a zwitterionic polymer P(AM-DMC-AMPS) which was the terpolymer of acrylamide, methacrylatoethyl trimethyl ammonium chloride, and 2-acrylamido-2-methylpropane sulfonic acid, was developed as a low-molecular-weight encapsulator. It was characterized by Fourier transform infrared spectrum analysis, nuclear magnetic resonance, and gel permeation chromatography. Moreover, the low-temperature rheology, shale inhibition and filtration properties of water-based drilling fluids (WBDFs) containing different encapsulators were experimentally investigated and compared. The results showed that the molecular weight of P(AM-DMC-AMPS) was about 260,000, much lower than that of the conventional encapsulators. In the deepwater drilling temperature range 4–75 °C, WBDF containing P(AM-DMC-AMPS) had lower and more stable rheological property because of its short molecular chains. The high shale recovery rate and low swelling rate indicated its strong shale inhibition performance, owing to its adsorption on the clay surface and the wrapping effect through both hydrogen bonding and electrostatic interaction. It also improved the filtration property of WBDF, and was compatible with other WBDF components. This product is expected to simultaneously realize the good encapsulation performance and low-temperature rheological property for deepwater drilling fluid.

Rheological Properties of Polymer Drilling Fluid Developed for Permafrost Natural Gas Hydrate Drilling

The rheological properties of water-based drilling fluids are heavily influenced by low temperatures and are some of the most important issues for permafrost natural gas hydrate drilling. In this work, we developed a polymer drilling fluid formula and studied its rheological properties at low temperatures. The rheological properties of four different drilling fluids including macro-polymers, amphoteric polymers, sulfonated polymers, and biopolymers were tested. The corresponding rheological-property/temperature response curves were drawn. The response characteristics of the rheological properties with temperature were analyzed. Based on these, a novel research idea was developed to adapt to permafrost drilling a poly-sulfonate drilling fluid system in which sulfonated lignite (SMC) and sulfonated phenolic resin (SMP) were used as the main agents while xanthan gum (XC) served as a flow-pattern modifier. According to orthogonal test results, the optimized drilling fluid formula was base mud + NaCl (20 wt. %) + NaOH (0.1) + SMP (3) + SMC (4) + XC (0.3). Moreover, the rheological-property/temperature response mechanism was analyzed using Fourier transform infrared (FT-IR) spectroscopic tests of the treating agents and scanning electron microscopic (SEM) tests of the mud cakes.

Application of TiO2/Polyacrylamide Core–Shell Nanocomposite as an Additive for Controlling Rheological and Filtration Properties of Water-Based Drilling Fluid

Application of TiO₂/Polyacrylamide Core–Shell Nanocomposite as an Additive for Controlling Rheological and Filtration Properties of Water-Based Drilling Fluid

Intercalation behavior of branched polyethyleneimine into sodium bentonite and its effect on rheological properties

The inhibitive mechanism of low-molecular-weight branched polyethyleneimine (BPEI) with multiple primary amines and 1,6-hexamethylenediamine (HMDA) with two primary amines adsorbed on sodium bentonite (Na+Bent) has been investigated using isothermal adsorption, adsorption kinetics, scanning electron microscopy (SEM), X-ray diffraction (XRD) and elemental analysis (EA) techniques. The results indicate that as the number of primary amine groups in the inhibitor increases, the saturated adsorption amount decreases, and the adsorption rate increases. Low-molecular-weight BPEI molecules enter the interlayer space of Na+Bent and significantly reduce this space compared to that in hydrated Na+Bent. Moreover, there is no change in the clay interlayer space of Na+Bent with increasing BPEI concentration. A monolayer of BPEI intercalates into the clay interlayer and replaces the sodium ions in the interlayer. The BPEI molecules become firmly embedded in the Na+Bent interlayer between the primary amine groups and Si-O groups, resulting in the removal of water molecules. The inhibitive performance shows that BPEI inhibits clay hydration more effectively than HMDA and other inhibitors, and also indicates that as the number of primary amines increases, the inhibitive performance increases. When <1wt% BPEI was added, the rheological properties improved significantly, and the American Petroleum Institute standard (API) fluid loss could be controlled well, indicating that BPEI can effectively create a balance between swelling inhibition and the rheological properties of water-based drilling fluids. Overall, the results indicate that BPEI is promising as a commercial shale inhibitor.

