Barite Particle Research Articles

Analysis of uneven density of oil-based drilling fluid caused by shale respiration

Longmaxi shale formation has developed beddings and fractures in southern Sichuan, which is prone to well leakage and wellbore instability. In the drilling process of horizontal section of Ning 209H58-2 well, drilling fluid would loss during circulation and return after pump stopped in the same section, which was the obviously respiration effect. The larger amount of leakage and pumping back, the greater the difference of drilling fluid density would be, accompanied by the increasing value of the gas. In this paper, shale was determined to have “screen effect” by assuming methods, the drilling fluid would loss as the equivalent circulating density was greater than the crack opening pressure, and the crack width was just in the size range of barite particle, then the larger size barite cannot enter in shale cracks end gathered together, and low density drilling fluid would penetrated into the formation, and then the drilling fluid density would be high in the first and low then after circulation again. The equivalent circulating density would be controlled by reducing the drilling fluid density, the effects of microfracture opening and respiration would be avoided, and the drilling fluid density would return to normal after circulation. This paper illustrates that the shale screen effect was the main reason for the uneven density of drilling fluid, which was expected to provide technical support for the development of horizontal shale gas Wells.

Experimental and modeling studies on dynamic barite sag and effects of particle size, shear rate, and fluid rheology

Barite is often utilized to control the weight of drilling muds. However, in inclined wellbores, barite particles settle out of the mud in a lateral direction and quickly reach the wellbore wall. Over time, deposited particles form unstable barite beds that slide intermittently downward, causing downhole pressure fluctuations. The observation is often referred to as barite sag, which occurs prominently when the system is in a dynamic state. Barite sag leads to density variation in the mud system, resulting in drilling issues such as stuck pipe, fluid loss and lost circulation, loss of well control, and wellbore instability. Various experimental studies have been conducted on barite sag, but limited mathematical modeling has been undertaken.This article presents the results of experimental and mathematical modeling studies on barite sag. First, particle size distribution tests were performed with API barite. Then, different oil-based muds (OBMs) were prepared using barite samples with various particle size distributions. Next, the apparent viscosities of the muds were measured with a rheometer. Then, the Viscometer Sag Shoe Test (VSST) method was used to study barite sag at 49 °C varying rotational speed and barite particle size distribution. Furthermore, the settling behavior of barite particles under dynamic conditions was simulated using a sedimentation-consolidation model. The model is solved numerically by applying a fully implicit finite difference method. The accuracy of the numerical solution is validated using simulation results presented in a previous study. The model has been improved to handle non-Newtonian fluids and simulate dynamic conditions.According to the apparent viscosity measurements, barite particle size has a minor effect on OBM rheology. The VSST results also show that barite sag increases with particle size and rotational speed. The improved model predicts VSST results fairly well. Additionally, a model-based parametric study indicates that barite sag decreases with increasing OBM rheological parameters (consistency index, yield stress, and fluid behavior index).

Mineralogical and granulo-chemical characterization of veins 4 and 10, of Ain Mimoun baryte ore mine

Purpose. The purpose of the carried out granulo-chemical and mineralogical study, realised on barite of two veins 4 and 10 of Ain Mimoun deposit (Algeria), is the identification of the barite ore in order to be able to choose a reliable processing method due to its complicated structure. Methodology. The investigation was carried out by X-Ray Diffractions (XRD), Scanning Electron Microscope (SEM), X-Ray Fluorescence (XRF), particle size analysis and microscopic observations. Findings. Using the investigation devices, predominance of barite minerals was found at 51%, quartz in the vicinity of 34% and calcite at 9%, with a homogeneous distribution in all the fractions observed. Adding to that, the main compounds (oxides) present are SiO2, CaO, Fe2O3, Al2O3, P2O5, Na2O, K2O, TiO2, and MnO. Originality. For the first time the characterization of veins 4 and 10, in which the barite particles are embedded in silica, has been realised for the purpose of proving the possibility of their processing. Practical value. The obtained results confirm, on the one hand, that veins 4 and 10 are rich in barite and, on the other hand, barite particle release from silica particles is possible. Thus, we suggest, for a better and diversified use of the ore of the veins in question, the application of the flotation process, since the latter makes it possible to obtain high-quality concentrates, so it can be used not only in the petroleum field but also in the pharmaceutical and other industries.

