Mud Samples Research Articles

The recovery process of the coastal mud after being sheared by external loads

In muddy coastal regions, wave-seabed interaction highly depends on the mud's rheological properties, which usually exhibit thixotropic behaviors and are closely related to the recovery of the mud. To investigate the recovery process, a series of rheological experiments were conducted on the mud samples collected from the tidal flats of the Zhoushan Archipelago. After being sheared by external loads, the mud storage modulus recovers to an equilibrium value (G∞′), and the normalized equilibrium storage modulus (G∞′/G0′) was utilized to access the structural level of the recovered mud. The effects of the magnitude, frequency, and duration of the shear load on the recovery process of the mud were investigated. Experimental results revealed thatG∞′/G0′ increases with the load magnitude and eventually reaches a constant value, regardless of the density of the mud.G∞′/G0′ is insensitive to load frequencies lower than 4 Hz when the load magnitude is below the fluidic yield stress of the mud. When load magnitude exceeds the fluidic yield stress,G∞′/G0′ decreases monotonically with frequency.G∞′/G0′ is insensitive to shear durations over O(10 s) since the internal structures were destroyed within seconds. Overall, this study offers novel insights into the rheological properties of coastal mud that provide valuable scientific support for understanding wave-mud interaction and fluid mud formation processes.

Three novel marine species of the genus Reichenbachiella exhibiting degradation of complex polysaccharides.

Three novel strains designated ABR2-5T, BKB1-1T, and WSW4-B4T belonging to the genus Reichenbachiella of the phylum Bacteroidota were isolated from algae and mud samples collected in the West Sea, Korea. All three strains were enriched for genes encoding up to 216 carbohydrate-active enzymes (CAZymes), which participate in the degradation of agar, alginate, carrageenan, laminarin, and starch. The 16S rRNA sequence similarities among the three novel isolates were 94.0%-94.7%, and against all three existing species in the genus Reichenbachiella they were 93.6%-97.2%. The genome sizes of the strains ABR2-5T, BKB1-1T, and WSW4-B4T were 5.5, 4.4, and 5.0 Mb, respectively, and the GC content ranged from 41.1%-42.0%. The average nucleotide identity and the digital DNA-DNA hybridization values of each novel strain within the isolates and all existing species in the genus Reichenbachiella were in a range of 69.2%-75.5% and 17.7-18.9%, respectively, supporting the creation of three new species. The three novel strains exhibited a distinctive fatty acid profile characterized by elevated levels of iso-C15:0 (37.7%-47.4%) and C16:1 ω5c (14.4%-22.9%). Specifically, strain ABR2-5T displayed an additional higher proportion of C16:0 (13.0%). The polar lipids were phosphatidylethanolamine, unidentified lipids, aminolipids, and glycolipids. Menaquinone-7 was identified as the respiratory quinone of the isolates. A comparative genome analysis was performed using the KEGG, RAST, antiSMASH, CRISPRCasFinder, dbCAN, and dbCAN-PUL servers and CRISPRcasIdentifier software. The results revealed that the isolates harbored many key genes involved in central metabolism for the synthesis of essential amino acids and vitamins, hydrolytic enzymes, carotenoid pigments, and antimicrobial compounds. The KEGG analysis showed that the three isolates possessed a complete pathway of dissimilatory nitrate reduction to ammonium (DNRA), which is involved in the conservation of bioavailable nitrogen within the ecosystem. Moreover, all the strains possessed genes that participated in the metabolism of heavy metals, including arsenic, copper, cobalt, ferrous, and manganese. All three isolated strains contain the class 2 type II subtype C1 CRISPR-Cas system in their genomes. The distinguished phenotypic, chemotaxonomic, and genomic characteristics led us to propose that the three strains represent three novel species in the genus Reichenbachiella: R. ulvae sp. nov. (ABR2-5T = KCTC 82990T = JCM 35839T), R. agarivorans sp. nov. (BKB1-1T = KCTC 82964T = JCM 35840T), and R. carrageenanivorans sp. nov. (WSW4-B4T = KCTC 82706T = JCM 35841T).