Influence of an ionic liquid on rheological and filtration properties of water-based drilling fluids at high temperatures

Ionic liquids have attracted significant research interest due to their unique thermal stability. In this paper, the influence of a water-soluble ionic liquid on the rheological and filtration properties of water-based drilling fluids at high temperature is investigated. The drilling fluids are evaluated by means of rheological and filtration tests following the American Petroleum Institute (API) standards, submitted to an aging process or at high temperature. The experimental results show that the rheological behavior of water-based drilling fluids is improved and enhanced in the presence of low concentration of ionic liquid (as low as 0.05mass%) at high temperatures (even up to 240°C). Meanwhile, the high-temperature and high-pressure (HTHP) filtration volumes are reduced by as much as 52% compared with that of polymer water-based drilling fluids without ionic liquid. The study of the mechanism demonstrates that the water-soluble ionic liquid have an excellent capacity to improve the rheological and filtration properties of water-based drilling fluids at high temperatures due to the high thermal stability and cation exchange ability of the ILA.

Influence of Clay Swelling Inhibitor in Filtration Properties of Water-Based Drilling Fluids

This work aims to evaluate the influence of the clay swelling inhibitor in the filtration properties of water-based drilling fluids. Drilling fluids were prepared with and without adding potassium citrate clay inhibitor. The following additives were used in the composition of the fluid: viscosity agent (xanthan gum), filtrate reducer (starch and low viscosity carboxymethylcellulose (CMC LV)), antifoam, bactericide, sealant (calcite), lubricant and pH controller. The concentration of inhibitor was used of 15, 20, 25 and 30 g/ 350 mL of water. We determined the filtration properties (filtrate volume (FV), spurt loss (SL), cake thickness (CT) and permeability (K)) of drilling fluids. According to the results, it was concluded that: (i) adding the inhibitor to the fluid promoted reduction of FV and K of fluids containing starch in the composition and (ii) the inhibitor promoted satisfactory reductions in the CT and increased of SL for all the studied fluids. Finally, the inhibited fluids prepared with higher concentrations of starch, CMC LV, calcite and potassium citrate than 25 g/ 350 mL of water showed the best performance compared to FV and SL.

Effect of Nanofluids of CuO and ZnO in Polyethylene Glycol and Polyvinylpyrrolidone on the Thermal, Electrical, and Filtration-Loss Properties of Water-Based Drilling Fluids

Summary The challenges in drilling problems such as formation damage, pipe sticking, lost circulation, poor hole cleaning, and fluid loss need better solutions. Nanotechnology, by means of nanofluids, provides potential solutions for the development of improved water-based mud (WBM). This work presents the use of nanofluids of CuO and ZnO prepared in various base fluids, such as xanthan gum, polyethylene glycol, and polyvinylpyrrolidone (PVP), which are commonly used in oilfield operations, for the development of nanofluid-enhanced drilling mud (NWBM). In this paper, formulations of various nanofluids with varying concentrations of nanoparticles, such as 0.1, 0.3, and 0.5 wt%, were investigated for their effect on the thermal, electrical, and fluid-loss properties of NWBM. In addition, these results also were compared with those obtained with microfluids of CuO and ZnO for the microfluid-enhanced drilling mud (MWBM) to understand the effect of particle size. It is observed that the use of nanofluids in WBM helps to improve their thermal properties, with an associated direct impact on their cooling efficiency at downhole and surface conditions compared with those using microfluid. Filtration-loss and filter-cake-thickness studies on WBM, MWBM, and NWBM were also carried out with an American Petroleum Institute (API) filter press. It is observed that the fluid loss decreases with addition of the nanofluids and microfluids in WBM, with nanofluids showing an improved efficacy over microfluids. The studies, in general, bear testimony to the efficacy of nanofluids in the development of next-generation improved water-based drilling fluids suitable for efficient drilling.

The novel approach for the enhancement of rheological properties of water-based drilling fluids by using multi-walled carbon nanotube, nanosilica and glass beads