Formation of marine barite in the deep-sea environment: Evidence from sinking particles in the challenger deep, Mariana Trench

A description of the morphology and an understanding of the formation processes of barite in deep waters are lacking. Sinking particles were sampled in a water column at 2000 m, 4000 m and 6000 m in 2016 in the Challenger Deep, Mariana Trench. Sinking barite (BaSO4) crystal particles at different depths and seasons were systematically observed by scanning electron microscopy (SEM), and the chemical composition was determined by energy dispersive X-ray spectrometry (EDS) and inductively coupled plasma mass spectrometry (ICP-MS). The barite particle size ranges from 1 to 6μm, and most of the barite particles exhibit good crystal shape, and are in the initial phase of nucleation. The crystal morphologies were mainly ovoid, followed by rounded, hexagons and polyhedrons. The complete shapes of barite under direct observation by SEM show that they mostly formed in the deep-sea environment. The new findings of this paper provide direct microscopic evidence for the two previous views that diatoms and extracellular polymeric substances (EPS) play an important mediating role in barite precipitation. Affected by the funneling effect of the trench, the barite content in sinking particles increases with depth. The East Asian winter monsoon brings large amounts of Asian dust into the ocean in March, this can promote the growth of diatoms and other marine organisms, and thus make the content of barite in March higher than that in August.

Effects of barite size on the fluorite flotation using the reagent scheme of GS/NaOl

Barite is easily ground to slime fraction, which may affect the fluorite flotation. The role of barite particle size in the fluorite flotation was studied in this work. Single mineral flotation showed that gelatinized starch (GS) selectively depressed the barite flotation with different size fractions while it had little effect on fluorite flotation using sodium oleate (NaOl) as the collector, suggesting the sufficient separation of fluorite from barite using the reagent scheme of GS/NaOl. However, the flotation of mixed minerals presented that the existing of fine barite particle significantly interfere with the fluorite flotation. Zeta potential measurements, turbidity tests, and light microscope observations revealed that the hetero-coagulation occurred between fluorite and barite slimes, causing the slime coating of barite onto the fluorite surface. GS not only acted as the depressant but also act as the flocculant to improve the apparent size of barite, while it still could not completely eliminate the detrimental effects of slime coating due to the entrainment of fluorite-barite aggregates. The additional methods to obtain the effective flotation separation of fluorite from barite slime were tested and discussed. • Roles of barite size on the fluorite flotation using the reagent scheme of GS/NaOl were studied. • The barite particle size significantly affected the fluorite flotation in mixed mineral flotation. • The hetero-coagulation between fluorite and barite slimes caused the adverse “slime coating”. • GS could act as depressant and flocculant to enhance the flotation separation efficiency. • Additional approaches were tested and discussed to further eliminate the slime coating effects.

Effect of particle number density on rheological properties and barite sag in oil-based drilling fluids

The effect of barite particle mass fraction and of particle size distribution on the settling and sag potential in oil-based drilling fluid samples is investigated for four fluids with densities of 1.43, 1.55, and 1.60 specific gravity (S.G). The fourth fluid sample, with density 1.60 S.G., had sieved barite particles of sizes less than 40 μ m . The settling potential in a liquid column under static condition has been characterized using light scattering measurements whereas sag potential in a sheared liquid column has been characterized under a dynamic condition using a rotating cylinder rheometer to produce rotational shear. Extensive rheological characterization of the drilling fluid samples is carried out where the Herschel-Bulkley fluid parameters were defined. We observed that the rate of particle settling under static condition was faster in the fluid sample of S.G = 1.43 having the least barite concentration. There was longer suspension of particles within the fluid sample of S.G = 1.60. Fluid sample with the sieved barite recorded weak destabilization of particles within the middle and bottom column of the sample after 7 days. The viscosity and viscoelastic-linear elasticity also increased with increasing barite concentration which contributed to lower dynamic sag for all shear rates. Time-dependent oscillatory shear measurements provide new insights on the structural character of drilling fluids to predict barite sag tendencies during the fluid design phase. • Barite sag in typical North sea oil-based drilling fluids is investigated. • Fluid viscosity and viscoelastic-linear elasticity increase with increasing barite concentration. • Yield stress values are strongly dependent on barite particle concentration. • The rate of particle migration is much faster in fluid sample with low barite concentration. • Time-dependent oscillatory shear analysis provide valuable information on the breakdown and growth of fluids' microstructures.