Analysis of a drilling mud-based system on the common problems related to coiled tubing application in slim-hole oil wells

Coil tubing is slim and looks like a long, continuous length of pipe made from carbon steel metal that is a lesion on spool that is 1 to 3.25 inches in diameter of 26,000 feet long. The main benefit of coil tubing in drilling operations over wireline jobs is the ability to pump chemicals through the coil and the ability to push it into the hole rather than relying on gravity. Inappropriate selection of the drilling mud is one of the contributing factors to hole problems. Different experiments were conducted to determine the mud rheology of multiple mud samples. Certain parameters, like the critical velocity, are calculated using a numerical approach for the coiled tubing applications. In addition, it is crucial to determine the pump pressure required to maintain a specific flow rate. It is noted that drilling operations become more efficient at lower plastic viscosities; however, plastic viscosity is reduced through dilution; hence, the rate of penetration is improved. Moreover, a higher yield point is capable of transporting the cuttings more effectively than a lower yield point. The critical velocity indicated the boundaries between the laminar and turbulent flow regimes. As the mud flow rate inside the tubing increased, the velocity increased, causing the shear stress at the tubing wall to increase.

The Influence of Oscillatory Frequency on the Structural Breakup and Recovery of Coastal Mud

The structural breakup and recovery of coastal mud are closely related to wave propagation, mud transportation, and coastal morphology evolution. Due to the influence of climate, topography, and other factors, the wave frequency in marine environments is more variable than fixed. To investigate the mud structural breakup and recovery process under oscillatory shear loads with different frequencies, a series of oscillatory rheological experiments of the coastal mud collected from the tidal flats of Zhairuoshan Island, Zhejiang province, China, were carried out. The results revealed that the structural breakup of coastal mud had a two-step transition process. The fluidization occurs more rapidly at higher frequencies, but the influence of frequency on the two yield stresses is limited. In addition, frequency has a complex effect on the structural recovery of coastal mud. The normalized equilibrium storage modulus (G∞′/G0′) does not change monotonically with frequency. Moreover, the viscosity quickly approaches equilibrium when a shear load is applied. After that, when a low-frequency load is applied, G∞′/G0′ is no longer related to the pre-shear duration. However, when a high-frequency load is applied, G∞′/G0′ of the mud sample pre-sheared for 500 s is significantly larger than that of the sample pre-sheared to the minimum viscosity. This study is anticipated to provide reference and supplementary test data for understanding the interaction between waves of different frequencies and muddy seabed.

Experimental Study on Dynamic Barite Sag and Effects of Inclination and Pipe Rotation

Summary Barite sag causes pressure fluctuations in the wellbore, which is undesirable. These problems usually occur with oil-based muds (OBMs; invert emulsion muds) and are associated with fluid properties and operation parameters. Drilling issues related to this undesirable phenomenon include wellbore instability, lost circulation, and stuck pipes. As barite sagging is a complex phenomenon, the mechanisms that cause and aggravate it still need to be fully understood to mitigate these problems. This study examines barite sagging in the wellbore with inner pipe rotation to understand the process and develop prevention strategies. Thus, a flow loop study with OBM is conducted in a concentric annular test section with varying inner pipe rotation and inclination angles. The tests were performed at an elevated temperature (49°C) to simulate borehole conditions. By measuring the pressure profile in a mud sample trapped in the test section, barite sagging was evaluated. Using the data, we calculated the density difference between the top and bottom sections of the column. The novelty of the work lies in continuous monitoring of the density profile of the mud column, which is sheared between two coaxial cylinders to simulate drillstring rotation in the wellbore, and utilizing the data for evaluating barite sag. The results show the evolution of the pressure profile with time, indicating the sagging of barite particles at the bottom of the test section. Due to barite sagging, the density of the top portion of the mud column decreased over time, while the density of the bottom part increased. The lateral sedimentation of barite particles toward the annulus outer wall enhances barite sag in inclined configurations. The sedimentation creates two suspension layers with different densities, leading to secondary flow, which enhances sagging. Hence, the primary factor driving barite sagging is inclination. An increase in inclination angle from 0° to 50° resulted in a significant (more than twofold) increase in mud density difference. Also, the rotation of the pipe delayed sagging during the early phases of the testing process (less than 20 minutes). However, it did not have much effect as the sagging progressed, resulting in approximately the same density difference in both cases (i.e., with and without rotation).

Development of a Low-Molecular-Weight Filtrate Reducer with High-Temperature Resistance for Drilling Fluid Gel System.