Abstract Nano and micron materials are investigated in water-based drilling fluid (WBDF) to improve its rheological behaviour. Due to the environmental and certain operational concerns, the use of oil-based drilling fluid (OBDF) and synthetic based drilling fluid (SBDF) is restricted that caused the industry seeking for new ways to enhance rheological properties of WBDF. This study was based on investigating the applicability of multi-walled carbon nanotube (MWCNT), nanosilica and glass beads (GBs) as primary additives for enhancing the filtrate volume, lubricity and other rheological properties of WBDF. This study focused on the effect of different concentrations such as 0.001 ppb, 0.002 ppb, 0.01 ppb, 0.02 ppb, 0.1 ppb, and 0.2 ppb of each MWCNT and nanosilica over the rheological performance of WBDF. Effect of GBs of different sizes such as (90–150 μm) and (250–425 μm) was investigated at different concentrations of 2 ppb, 4 ppb, 6 ppb, 8 ppb, 10 ppb, and 12 ppb over rheological performance of WBDF. Results revealed that coefficient of friction (CoF) for drilling fluid without nanoparticles and GBs was 0.238. 0.01 ppb of MWCNT and nanosilica provided 44% and 38% CoF reduction. 4 ppb of GBs (90–150 μm) provided 28% CoF reduction. MWCNT showed 4.5 ml of filtrate volume and 2/32 inch of mud cake thickness. Thus, MWCNT can be a better choice as a drilling fluids additive for WBDF.

Effects of tribological properties of water-based drilling fluids on buckling and lock-up length of coiled tubing in drilling operations

This study evaluates the performance of three lubricants on reducing friction between wellbore and coiled tubing (CT) and hence improving axial force transfer, reducing buckling, and enhances the limited reach of CT. The lubricants were evaluated using water-based drilling fluids composed of lubricants of different concentrations. Experiments were conducted in a lubricity tester and by using an in-house experimental setup that imitates the wellbore being drilled in the presence of drilling fluids. Results showed that reducing COF does not change CT buckling shape or mode, but it alters the initiation and transition between buckling modes and increases lock-up length. Effects of increasing lubricants percentages on mud properties were also examined. They showed positive impact compared to tests conducted without lubricants.

Filter Cake Properties of Water-Based Drilling Fluids Under Static and Dynamic Conditions Using Computed Tomography Scan

Previous studies considered the water-based drilling fluid filter cake as homogenous, containing one layer with an average porosity and permeability. The filter cake was recently proved to be heterogeneous, containing two layers with different properties (thickness, porosity and permeability). Heterogeneity of the filter cake plays a key role in the design of chemical treatments needed to remove the filter cake. The objectives of this study are to describe filter cake buildup under static and dynamic conditions, determine change in the filter medium properties, and obtain the local filtration properties for each layer in the filter cake. A high pressure high temperature (HPHT) filter press was used to perform the filtration process at 225 °F and 300 psi. A CT (computed tomography) scanner was used to measure the thickness and porosity of the filter cake. The results obtained from the CT scan showed that under static conditions, the formation of filter cake changed from compression to buildup; while under dynamic conditions, the filter cake was formed under continuous buildup. The CT results explained the changes in the thickness and porosity of each layer of the filter cake with time. The CT scans showed the change in the properties of the ceramic disk, such as porosity and permeability, which affect the calculation of the filter cake permeability. The change of the properties of the filter medium was ignored in previous studies.

Artificial Neural Network Modeling of Plastic Viscosity, Yield Point, and Apparent Viscosity for Water-Based Drilling Fluids

A feed-forward multilayer perceptron neural network model with Levenberg-Marquardt learning algorithm has been developed to predict rheological properties of water-based drilling fluids. The developed model was based on a three-layer network containing input, hidden, and output layer. The sigmoid function was applied as the transfer function in the hidden layer and linear transfer function in the output layer. Two statistical parameters, mean square errors and correlation coefficient, were used as a criterion for evaluating artificial neural network modeling performance. Accordingly, a comparison between experimental values and those predicted by the artificial neural network showed a good coincidence proving its high accuracy in estimating target value.

Effects of carbon ash on rheological properties of water-based drilling fluids

The rheological properties of drilling fluid play a fundamental role in drilling operations, and the water-based drilling fluid is based on bentonite dispersion. According to Bingham-plastic model, the influences of carbon ash and commercial rheological modifier (RM) on rheological properties of bentonite dispersion are investigated systematically from apparent viscosity (AV), plastic viscosity (PV), yield point (YP) as well as the ratio of yield point and plastic viscosity (RYP). The results indicate that the rheological properties of bentonite dispersion with carbon ash are improved markedly in YP, and especially for the low solid content of bentonite dispersion. The filtration and density test are also carried out using an API Filter Press and mud balancer respectively. From the results, it could be observed that the filtrate loss and filter cake thickness increase dramatically whereas the density of bentonite dispersion decreases slightly as the addition of carbon ash increases. Furthermore, the stability of bentonite dispersion incorporated with carbon ash is evaluated. The experimental results indicate that carbon ash is better than RM in stability. Through this study, carbon ash is an excellent potential additive for improving the rheological properties of water-based drilling fluids.