A Physicochemical Model of Gold Transformation in the Wastes of Processed Pyrite–Polymetallic Ores (Salair Ridge, Russia)

Abstract —Gold-bearing dumps of processed pyrite–polymetallic ores of the Ursk ore field (Novo-Urskoe and Beloklyuchevskoe deposits, Salair Ridge) have been studied. Physicochemical modeling of the gold behavior in wastes allowed us to describe quantitatively the gold precipitation process in different horizons of the dumps. In the upper part of the sulfide-rich section, sulfide minerals undergo intense oxidation accompanied by the dissolution of structural and surface-bound gold. Gold redeposition on the pyrite surface (sorption reduction barrier) as a result of electrochemical processes is accompanied by the formation of heavy-metal sulfates and barite. Under the sorption barrier, there is a loose leaching horizon with high humidity, where gold is present in pore solutions as thiosulfate, hydrosulfide, and hydroxo complexes; its content reaches 68 mg/L. In the middle part of the section, composed of compact siliceous sandstones (hardpan), high-grade (up to 973‰) gold forms through the disintegration of thiosulfate complexes, but its content decreases to 10-6 mg/L (lithologic reduction barrier). No visible gold was found in the lower part of the section (soil bed), but its high contents (up to 0.35–0.42 g/L) might be due to the sorption by organic high-molecular compounds, such as humic acids. The morphology and chemical composition of native gold from the gold-containing dumps of processed pyrite–polymetallic ores have been first studied. It is shown that the gold surface has traces of supergene transformations, e.g., gold nano- and microparticles as sponge overgrowth on the gold or barite particle surface or as newly formed gold phases in Fe, Mn, and Al hydroxide films.

Evaluating the effect of using micronised 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]

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]

Effect of Particle Size Distribution on Fluid Rheology of High Density Drilling Fluid

The control and maintenance of rheological properties is the key technical problem that needs to be solved for high density drilling fluid. The influence of particle size distribution on the rheology of high density drilling fluid is analyzed. In order to identify the best particle size distribution of barite and iron ore, the influence of distribution modulus on the rheology of high density drilling fluid weighted by barite and iron ore is investigated based on the Aflred distribution equation. The experimental results show that weighting materials particle distribution has great effect on rheological properties of high density drilling fluid. When the barite particle distribution modulus n=0.4 and iron ore powder particle distribution modulus n=0.6, the rheology of high density drilling fluid is best, while the low settlement density difference and low HTHP filtrate loss is maintained.

Application of arsenic in barite as a redox indicator for suboxic/anoxic redox condition

Redox condition is an important factor that controls the behavior of various elements in an aquatic environment. Incorporation of redox-sensitive trace elements in minerals describes redox conditions in water and provides information about past environmental changes, unless it is dissolved or recrystallized during sediment burial. In the present study, we explore the application of arsenate/arsenite ratios (As(V)/As(III)) in barite as a new geochemical proxy for paleo-environmental reconstruction. Laboratory experiments showed that both As(III) and As(V) could be incorporated into barite as As(III)- and As(V)-coprecipitated barite, respectively, which could more or less retain the information of the As(V)/As(III) ratio in coexistent water, if under equilibrium in terms of the redox reactions. Furthermore, the As(V)/As(III) ratios in natural barite collected in (i) Tamagawa Hot Spring and (ii) Okinawa hydrothermal vent were determined by micro-X-ray fluorescence and micro-X-ray absorption fine structure analysis to (a) evaluate the reliability of the As(V)/As(III) ratio in barite as a redox indicator in natural system and (b) estimate the depositional redox condition in water whether barite precipitated below or above the redox boundary of As(V)/As(III), or the suboxic/anoxic boundary. Our previous study showed that barite–selenium oxyanion system could also be used as a proxy for the oxic-suboxic boundary because the selenate/selenite [Se(VI)/Se(IV)] ratio in barite is primarily correlated with the ratio in water. Given that the redox boundary of the Se(VI)/Se(IV) ratio has higher redox potential than the As(V)/As(III) boundary, the combination of these two systems can extend the redox condition, which can be specified by the analysis of one single barite grain to a wide region. Thus, one barite particle can provide information on the As(V)/As(III) and Se(VI)/Se(IV) ratios in water, and whether barite precipitated under oxic, suboxic, or anoxic redox environments.

Impact of Antiscalants on the Fate of Barite in the Unconventional Gas Wells

Abstract Formation of barite (BaSO4) scale is a potential problem for unconventional (shale) gas extraction, as the excessive scale can reduce well productivity by plugging the proppant pack. This study was designed to evaluate the impact of antiscalants on the formation and transport of barite particles through proppant sand under well-controlled laboratory conditions using batch and column experiments. Extensive attachment of BaSO4 particles to proppant sand was observed at typical background salinity and in the absence of antiscalants due to relatively large barite particle size and screened electrostatic interaction. Presence of polymeric antiscalants can enhance the mobility of BaSO4 particles by decreasing their size and providing electrosteric repulsion. Ethylene glycol that may be added to hydraulic fracturing fluid to prevent scale deposition can reduce the size of BaSO4 precipitates but has no impact on the deposition of BaSO4 particles during transport through proppant sand. Polymaleic acid and...

