Drilling Mud Systems Research Articles

Performance analysis and degradation mechanism of acrylamide co-polymer as rheology and filtrate reducers in different salt aqueous-based drilling mud systems at high-temperature conditions

To maintain performance of an aqueous-based drilling muds (ABDMs), it was imperative to understand the decay mechanism of the incorporated synthetic polymers, when exposed to the elevated temperatures. The understanding of the decay mechanism could provide a polymer replenishment strategy for the fluid to retain a specific rheology and filtrate control performance. In this context, thermal-degradation of various acrylamide co-polymers was investigated in different monovalent brines. The acrylamide co-polymers were custom synthesized, and their molecular weight and % sulfonic substitution was verified using the capillary viscometer and nuclear magnetic resonance spectroscopy techniques respectively. The co-polymer thermal degradation mechanism (i.e., polymer hydrolysis) in various monovalent brines (KCl, NaCl and NaBr) was quantified by novel titration for temperature range {121 °C, 177 °C}. The degradation response of the co-polymers was then correlated with their rheology and HPHT (high-pressure-high-temperature) filtrate performance; for instance, the titration studies showed that co-polymer degradation was 12–15% and 44–47% after sixteen hours aging at 121 °C and 177 °C respectively; correspondingly the co-polymer performance in ABDM, exhibited HPHT filtrate of 12–18 mL and 38–40 mL at those respective temperatures after sixteen hours of aging. The quantified understanding of the co-polymer thermal degradation was used to device a new approach for co-polymer replenishment strategy; it was illustrated that a 7% replenishment of the co-polymer for every eight hours, at 121 °C, enabled sustained HPHT filtrate of 12–18 mL for the studied evaluation period of thirty-two hours. The replenishment approach presented in the study would provide a valuable tool for drilling automation to ensure sustained fluid performance.

Optimizing filtration properties of water based drilling mud systems using dually modified starch

This research explores the efficacy of dually modified starch as a fluid loss controlling agent in drilling mud systems, aiming to optimize filtration properties for improved borehole stability and reservoir productivity. Filtrate loss and filter cake thickness (API and HPHT) were examined under varying conditions, focusing on the influence of degree of substitution (DS) of the starch, CMITS concentration, salt concentration, and temperature. The current findings reveal that DS 0.66 starch exhibited the highest reduction in filtrate volume and cake thickness, achieving an 81% decrease at 8 ppb concentration. Regression models accurately predicted filtration properties and were confirmed through additional experiments. Comparison with previous studies underscores the potential of modified starch as a cost-effective alternative for drilling mud additives. Furthermore, the correlation between viscosity and filtration properties was explored, highlighting its impact on improved filtration characteristics. Overall, this research contributes valuable insights into enhancing drilling efficiency and borehole stability, minimizing dependence on costly chemical additives.

Experimental Study on the Performance of Frictional Drag Reducer with Low Gravity Solids

Reducing energy consumption during drilling operations is beneficial to both the environment and economy. Frictional drag reducers (FDR) are widely used to reduce the energy loss caused by turbulent flow. FDR plays an important role in flow lines as they can reduce the frictional pressure drop effectively, and benefit the selection of circulating fluid and pump. However, several factors can influence the performance of FDR, including fluid additives and incorporated solids, such as drill solids. Thus, the main objective of this paper is to study the influence of low gravity solids (LGS) on the performance of the FDR. This paper is mainly based on experimental study. The experimental work contains two parts: rheology characterization and flow loop tests. Rheology characterization tests were performed to calculate the flow consistency index (K) and flow behavior index (n). Flow loop experiments were conducted for two geometry (0.457 inch and 0.797 inch diameter). Xanthan gum was used as a fractional drag reducer. Bentonite and quartz sand were added as low gravity solids. Three designed water-based mud systems are tested for drag reduction efficiency of Xanthan gum. Flow rate of the mud varied from 3 gpm to 16 gpm. Concentration of Xanthan ranged from 0.1 lbm/bbl to 0.6 lbm/bbl. Low weight solids were added with weight percentage of 0.5%, 1%, 2% and 2.5%. The result shows that xanthan gum is an efficient drag reducer for adequate reasons. Firstly, even at al low concentration, xanthan gum shows high resistance to degradation. Secondly, the maximum drag reduction with xanthan gum is up to 70.54% with a concentration of 0.6 lbm/bbl. However, the existence of different low gravity solids influence the efficiency of xanthan gum in different styles. Experiment results indicate that the higher the weight percentage of bentonite, the lower the drag reduction effectiveness. While with the increasing concentration of quartz sand, the drag reduction does not show an intense change. This study intents to give an instructive guidance on usage of frictional drag reducers in drilling mud system design. Removal of low gravity solids from the mud is difficult, which pose a danger to the drilling fluid. By understanding the effectiveness of FDR, we can reduce energy consumption when irremovable low gravity solids exist. FDR can be used for modifying the mud contents to develop a lower pressure gradient under turbulent flow condition. In the same scenario, adding FDR can suppress turbulent at a constant pressure gradient but with a higher flow rate.