Currently, conventional polymeric filtrate reducers with high-temperature resistance for use in drilling fluids have high molecular weights, which greatly affects the rheological properties. Therefore, to address the challenges in regulating the rheology and filtration performance of high-density drilling fluids at high temperatures, it is essential to develop low-molecular-weight filtrate reducers with high-temperature resistance. In this study, a low-molecular-weight filtrate reducer with high-temperature resistance (LMF) was prepared via free radical polymerization from acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid as monomers, tertiary dodecyl mercaptan as a chain transfer agent, and ammonium persulfate as the initiator. LMF was then characterized by infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography. The obtained filtrate reducer exhibits a weight-average molecular weight (Mw) of 3819 and an initial thermal decomposition temperature of 300.7 °C, indicating good thermal stability. The effects of LMF dosage, temperature, and NaCl dosage on the rheology and filtration performance of mud samples were also investigated, and the mechanism of action was revealed by zeta potential, particle size distribution, scanning electron microscopy, and adsorption measurements. The results reveal that LMF increases the mud sample viscosity and reduces its filtration. For example, the filtration of the mud sample with 2 wt% LMF was 7.2 mL, a reduction of 70% compared to that of a blank mud sample. Further, after aging at 210 °C for 16 h, the filtration of the same sample was 11.6 mL, and that of a mud sample with 2 wt% LMF and 35 wt% NaCl after aging at 180 °C for 16 h was 22 mL. Overall, we have reported a scheme to prepare a low-molecular-weight filtrate reducer with high-temperature resistance and superior filtrate-reducing effects, laying the foundation for the investigation and development of low-molecular-weight filtrate reducers.

Experimental investigation of multiple industrial wastes for carbon dioxide removal strategies

Industrial solid waste by-products are being increasingly employed for geochemical carbon dioxide removal (CDR) strategies due to their fine grain size, accessibility, and large annual production tonnages. Here, a range of such by-products has been tested experimentally for their reactivities with CO2 and water. Sample solutions were monitored for 100 h for changes in chemistry, and solid samples were characterised pre- and post-experiment. Samples rich in Ca- and Mg-bearing minerals, such as dunite, kimberlite, and ilmenite mine tailings, as well as marble quarry cuttings, were key cation sources. Ni sulphide, fluorite and borax tailings, coal-fired power plant fly ashes, and red mud samples showed high dissolution rates. The highest reaction rates were often observed during the initial few hours, and compared well to rates determined for rocks typically targeted for CDR purposes, such as basalt and gabbro. Several samples also showed secondary carbonate precipitation, suggesting opportunities for the development of single-step CDR technologies. Overall, the results of this study indicate that several industrial by-products can provide sufficient cations at favourable dissolution rates for geochemical CDR purposes. Any on-site or near-site conditions for reaction acceleration such as heat, concentrated CO2 or microbes, could further increase favourability for geochemical CDR opportunities.

Rare Earth Element Characterization of Bledug Kuwu Mud Volcano, Central Java, Indonesia, based on Geochemical Analyzes (Susceptibility, XRF, XRD, SEM-EDS and ICP-EOS)

Mud volcano material is generally rich in oxides, while oxides are the main compounds forming rare earth elements. Bledug Kuwu, Central Java, Indonesia, is one of the active mud volcanoes, so there may be rare earth elements. This research is the characterization of rare earth elements (REE) in the Bledug Kuwu mud using magnetic and geochemical methods. Magnetic characterization uses magnetic susceptibility measurements. The geochemical characterization of the mud samples consisted of the XRF (X-Ray Fluorescence), XRD (X-Ray Diffraction), ICP-EOS (inductively coupled plasma) test, and the SEM-EDS (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy) test. The results of the geochemical analysis of the Bledug Kuwu mud sample were the content of quartz, kaolinite, and calcite with an average concentration of 42.26%, 23.67%, and 33.96%. The susceptibility of Kuwu's mud is 0 because the concentration of metal elements is low; according to the results of XRF, XRD, and SEM tests identified the main mud elements as C, O, Si, Ca, and Al. The rare earth elements in Kuwu's mud are Ce, Dy, Eu, Gd, Ho, La, Nd, Pr, Sm, Tb, Y, and Sc. The highest concentrations were Ce 52.22 ppm and La 47.95 ppm.