The Effects of Particle Size and Viscosity on Settling Behaviour and Rheological Performance of Isopropyl Laurate Drilling Fluid

Density and viscosity are two major rheological properties that determine the performance of an isopropyl laurate (IPL) ester based drilling fluid. In this study, the effect of barite particle size on the IPL drilling fluid system settling behaviour was investigated using five particle sizes namely-32, 32-45, 45-75, +75μm and the unsieved barite. Stokes’ law of separation theory was employed in the analysis. It was found that smaller barite particle sizes (<75μm) enhances the settling resistance. An ideal barite particle size of-32μm was chosen and used in the subsequent formulations to obtain optimum rheological properties by varying the amount of viscosifier used at 4.0, 10.0 and 20.0g marked as sample (a), (b) and (c). These samples were analysed for their rheology by using the conventional Fann viscometer calibrated using Bingham model. The results showed that sample (b) exhibited the most promising performance based on the plastic viscosity, yield point and gel strength rheological analyses. Moreover, IPL drilling fluid sample (b) showed improve particle suspension ability for more than 78 hours when compared to IPL drilling fluid system prepared using unsieved barite particles. The results suggested that palm oil based isopropyl laurate ester has the potential to be used as based fluid in the ester based drilling fluid system.

Application of Ultrafine Weighting Materials in High-Density Oil-Based Drilling Fluid Technology

High-density oil-based drilling fluid already was considered as one of the most effective technologies during the HTHP Ultra-deep well drilling process. The weighting materials sag such as barite sag, however, always occurred because of the density contrast between the base oil and the weighting material, and hence sag can result in excessive torque, lost circulation and many other problems. This study applied three kinds of ultra-fine powder (particle size≤4μm), which are new weighting materials, to replace the common API barite (particle size10~70μm). The different kinds of high-density oil-based drilling fluids, which weighted with micronized barite, micronized ilmenite, manganese tetraoxide and API barite, were prepared and evaluated separately in lab. The performance data showed that compared with conventional weighting materials, the application of ultrafine powder technology could greatly optimize the rheology of high-density oil-based drilling fluids (ρ ≥ 2.3 g/cm3), reduce the amount of emulsifiers about 50% and dramatically enhance the dynamic suspension-stability of the system, Furthermore, OBM drilling fluids weighted with ultrafine weighting materials almost presented lower viscosity, shear force and sedimentation rate, which will meet more severe requirements of ultra-deep complex well drilling.

Preparation and Characterization of Barite/TiO2Composite Particles

To make full use of barite mineral and obtain a kind of composite particles material which has the property of both barite and TiO2, the composite particles material with TiO2coated on the surface of barite particle was prepared by the method of TiOSO4solution chemical hydrolysis and precipitation to form hydrolysis composite, removing the impurities of hydrolysis composite, drying, and calcination in this study. The results were evaluated by the covering power of composites. Composite structure and properties were characterized by means of XRD, SEM, FTIR, and XPS. The results showed that the surface of barite had been coated with rutile TiO2uniformly and compactly and the hiding power value and oil absorption value of the composite powder were 18.50 g/m2and 15.5 g/100 g, respectively, which had similar pigment performances to TiO2. The results also showed that it was mainly the strong chemical bond between barite and TiO2that combined them firmly in barite/TiO2composite particle (B/TCP).