Research on the Stability of the Spacer Fluid Interface in Dual-Layer Pipe Dual-Gradient Drilling

Dual-layer pipe dual-gradient drilling technology is an emerging technology for solving the problem of the narrow safety density window in deepwater drilling. The unstable spacer fluid interface in this technology directly affects the dual-gradient pressure system in the annulus, causing changes in the drilling mud performance and affecting the control of bottom hole pressure and rock removal with drilling mud. Therefore, the key to the stable operation of dual-layer pipe dual-gradient drilling technology is to maintain the stability of the spacer fluid interface. Based on this, a seawater-spacer fluid-drilling mud annular flow model was established in this study, with a bottom hole pressure control step of 0.2 MPa, and the spacer fluid height after a single control was used as the evaluation index to study the influence of annular flow velocity, the spacer fluid properties, and the drill string rotation speed on the stability of the spacer fluid interface. The results show that in the determined conditions of the seawater and drilling mud system, the annular fluid flow rate and the physical parameters of the spacer fluid are the main factors affecting the stability of the spacer fluid interface. When the annular fluid flow rate increased within the range of 0.04~0.2 m/s, the liquidity index of the spacer fluid increased between 0.5 and 0.9, the consistency coefficient increased in the range of 0.6 to 1.4 Pa⋅sn, and the stability of the spacer fluid interface decreased. However, the stability of the spacer fluid interface increased with the increase in its density in the range of 1100~1500 kg/m3. The results obtained in this study can provide a reference for selecting the operating parameters to ensure the stable operation of dual-gradient pressure systems.

Variations in cold flow and physical properties of Northern Pakistan gas condensate oil after interacting with different polymeric drilling mud systems

Variations in cold flow and physical properties of Northern Pakistan gas condensate oil after interacting with different polymeric drilling mud systems

Innovative Applications of Red Mud: Converting an Environmental Challenge to a Drilling Asset.

Red mud is generated from alumina production through bauxite digestion with caustic soda. Ma'aden aluminum production estimated the abundance in a million tons as 2.65:1:2 for bauxite, alumina, and red mud, respectively. The real challenge when it comes to red mud pertains to storage capacity; many solutions have been put forward in different industries, and in this study, the utilization of the red mud waste material is presented as a potential weighting material that could be incorporated into the design of drilling fluid systems. This study provides an assessment of the utilization of red mud as a drilling fluid, and it provides directions for the use of red mud in drilling mud systems as a filtration agent and as a finely divided solid used as a weighting material to increase the density of a given drilling fluid system. This study investigates the viability of red mud as an effective additive to drilling fluid and its effect on rheology and filtration. Different techniques are employed in red mud characterization and performance evaluation. The study assesses red mud as an inert solid in a drilling fluid system by investigating the drilling fluid rheology, apparent viscosity (AV), plastic viscosity (PV), and yield point (YP) before and after hot rolling at 150 °F, in addition to filtration properties under low-pressure, low-temperature and higher-pressure, higher-temperature conditions (at 150 °F and a differential pressure of 250 psi). Also, the study highlights the red mud solid characterization, material preparation, and acid dissolution at 150 °F. This study attempts to view the red mud situation from a practical application angle (primarily in the oil and gas industry). Test results show stable drilling mud fluid properties when utilizing red mud solid additives as weighting agents. The drilling mud exhibits relatively low plastic viscosity, gel strength, excellent sag behavior, and reasonable filtration control, even under HPHT conditions in aqueous-based fluids. The material dissolves in acid. Accordingly, red mud provides a viable option for weighting agents and filtration control.