Modified locally derived graphene nanoplatelets for enhanced rheological, filtration and lubricity characteristics of water-based drilling fluids

Drilling fluid rheology, filtration, and lubricity are fundamental parameters that influence the efficiency and ease of drilling operations. The drilling industry is constantly exploring different research areas for stabilizing and improving these parameters at high temperatures. The use of drilling fluid additives, especially synthetic polymers, poses a threat to the environment. Herein, rice husk char (RHC) was used to synthesize graphene Nanoplatelets (GNP) whose surface is modified with triton-X100 nonionic surfactant. Field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), Particle size distribution (PSD), Energy Dispersive X-Ray Analysis (EDX), and Zeta potential analysis are performed on the synthesized nanomaterials to verify their morphology, functional groups, particle size, elemental composition, and material stability. Synthesized GNP from RHC (GNP-RHC) along with surface-modified GNP-RHC (GNP-TXT) were examined critically and their properties compared using a water-based mud (WBM) formulation. The rheological and lubricity characteristics of all the mud samples were determined before and after hot rolling (AHR), and the filtration properties were determined under API and high pressure high temperature (HPHT) conditions. The TGA results indicate that GNP-TXT nanomaterial resists thermal degradation with 10% weight loss at 300 °C, while the zeta potential analysis indicates the materials are stable. Since the GNP-TXT particles are so well dispersed, the GNP-TXT-based muds worked better than the GNP-RHC-based muds and was more stable at controlling filtration and improving rheological properties. For example, at 1.5 g AHR, the plastic viscosity of GNP-TXT-based mud decreased by 22.2% from 9 to 7 cP, while that of GNP-RHC-based mud decreased from 17 to 7 cP by 59%. Also, the API and HPHT FL of WBM of 11 and 24.8 mL, respectively, were reduced by GNP-TXT-based muds to the range of 8.6 and 9.8 mL for API and 18.6 and 22.3 mL for HPHT. However, GNP-RHC-based drilling muds showed a lower fluid loss control of the WBM between 9.6 and 10.2 mL for API and between 19.6 and 23.6 mL for HPHT. Furthermore, the coefficient of friction of the WBM of 0.45 was decreased with GNP-RHC concentrations between 0.47 and 0.32, while GNP-TXT demonstrated a higher decrease between 0.26 and 0.20.

Investigating the suitability of North Dakota fly ash as fluid loss reducing additive in densified water-based drilling fluid

Fluid loss circulation control during drilling operations is becoming more challenging as exploration moves from conventional to unconventional energy resources. The process of controlling filtrate loss during drilling operation necessitates the right design of drilling fluid that is capable to build an impermeable thin filter cake layer and permit a loss of a reasonable amount of filtrate volume into the formation. It is essential to understand the dynamics that play out between particle morphology of drilling mud additives to assess the sealing efficiency of the loss-reducing additives. As a result, a lot of materials were suggested as fluid loss-reducing materials, which also give thin filter cake thickness. This study investigates the suitability of a coal-fired plant waste (fly ash), as an alternative supplement for filtration agents to improve the quality of the filter cake layer that is built using ilmenite (FeTiO3) derived densified drilling fluid. The ilmenite-derived densified water-based mud samples containing 0, 1, 2, and 3 lb./bbl of fly ash were investigated. To gain an understanding of the pozzolanic influence of class C fly ash on ilmenite-weighted water-based mud, tests were conducted at reservoir conditions according to API specifications. The results from drilling fluid tests were benchmarked against the API standard range of values and contrasted with a control drilling fluid with no-fly ash added. It has been found that mud samples that include fly ash have better filtration properties. The openings in the filter cake were sealed by the amorphous structured fly ash particles, which created an impermeable filter cake. In Mud-4 and Mud-5, where the filtrate volume was reduced by 75% and 79%, respectively, the influence of particle size distribution to form a good sealant and a further reduction in filtrate loss was observed.

Production, Characterization and Application of a Novel Chitosanase from Marine Bacterium Bacillus paramycoides BP-N07.