Barite Segregation In Inclined Boreholes

Abstract Settling and sagging of barite in inclined boreholes may lead to safety and operational problems. To study the effect of rheology on settling, a laboratory tool was designed, consisting of two connected tubes, one inclined and one vertical. The hydrostatic pressure was measured at the bottom of each pipe. Stable and unstable muds can clearly be differentiated through their pressure behaviour. Several muds were studied at simulated static and dynamic conditions. The results show that sagging is most severe during laminar flow and also indicate that the rheological parameters may be used for predicting stability problems. Introduction In weighted drilling mud barite tends to segregate slowly. In directional drilling operations the settling process is accelerated. Barite settles in the lower side of the borehole and starts sliding when the borehole has an inclination above 30 °. This phenomenon is known as barite sagging. Sagging can lead to drilling and completion problems; a density variation or non-linear hydrostatic pressure gradients which can lead to pressure control problems, while thick and tight barite beds can lead to high torque and drag, stuck pipes and plugged boreholes, and even lost circulation. The sag problem is related to the so called Boycott effect(1), first described in 1920. Hanson et al.(2) have investigated the phenomenon and found that most of the sagging occurs while the mud is circulating. The same conclusion was reached by Bern et al.,(3) the sagging tendency is highest at low annular velocities. Zamora and Jefferson(4) presented a method for tracking drilling fluid density variations, which helps to detect, but not to predict drilling mud instability. Jamison and Clements(5) developed a test method to characterise settling and sag tendencies in static drilling fluids, however their equipment was not able to distinguish between settling and sliding. They also found that their data, based upon standard API rheological parameters like PV and YP, were unsuitable for prediction of sagging behaviour. It is apparent from previous works that the most difficult part of the problem is the prediction of drilling mud instabilities for both static and flowing drilling fluids. To date there are no API test procedures for sag testing. A new simple laboratory tool was therefore designed for the purpose to study and develop a method to predict sagging. Drilling Mud Separation Settling of Particles In vertical wells the settling of weighting material is generally not a problem due to the long settling distance. In horizontal wells the distance to the lower side of the wall is only about 0.2 m, which leads to rapid generation of solids beds. The settling velocity of a single spherical particle, vs,l, in a fluid is expressed by Stoke's law(6): Equation 1 (available in full paper) A barite particle (ρp = 4,200 kg/m3) with a diameter (dp) of 20 µm in a fluid of density (ρfluid) 1,500 kg/m3 and a viscosity (µ??of 40 cP will settle at a rate of 53 mm/h.

A New Device for Field Recovery of Barite From Drilling Mud: I. Theory and Laboratory Results

Abstract The inadequate use of centrifugation to economically recover solids from weighted drilling fluids reflects the need for better equipment and techniques for this purpose. Laboratory studies in the development of an improved separator are described in which an operating equation is derived and tested. Results show that the concentric cylinder geometry employed effectively separates barite from a suspension and that the operating equation provides a good approximation for scale-up. Introduction Our current drilling technology frequently requires a high-density drilling fluid obtained by addition of barite. In the course of drilling, formation solids which are too fine to be removed either by screening or settling become suspended in the drilling fluid and gradually the volume of solids in the mud increases. The volume fraction of solids must be limited (if a satisfactory set of rheological parameters are to be maintained). A centrifugal separator provides an economical way of accomplishing this. The barite recovery process can be considered as a separation of two solids. One, the light solids, composed of formation and added solids, has a specific gravity of 2.6 to 2.7; the other, barite, has a specific gravity of 4.2 to 4.3. This density difference, plus the fact that the average light-solids particle size is much smaller than the average barite particle size, permits separation by a centrifuge. In drilling fluids some of the coarse particles of the light-solids-range will settle faster than fine particles of the barite-particle range. As a result a complete separation of the two species is not possible. Since the object of the process is not merely recovering the maximum amount of barite but includes as well removing the maximum amount of light solids, an optimum barite recovery efficiency exists. From a practical standpoint this optimum cannot be determined in the field for each drilling fluid system, and in practice the separation is less than optimum, with some sacrifice of barite. Drilling technology has included centrifugal separators for barite recovery for more than a decade. Results have been reported by a number of investigators indicating that the process is practical and economical. The decision to use a centrifuge is based on economics in which direct cost savings and the indirect benefits in rig time derived from improvement of the drilling fluid are important factors. One would expect that centrifugal separation of barite from drilling fluids would significantly affect barite consumption; however, this is not the case. The Minerals Yearbook shows an annual domestic barite consumption in the drilling industry of nearly I million tons. By rough estimate there are perhaps 80 separators presently in field use. Assuming half of these in use at any one time, operating an, average of four hours per day, at recovery rates averaging 3,000 lb of barite per hour, total annual recovery is about 90,000 tons. This is less than 10 per cent of the total barite used. I conservatively estimate that barite consumption in drilling operations can be reduced by 30 per cent through greater utilization of centrifugal separators. To encourage more wide- spread acceptance of centrifugal separators in the drilling industry, improved equipment and techniques would be very desirable. The present paper, covering theory and results obtained from a laboratory model, is the first in a series on the development of an improved mud separator for field use. THE CONCENTRIC CYLINDER GEOMETRY AS A SEPARATING DEVICE Consider the geometry shown in Fig. 1, consisting of two concentric cylinders separated by an annular space. These are arranged so that the outer cylinder is fixed and the inner one can be rotated about its axis on shafts sealed against the ends of the outer cylinder. SPEJ P. 6ˆ