Designing Smart drilling fluids using modified nano silica to improve drilling operations in Geothermal wells

High pressure and high temperature (HPHT) conditions in geothermal wells have necessitated the need to develop thermally stable geothermal drilling mud systems to combat potential drilling complications. This is because mud fluids degrade under HPHT conditions due to high temperature effects. This study therefore aims to establish the optimum concentration of a cationic surfactant that would successfully modify the surface of silica nanoparticles and thereafter, evaluate the performance of modified nano silica as a rheological and filtration property enhancer in water-based muds (WBMs). The surface of silica nanoparticle was successfully modified by adding Hexadecyltrimethylammonium bromide (CTAB) to silica solution. Different mud formulations containing modified nano silica with varying zeta potential values, SNP3 -S2, SNP3 -S4, SNP3 -S5, SNP3 -S6, and SNP3 -S7 with -17.7 mV, 20 mV, 28.2 mV, 35.4 mV, and 37.1 mV respectively were investigated. Results showed that modified nano silica with the highest absolute value of zeta potential enhanced drilling mud rheology as temperature increased from 149°C to 232 °C. The optimal amount of CTAB was found to be between 1.0 and 2.0 wt.%. Filtration loss was reduced by 11.4, 17.6, and 29.5% on average for mud samples SNP3-S5, SNP3-S6, and SNP3-S7, respectively, at all temperatures. Mud cake thickness was reduced by 19.9, 11.6, and 28.7% on average by mud samples SNP3-S5, SNP3-S6, and SNP3-S7 respectively at all temperatures.

Improved Water-Based Mud Rheological Properties and Shale-Inhibition Behavior by Using Aluminum Oxide and Iron Oxide Nanoparticles

Nanotechnology can be used to develop drilling fluid additives that can improve the drilling fluid's properties. Using two types of nanoparticle (NP) additives in water-based drilling fluids have been studied in this paper. Three major drilling mud systems, namely potassium chloride (KCl) as a basic mud, KCl/aluminum oxide (Al2O3) NPs, and KCl/iron (Fe2O3) NPs, were prepared and studied for enhancement of rheological properties and shale inhibition. It was found that the drilling mud contained NPs in concentrations of 0.25, 0. 5, 0.75, and 1 g. Al2O3 and Fe2O3 NPs added to KCl/polymer mud systems resulted in a 50% and 30% change in shale volume, respectively. The results demonstrated that incorporating NPs into the KCL mud system enhanced shale inhibition. Adding NPs to the KCL-WBM increased yield point, plastic viscosity, and gel strength. The COF of KCL-polymer was reduced by 48% and 34% when added Al2O3 and Fe2O3 NPs at 0.5 and 0.75g, respectively. When Al2O3 and Fe2O3 NPs were used, particularly at 1g, the amount of mud filtration decreased from 13.1ml to 8.8 ml and 8.4 ml, respectively. Overall, it was found that adding Al2O3 and Fe2O3 NPs to the KCl-WBM can improve rheological, swelling, and filtration properties as well as lubrication.

The results of laboratory testing and analysis of the use of a cationic drilling mud system in the construction of wells by sidetracking in the fields of Western Siberia

The results of laboratory testing and analysis of the use of a cationic drilling mud system in the construction of wells by sidetracking in the fields of Western Siberia

The Effect of Biopolymer Chitosan on the Rheology and Stability of Na-Bentonite Drilling Mud.