Chitooligosaccharides (COS), a high-value chitosan derivative, have many applications in food, pharmaceuticals, cosmetics and agriculture owing to their unique biological activities. Chitosanase, which catalyzes the hydrolysis of chitosan, can cleave β-1,4 linkages to produce COS. In this study, a chitosanase-producing Bacillus paramycoides BP-N07 was isolated from marine mud samples. The chitosanase enzyme (BpCSN) activity was 2648.66 ± 20.45 U/mL at 52 h and was able to effectively degrade chitosan. The molecular weight of purified BpCSN was approximately 37 kDa. The yield and enzyme activity of BpCSN were 0.41 mg/mL and 8133.17 ± 47.83 U/mg, respectively. The optimum temperature and pH of BpCSN were 50 °C and 6.0, respectively. The results of the high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) of chitosan treated with BpCSN for 3 h showed that it is an endo-chitosanase, and the main degradation products were chitobiose, chitotriose and chitotetraose. BpCSN was used for the preparation of oligosaccharides: 1.0 mg enzyme converted 10.0 g chitosan with 2% acetic acid into oligosaccharides in 3 h at 50 °C. In summary, this paper reports that BpCSN has wide adaptability to temperature and pH and high activity for hydrolyzing chitosan substrates. Thus, BpCSN is a chitosan decomposer that can be used for producing chitooligosaccharides industrially.

Suppressive effects of geotextiles on soil water evaporation

Geotextiles find wide applications in the field for filtration and drainage. When applied on the soil surface they influence soil evaporation. The objective of this work is twofold: (a) to assess the effectiveness of four different geotextiles as cover materials on soil evaporation, (b) to study the combined effect of geotextile and perforated mechanical barriers on soil evaporation. The first set of experimental programs consisted of three soil samples i.e. kaolin, dredged mud from the port of Brisbane and a locally obtained red mud sample from Queensland, Australia tested with four types of non-woven geotextiles under four controlled climatic conditions. All the 4 geotextiles had suppression effects on soil evaporation to degrees that varied with the type of soil, ratio of pore size to thickness of geotextiles (M*), product of pore size to thickness of the geotextiles (N*) and climatic conditions. Geotextiles with a higher pore size (O95) and M* allowed water vapor to move through relatively easily leading to higher evaporation rates. Geotextile with a higher thickness and N* value provided a higher suppression effect on soil evaporation. In a recently introduced dewatering method involving perforated ventilated well method, evaporation from soil take place through geotextiles and the perforated well. Mimicking this, impacts on soil evaporation with geotextiles sandwiched between soil sample and perforated sections were also studied. Maintaining similar number and arrangement of the perforations, soil evaporation was noted to be higher with rectangular shaped perforation compared to circular shaped perforations.

Surface Geology Analysis on the Relationship between Fault Creep and Overpressure in Grobogan, Central Java, Indonesia

The Grobogan Regency is a significant location for oil and gas exploration due to its proximity to active oil and gas fields. Geologically, this area is intersected by the Kendeng thrust fault and exhibits several surface manifestations of mud volcanoes near the fault. However, there have been limited studies examining the activity of the Kendeng thrust fault and its relationship to overpressure and earthquakes, which could affect oil and gas exploration and natural disaster mitigation in the region. This paper focuses on utilizing surface geological mapping data and Interferometric Synthetic Aperture Radar (InSAR) data to analyze the relationship between fault creep and overpressure manifestations in Grobogan, Central Java. While continuous research on fault creep has been conducted since the 1960s on the San Andreas fault in the United States, there has been a lack of continuous research on onshore fault creep in the Northeast Java Basin or Kendeng Basin, particularly in the Grobogan area. This region, known for its abundance of active mud volcano manifestations, is predominantly characterized by marl and clay lithology. It represents a warm basin environment that is prone to overpressure and ideal for fault creep occurrences.To investigate further, fluid, gas, and mud samples were collected from the mud volcanoes, along with rock samples from the surrounding area, for comprehensive laboratory analysis. The integration of these sample analyses aimed to determine the correlation between the activity of the Kendeng thrust fault creep and the subsurface overpressure conditions. While this study observed several indications of creeping in the vicinity of InSAR anomalies, the exact location of the creeping fault plane could not be definitively determined. The Kendeng thrust fault exhibits the three main factors necessary for initiating fault creeping. The fault segment’s extremely slow creeping may be linked to the activity of the mud volcanoes, as indicated by the results of fluid, gas, and rock sample analysis. The findings of this research hold potential for informing the development of oil and gas fields, as well as enhancing the mitigation of natural disasters associated with oil and gas exploration and earthquakes in the region.

ANALYSIS OF MUD DENSITY BY USING CUTTING CAPACITY ANNULUS METHOD

Drilling mud has an important role in drilling operations, as well as lifting the cutting to the surface, controlling the pressure of the formation, and preventing the collapse of the borehole. Therefore, the drilling operations can be continued without obstacles. The function of the drilling mud depends on the conditions of the formation to be drilled for optimal results. One of the main functions is to lift cutting from a bottom hole to the surface. In the annulus, the minimum speed for lifting the cutting to the surface was calculated. The Cutting Capacity Annulus (CCA) is the value of the level of solids in the annulus. The proper concentration of cutting in the annulus is not more than 5%, to avoid drilling problems, such as decreased rate of penetration (ROP), increased drag and torque, and stuck pipe related to hole cleaning problems. In analyzing the lifting ability of cutting, CCA is very suitable to be used because it accounts for the parameters of ROP value. This study conducted a comparison of two types of natural polymers that have a function to help the hole cleaning in the drilling process. The two types of polymers are cellulose polymers (drispac) and polysaccharide polymers (starch). Furthermore, it also had been tested on a field scale using the cutting transport ratio (CTR) method to find out how much ratio is obtained in the two types of polymer mud. Based on the test of the two mud samples on the cutting removal process in the CCA method at a temperature of 150oF, the mud samples containing starch ranged from 1.0731% to 1.0792%, while the mud samples containing drispac ranged from 1.0730% to 1.0793%. At 200oF the mud samples containing starch ranged from 0.7357% to 1.3604%, while the mud samples containing drispac ranged from 0.7357% to 1.3603%. At a temperature of 250oF, the mud samples containing starch ranged from 0.2652% to 0.4903%, while the mud samples containing drispac ranged from 0.265178% to 0.4907%. Although the density of the starch-containing mud sample was greater than drispac, the CCA value did not have much effect due to the difference in density of the two mud samples of 0.1 ppg. Both samples were able to optimally lift the cutting above the surface because the CCA value was less than 5%.

Analysis of heavy metal accumulation and environmental indicators in fluids and drilling cuttings

Heavy metal pollution caused by oil well drilling operations is one of the environmental problems that the oil industry imposes on the environment. The source of such pollution should first be determined precisely to manage and control it. Studies show that the main source of environmental pollution in well drilling operations is the drilling fluid additives or the elements in the well column formations. In this research, in addition to measuring the concentration of heavy metals and comparing it with the existing standards, an attempt is made to determine the exact origin of these metals. To study the source of such pollution in the area of the Abteymour oil field in the southwest of Iran, 19 cuttings (from 8 formations), 10 waste samples (drilling mud and cutting), and 7 drilling muds and their additive samples from one of the wells were assessed to determine the concentration of heavy metals. In this study, a total of 56 elements were measured using the ICP-MS analysis method; however, 16 elements that had a higher concentration than the average of the upper crust (as a reference concentration) with Ni, Cr, and V elements were studied. These 16 elements included Fe, Ag, As, Ba, Bi, Cd, Cu, Mg, Mn, Mo, Pb, Sb, Sr, and W heavy metals, and Ca and S elements. The analysis of the examined elements' concentrations in muds and their additives revealed that samples of heavy water-based muds and barite contained the highest concentrations of the elements. The cuttings samples primarily had a higher concentration than the waste samples, which was due to the mixing of the cuttings of different depths in the waste and the dilution of the element concentration in the waste samples, according to an analysis of the variation of 19 elements compared to the depth. Among the studied formations, the Gachsaran Evaporite Formation has high concentrations of studied elements. This problem is due to the complexity of the lithology of Gachsaran Formation, which consists of all kinds of rocks such as anhydrite, gypsum, salt and marl. This result shows the importance of managing drilling operations in this formation to prevent the release of heavy metals in the environment. Based on the Igeo, Ca, Ag, As, Ba, Bi, Cd, Cu, S, Sb, and Sr elements had high levels of pollution in all samples of waste and drilling cuttings. Based on the EF, only Cr, Mn, and V elements had no enrichment, and other elements had different enrichment levels in waste and drilling cuttings samples. The main result of this study shows that the main source of heavy metal pollution in the first stage is the type of elements in the lithology of the well column formations and in the next stage is the type and additives of the drilling fluid used in the well. Specifically, in the Abteymour oil field, the main reason for the contamination of the Gachsaran formation is due to the complexity of the lithology and the use of heavy water base drilling mud. The results of this research show that before choosing the type of drilling fluid, it is necessary to do a detailed environmental study and identify heavy elements in subsurface formations and the designed drilling fluid.