The utilization of greens resources is a grand challenge for this century. A lot of efforts are paid to substitute toxic ingredients of the conventional drilling mud system with nontoxic natural materials. In this paper, the effect of the natural polymer chitosan on the rheology and stability of sodium-bentonite drilling mud was investigated in the polymer concentration range of 0.1–3.0 wt.%. Both the shear and time dependent rheological properties of pure chitosan, pure bentonite and bentonite–chitosan dispersions were studied. Moreover, zeta potential measurements were used to evaluate the stability of bentonite-chitosan suspension. Adding chitosan improved the natural properties of drilling mud, namely: yield stress, shear thinning, and thixotropy. The viscosity of bentonite suspension increased significantly upon the addition of chitosan in the concentration range of 0.5 to 3.0 wt.% forming network structure, which can be attributed to the interactions of hydrogen bonding between -OH clusters on the bentonite surface with the NH group in the chitosan structure. On the other hand, dispersed chitosan–bentonite suspension was observed at low chitosan concentration (less than 0.5 wt.%). Increasing both bentonite and chitosan concentrations led to the flocculation of the bentonite suspension, forming a continuous gel structure that was characterized by noteworthy yield stress. The desired drilling mud rheological behavior can be obtained with less bentonite by adding chitosan polymer and the undesirable effects of high solid clay concentration can be avoided.

Optimum Selection of H2S Scavenger in Light-Weight and Heavy-Weight Water-Based Drilling Fluids.

During hydrocarbon drilling operations, the presence of hydrogen sulfide (H2S) gas could cause serious health and safety issues. Scavenging this gas and eliminating its impact are essential requirements for a safe drilling operation. This study investigated the impact of three H2S scavenger additives (copper nitrate, iron gluconate, and potassium permanganate) on water-based drilling fluids (WBDFs). The additives were tested on two actual field drilling mud samples that differ mainly in their weight. The scavengers’ impact on drilling muds was investigated by measuring their scavenging capacity and their effect on rheology, fluid loss, and pH. Potassium permanganate outperformed the other scavengers when added to the lighter (lower density) WBDF. However, it did not impact the scavenging capacity of the heavier mud system. Copper nitrate outperformed the other scavengers in the heavier drilling mud system. Also, the addition of copper nitrate in the lighter mud system increased its H2S-scavenging capacity greatly, while for iron gluconate, it did not perform very well. Overall, all the scavenger-containing drilling muds did not have any significant harmful impact on the plastic viscosity or the fluid loss properties of the drilling muds. Furthermore, all the tested drilling mud samples showed an excellent ability to clean wellbores and suspend drill cuttings evident by the high carrying capacity with the exception of iron gluconate or potassium permanganate with the heavy mud system.

Specific heat capacity of xanthan gum/PAC polymer-based drilling fluids: An experimental and correlation study

The accurate prediction of wellbore thermal profile is essential to ensure the success of any drilling operation. Currently, the heat capacity values used for predicting the thermal behavior of oil and gas wells assume the heat capacity of the drilling which leads to errors. Thus, determining the heat capacities of drilling mud systems would aid to efficiently predict the thermal distribution of wells. In this study, the heat capacities of fresh and aged mud samples of 0.8 wt% xanthan gum water-based mud and 0.8 wt% polyanionic cellulose (PAC) water-based mud and their blend system (0.4 wt% xanthan gum + 0.4 wt% PAC) were measured using a differential scanning calorimetry (DSC) from 5 to 100 °C. The new and aged samples represent testing the mud as fresh samples and over time (1–3 days). The result shows that the specific heat capacity values of the drilling muds differ from the heat capacity of water (which is generally used for drilling-related heat transfer modeling and simulations). High heat capacity values were observed for the 0.8 wt% xanthan gum mud system compared with the 0.8 wt% PAC mud system. However, the blend of 0.4 wt% xanthan gum + 0.4 wt% PAC exhibited the highest heat capacity values. In both fresh and aged samples, the heat capacity of 0.8 wt% xanthan gum mud was in the range of 3.805–4.287 J/g.oC. While 0.8 wt% PAC mud and 0.4 wt% xanthan gum + 0.4 wt% PAC mud system were within 0.7635–1.1329 J/g.oC, and 4.134–4.324 J/g.oC, respectively. These experimental heat capacity values are recommended for accurate oil & gas well heat transfer behavior modeling and simulation predictions and related studies.