Fly ash as an additive for controlling sagging tendency in ilmenite densified water-based mud for a highly inclined high temperature well

Sagging has a detrimental outturn on the drilling effectuation and increases the drilling risks. Drilling deviated wells and wells with high pressures and temperatures has a greater impact on the sagging occurrence. It is desirable for a drilling operator to ensure stability and maintain the suspension of weight material in the fluid throughout the drilling operation. Optimum drilling fluid design for the drilling industry aids in the effective removal of cuttings and suspension of cuttings to avoid expensive complications and maintain the stability of the well particularly for drilling highly deviated wells and wells in high-temperature harsh formations. Drilling fluid physio-chemical behavior changes because of the weighing agent separating from the liquid phase and settling down, which is referred to as sagging and is more prevalent in highly inclined wells and wells with high temperatures. Few studies are geared toward understanding and possibly mitigating the occurrence of solid sagging to improve the drilling performance, particularly in highly deviated wells and wells in high-temperature harsh formations. This study evaluates the effectiveness of fly ash buffered with an industrial standard polymer to eliminate ilmenite sag encountered with water-based drilling fluids at high-pressure high-temperature (HPHT)environments when accessing geothermal wells, extended-reach wells, and high-inclined wells. Four laboratory barrels of water-based drilling fluids were formulated for this study. Fly ash of 130 μm particle size was added to mud samples at 0, 1, 2, and 3 lb./bbl ratio. Each industrial standard polymer of 1lb./bbl was added to all four samples prepared. The influence of fly ash on drilling fluids properties was thoroughly evaluated by measuring static and dynamic sagging at vertical and inclined (300, 450, 600, 700, 800, and 900) conditions over a range of temperatures (2500F, 3000F, 3500F, and 4000F). It was observed that the inclusion of fly ash improves the sagging phenomena and the rheological behavior of the water-based mud samples to satisfy the industrial API standard value.

Comparative study of bentonite and Ikwo clay for oil-based drilling mud formulation

As the demand for energy rises, drilling activities and the use of drilling mud by oil and gas industries keep increasing, leading to large consumption and high importation cost of drilling mud materials. The study is conducted to replace high cost of drilling mud materials (bentonite) which is a burden on the companies and our economy at large, with respect to foreign exchange challenge. Locally sourced drilling mud material, clay precisely, from Ebonyi State, particularly Ikwo clay, is yet to be explored as alternative to commercial bentonite. The specific objective of this study is to analyse and compare Ikwo clay in replacement to commercial bentonite as viscosifiers for formulating oil-based drilling mud. The driving motivation is to utilize local content (Ikwo clay) which is in abundance and has remained unprocessed substitute for bentonite. The clay undergoes activation using sulfuric acid (H2SO4) following conventional procedures. XRF spectrophotometers determine chemical compositions and functional groups of bentonite and clay samples. Oil-based muds are separately formulated using bentonite and Ikwo clay additives. The mud weight, pH, apparent viscosity, plastic viscosity, yield point, and gel strength of the respective muds are evaluated. The interactive effects of the process variable on viscosities of each mud sample are determined, and the viscosity of the respective muds was optimized using the Central Composite Design (CCD) tool of Design Expert software (version 12) based on RSM. Activation of the local clay improved its properties, as results of the chemical composition revealed that Ikwo clay contains exchangeable cation like potassium ion (K+)) and an essential metal (iron (iii) ion (Fe3+)), with the presence of alumina signifying its suitability in terms of plasticity and swelling ability. The Ikwo clay mud had a higher sample mud weight than the bentonite mud, which indicates that Ikwo clay can manage formation pressure and improve wellbore stability. The optimum viscosities of the oil-based muds with bentonite and Ikwo clay additives are obtained at 15.49 cP and 18.82 cP, respectively. The optimum values are realized at a bentonite/Ikwo clay dosage of 8 wt%, a temperature of 313 K and a mixing time of 35 min. The novelty of Ikwo clay compared to imported bentonite is its ability to offer structural stability to drilling mud (Rana et al., 2020). This feature is used to control wellbore instability during drilling operations. Ikwo clay is a good fit for bentonite replacement as a viscosifier in formulating drilling mud.

Microbial-assisted extraction of bentonite from waste drilling fluid: A sustainable approach for waste management

Bentonite is an important component of water-based drilling mud, giving it important rheological properties. However, the drilling mud becomes contaminated with petroleum hydrocarbons when it comes to the surface from greater depths, making the bentonite unsuitable for reuse in drilling operations. As a result, polluted drilling mud is frequently disposed of in landfills without being treated. This paper presents an eco-friendly solution that does not require external energy, promotes sustainable reuse of drill fluids and materials, and is cost-effective to treat the contaminated bentonite so it can be used again in the drilling process. The primary aim of the study was to assess the capacity of naturally occurring microorganisms found at different depths within an oil well to degrade crude oil and extract bentonite that had been contaminated by petroleum hydrocarbons. For that, samples of waste drilling mud of 400, 800, 1200, 1600, and 1682 m depth were collected from one central PSU. Isolation and screening were done for all the depths, and one isolate from 1682m showed the highest degradation efficiency (64% at 7 days) by gravimetric analysis and was identified as Pseudomonas stutzeri based on nucleotide homology and phylogenetic analysis. This bacterial culture was used to extract bentonite from drilling mud in a 1:1 proportion, and the extracted bentonite was analysed using FT-IR. Also, a comparative study was conducted to assess the impact of hydrocarbon contamination on Atterberg's limits and specific gravity of the bentonite.

Yeast diversity in pit mud and related volatile compounds in fermented grains of chinese strong-flavour liquor

Chinese strong-flavour liquor is produced via a traditional solid-state fermentation strategy facilitated by live microorganisms in pit mud-based cellars. For the present analysis, pit mud samples from different spatial locations within fermentation cellars were collected, and the yeast communities therein were assessed via culture-based and denaturing gradient gel electrophoresis (DGGE) approaches. These analyses revealed significant differences in the composition of yeast communities present in different layers of pit mud. In total, 29 different yeast species were detected, and principal component analyses revealed clear differences in microbial diversity in pit mud samples taken from different cellar locations. Culture-dependent strategies similarly detected 20 different yeast species in these samples. However, while Geotrichum silvicola, Torulaspora delbrueckii, Hanseniaspora uvarum, Saturnispora silvae, Issatchenkia orientalis, Candida mucifera, Kazachstania barnettii, Cyberlindnera jadinii, Hanseniaspora spp., Alternaria tenuissima, Cryptococcus laurentii, Metschnikowia spp., and Rhodotorula dairenensis were detected via a PCR-DGGE approach, they were not detectable in culture-dependent analyses. In contrast, culture-based approaches led to the identification of Schizosaccharomyces pombe and Debaryomyces hansenii in these pit mud samples, whereas they were not detected using DGGE fingerprints profiles. An additional HS-SPME-GC-MS-based analysis of the volatile compounds present in fermented grains samples led to the identification of 66 such compounds, with the highest levels of volatile acids, esters, and alcohols being detected in fermented grains from lower layer samples. A canonical correspondence analysis (CCA) suggested they were significant correlations between pit mud yeast communities and associated volatile compounds in fermented grains.

Sound Isolation Performance Assessment of Traditional and Retrofitted Timber-Framed Dwellings

This study focuses on sound isolation performances of original timber-framed interior wall and floor components in traditional-framed dwellings in Turkey and 19th century mud-brick samples used as infill within the timber frame. The acoustical ramifications of some retrofits proposed in the contexts of minimum intervention and refunctioning the traditional dwellings are assessed in reference to the relevant standards. Field measurements show that sound isolation performances of the original timber-framed wall and floor are ineffective. The results of this study show that acoustical retrofits applied on the original wall keeping its wood lath and mud-brick infill are about 5–7 dB in the weighted sound reduction index (RW) and are more effective than those applied on the reconstructed wall. Sound transmission loss values of 50- and 100-mm-thick authentic mud samples are 22–38 and 30–43 dB, respectively, between 125 and 4,000 Hz. The sound absorption coefficient at mid frequencies and the noise reduction coefficient of 50-mm-thick mud samples are 0.28 and 0.23, respectively. These results signal the importance of keeping traditional construction techniques of wall and floor during retrofits to improve the sound isolation performance. Adobe mixtures similar to the 19th-century mud-bricks can be of guidance for the production of innovative soundproofing earth-based building materials.