Drilling waste management using zero discharge technology with Drill Cutting Re-injection (DCRI) method for environmental preservation

The energy requirement level in Indonesia is quite high. The increasing oil and gas upstream industries to fulfil energy requirement in the future is highly connected with the escalation of wastes, especially drilling wastes. Drilling is one of the main operations in upstream oil and gas industries, which can harm the environment with its various types of wastes. The drilling process produces millions of barrels of wastes each year. However, with the industries being rapidly developed to fulfil national energy requirement, environmental-related regulations for drilling activities have been firmly tightened. Drilling and drilling mud system technology is more sophisticated and the majority of oil drilling companies are starting to adopt environmentally friendly drilling options. The objective of writing this article is to acknowledge the method of drilling waste processing by considering environmentally friendly aspect. Drill Cutting Re-Injection (DCRI) is one of the developing environmentally friendly processing techniques with zero discharge in oil and gas industries. With the utilization of the DCRI process, the companies can produce positive outcomes such as low environmental impact, low safety risks, low transportation problems, and economically cleaning responsibility.

Utilizing A Dual Use Local Materials Instead of Imported Foreign Materials for Drilling Mud Conditioning

The most important constituents of drilling operation success is keeping the drillingfluid rheological properties within a certain limit to maintain continuity of theirfunctions in a good manner. To achieve that, the drilling mud system needs continuousand direct supervision such as measuring its rheological properties and treating anydeviation in their values. Viscosity is the most important property in hydraulic programsuccess due to its direct relation with a bottom hole cleaning during well drilling, thusrelated with the drilling rate, so this property should be kept essentially to ensurebottom hole cleaning and high drilling rate at the same time.Some chemicals should be added to the mud system to keep both viscosity and otherproperties within certain standards and the required limit ,the high cost of suchchemicals increase both the metric cost and the final cost of such wells.The aim of this research is to test the physical and chemical properties of a localmaterial, as a thinner and a filtration rate reducer, which tends to decrease therheological properties of drilling mud. Twenty six samples of different types of drillingmud are tested with both the local and imported foreign materials.The results for both additive materials are compared and it is found that the localthinner has the same trend as the foreign material to a certain extent. Also, in this work,the ideal rheological model is detected among six rheological models by preparing anexcel system program to determine the Average Absolute Percentage Error (AAPE).This program compares the calculated shear stress values and the measured valuesobtained from high pressure high temperature viscometer.The selected models are Bingham plastic model, Power law model, Modified powerlaw model, Robertson stiff model, and Modified Robertson stiff model and Cassonmodel.
 The most important constituents of drilling operation success is keeping the drillingfluid rheological properties within a certain limit to maintain continuity of theirfunctions in a good manner. To achieve that, the drilling mud system needs continuousand direct supervision such as measuring its rheological properties and treating anydeviation in their values. Viscosity is the most important property in hydraulic programsuccess due to its direct relation with a bottom hole cleaning during well drilling, thusrelated with the drilling rate, so this property should be kept essentially to ensurebottom hole cleaning and high drilling rate at the same time.Some chemicals should be added to the mud system to keep both viscosity and otherproperties within certain standards and the required limit ,the high cost of suchchemicals increase both the metric cost and the final cost of such wells.The aim of this research is to test the physical and chemical properties of a localmaterial, as a thinner and a filtration rate reducer, which tends to decrease therheological properties of drilling mud. Twenty six samples of different types of drillingmud are tested with both the local and imported foreign materials.The results for both additive materials are compared and it is found that the localthinner has the same trend as the foreign material to a certain extent. Also, in this work,the ideal rheological model is detected among six rheological models by preparing anexcel system program to determine the Average Absolute Percentage Error (AAPE).This program compares the calculated shear stress values and the measured valuesobtained from high pressure high temperature viscometer.The selected models are Bingham plastic model, Power law model, Modified powerlaw model, Robertson stiff model, and Modified Robertson stiff model and Cassonmodel.

A New Alternative Thinner in the Drilling Fluid System

The most important constituent of drilling operation success is keeping the drilling fluidrheological properties within a certain limit to maintain continuing their functions in a goodmanner. To achieve that, the drilling mud system needs continuous and direct supervision such asmeasuring its rheological properties and treating any deviation in their values. Viscosity is themost important property in hydraulic program success due to its direct relation with bottom holecleaning during drilling, thus related with the drilling rate, so this property should be keptbasically to ensure bottom hole cleaning and high drilling rate at the same time.Some chemicals such as thinner should be added to the mud system to keep both viscosity andother properties within certain standards and required limits; these materials have a high cost,increasing both the metric cost and the final cost of such well.The aim of this research is to test the physical and chemical properties for a local material, as athinner, which tends to decrease the rheological properties of drilling mud .Thirty nine samplesof different types of drilling mud are tested with both the native and foreign imported materials.The results for both additive materials are compared and concluded that the local thinner has thesame trend with the imported material to a certain limit.

Applications of Biodiesel in Drilling Fluids

Biodiesel, referred to as the monoalkyl ester of long-chain fatty acid ester that is synthesized by the complete transesterification of triglycerides, has captured the attention of drilling researchers attributing to its magnificent characteristics such as the high flash point, excellent lubricity, nontoxicity, high biodegradability, and abundant feedstock resources, which make it ecofriendly and technically and economically feasible for a sustainable drilling operation. There are several studies that reported and documented the usage of biodiesel in drilling fluids on laboratory and field scales. In this paper, the production and the key physical and chemical properties of biodiesel are thoroughly reviewed. Moreover, the applications of biodiesel in drilling muds either as base fluids or additives were comprehensively surveyed. The literature review revealed that the challenges of biodiesel applications in drilling mud systems are related to its chemical reactivity and adverse interactions with some additives, along with its performance deficiency at temperature above 120°C. Therefore, further investigation on temperature stability and additive compatibility is recommended. In addition, as a new approach, it is recommended to study the potentiality of using crude waste oils in drilling mud formulations. The lessons learned and recommendations stated in this paper will assist in enhancing the proved use of biodiesel and drilling fluid optimization.

Comparison of polymer-based slag-mud slurries used for drilling jobs of steam stimulated wells in the Lagunillas oilfield (Venezuela)

The mud-to-cement conversion or 'slag-mix' technology displays several advantages when compared to conventional well cementing operations. This alternative method means to combine drilling fluids, accelerators, and finely granulated slag as the hydraulic material. Steam injection is commonly used to improve crude oil production in the Lagunillas field (state of Zulia, NW Venezuela). This work compares the use of two slag-mix systems containing two polymer-based drilling muds during cementing of injection wells: an aqueous drilling fluid and an oil-in-water emulsion mud. After comparing the use of the two study drilling mud systems with a typical lignosulfonate slag-mix system, it can be stated that both systems may be suitable to be used in the application of the mentioned-above technology in steam stimulated wells. The aqueous formulations under study and a typical slag-mud slurry containing lignosulfonate show relatively similar values for most physic-mechanical properties. In contrast, the slag-mix emulsion system under consideration shows distinctive rheological and filtration behaviours compared to the other study polymer-based slag-mud slurry, but similar mechanical properties. [Received: April 26, 2019; Accepted: August 1, 2019]

Comparison of polymer-based slag-mud slurries used for drilling jobs of steam stimulated wells in the Lagunillas oilfield (Venezuela)

The mud-to-cement conversion or 'slag-mix' technology displays several advantages when compared to conventional well cementing operations. This alternative method means to combine drilling fluids, accelerators, and finely granulated slag as the hydraulic material. Steam injection is commonly used to improve crude oil production in the Lagunillas field (state of Zulia, NW Venezuela). This work compares the use of two slag-mix systems containing two polymer-based drilling muds during cementing of injection wells: an aqueous drilling fluid and an oil-in-water emulsion mud. After comparing the use of the two study drilling mud systems with a typical lignosulfonate slag-mix system, it can be stated that both systems may be suitable to be used in the application of the mentioned-above technology in steam stimulated wells. The aqueous formulations under study and a typical slag-mud slurry containing lignosulfonate show relatively similar values for most physic-mechanical properties. In contrast, the slag-mix emulsion system under consideration shows distinctive rheological and filtration behaviours compared to the other study polymer-based slag-mud slurry, but similar mechanical properties. [Received: April 26, 2019; Accepted: August 1, 2019]

Methane hydrate phase behaviour in EMIM-Cl water based mud (WBM): An experimental and modelling study

Gas hydrate sediments are known as future energy source and potential technique for the storage CO2. However, the drilling of hydrate sediments are challenged with inappropriate drilling mud systems. Ionic liquids are introduced as novel drilling mud agents that can enhance the rheology of water-based mud and at the same time manage hydrate formation risk during hydrate sediments drilling. However, the disturbances of ionic liquid water-based mud filtrate on hydrate in-situ rocks is not well understood. To achieve this, the phase behaviour of methane hydrates in 1-Ethyl-3-methy-limidazolium chloride (EMIM-Cl) water-based mud at different EMIM-Cl concentrations were measured using the isochoric T-cycle technique in a high-pressure hydrate cell within the temperatures and pressures and ranges from 273.68 – 286.10 K and 3.60 – 9.70 MPa, respectively. The rheological properties of the EMIM-Cl mud systems were tested using a TA rheometer at 271.15 K – 313.15 K. The presence of EMIM-Cl had very minimal disturbances (less than 0.5 K shift) on methane hydrate at the studied concentrations. The disturbance of EMIM-Cl of methane hydrates in pure water system is reduced by 74% in drilling mud systems. The use of EMIM-Cl at 3 wt.% could reduce the methane hydrate disturbance effect 2 times as methanol. EMIM-Cl reduced the thermal degradation of the mud by 55% at 1 wt.% with very low viscosity. The viscosity reduction of the mud occurs at lower EMIM-Cl concentrations. Suggesting that, using ionic liquids water-based mud to drill hydrate sediments will reduce the risk of releasing compacted methane gas into the borehole while drilling. In addition, an attempt is made to predict the methane hydrate equilibrium curve in the presence of the EMIM-Cl using the Dickens and Quinby-Hunt, (1997) model.

Soil chemical properties following a one‐time spent drilling mud application on native prairie

AbstractLandspraying while drilling (LWD) is an approved disposal method for water‐based drilling mud (WBM) systems in western Canada, where the mud is applied either on arable or vegetated land. This study examined the effects of a single LWD application (0, 15, 20, 40, or 80 m3 ha−1) on native prairie soil properties. Results from the study showed a significant increase in Na concentration and sodium adsorption ratio (SAR) in the 0‐ to 7.5‐cm depth. However, the highest SAR attained (3.46) after application at the 80 m3 ha−1 rate remained below levels considered detrimental to soil structure. Electrical conductivity (EC) also increased with the LWD rate but peaked at levels (447 μS cm−1 in the 0‐ to 2.5‐cm depth) much lower than the threshold for most plant species, and the effects on EC had disappeared by the end of the first year of mud application. Available P concentration (modified Kelowna method), averaged across sampling times and the two depths (0‐ to 2.5‐ and 2.5‐ to 7.5‐cm), increased from 7.4 to 11 mg kg−1 as LWD rate increased from 0 to 80 m3 ha−1. Although the available P remained at concentrations suboptimum for most crops, such concentrations may impact native prairie vegetation adapted to very low P. Drilling mud applications generally had no significant effect on available N. The application of WBM systems on the native prairie at recommended rates in western Canada may not be detrimental to soil quality and plant growth in this ecosystem.