Anhydrite (Calcium Sulfate) Mineral as a Novel Weighting Material in Drilling Fluids

Murtaza, Mobeen; Tariq, Zeeshan; Mahmoud, Mohamed; Kamal, Muhammad Shahzad; Shehri, Dhafer Al

doi:10.1115/1.4047762

Cited by 14 publications

(7 citation statements)

References 34 publications

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Section: Introductionmentioning

confidence: 99%

“…18 A recent study has shown that anhydrite (calcium sulfate) can be used as a new type of drilling fluid weighting material, thus placing great demands on the resistance of other treatments in WBDFs to Ca 2+ . 19 To improve the filtration performance of bentonite suspensions, various polymer-based fluid loss agents, such as xanthan gum, 20,21 starch, 22 cellulose, 8 and various synthetic polymers, 23−25 are usually added to WBDFs. Table 1 summarizes the temperature and salt resistance of polymeric fluid loss control agents used in high-temperature and highsalinity formations.…”

Section: Introductionmentioning

confidence: 99%

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An Inverse Emulsion Polymer as a Highly Effective Salt- and Calcium-Resistant Fluid Loss Reducer in Water-Based Drilling Fluids

Shan

Jiang

et al. 2022

ACS Omega

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To control the fluid loss of water-based drilling fluids (WBDFs) in salt-gypsum formations, a nano-SiO 2 graft copolymer was prepared by inverse emulsion polymerization. The polymer (EAANS) was prepared with acrylamide, 2-acrylamido-2-methyl-1-propane sulfonic acid, N-vinylpyrrolidone, and KH570-modified nano-silica (M-SiO 2 ) as raw materials. The molecular structure and morphology of EAANS were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis, transmission electron microscopy (TEM), and other methods. In the temperature range of 150 °C, 2 wt % EAANS can reduce the API filtration volume of the base slurry to within 20 mL and the HP-HT filtration volume at 150 °C to 21.8 mL. More importantly, 2 wt % EAANS can maintain the API filtration volume less than 10 mL even when the concentration of NaCl or CaCl 2 was as high as 36 or 30 wt %, and as the salt/calcium content increased, the amount of filtration continued to decrease. The results of TEM, X-ray diffraction, particle size distribution, and scanning electron microscopy showed that the fluid loss control mechanism of EAANS was that EAANS can form a crosslinked network structure in the solution and adsorb on the clay surface, so as to reduce the particle size of clay particles, increase the proportion of fine particles in drilling fluids, and finally form a dense filter cake to reduce the filtration volume. Because of the excellent filtration performance of EAANS at high Na + /Ca 2+ concentration, EAANS can become a promising WBDF fluid loss reducer in salt-gypsum formations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Inverse Emulsion Polymer as a Highly Effective Salt- and Calcium-Resistant Fluid Loss Reducer in Water-Based Drilling Fluids

Shan

Jiang

et al. 2022

ACS Omega

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“…It could not be used as a weighting material because of the poor solubility of its filter cake. For the first time, Murtaza et al 34 reported CaSO 4 as a weighting agent in WBDFs. They reported numerous advantages of CaSO 4, such as higher solubility in the drilling fluid and improved rheology over CaCO 3 .…”

Section: Introductionmentioning

confidence: 99%

Application of Anhydrous Calcium Sulfate as a Weighting Agent in Oil-Based Drilling Fluids

et al. 2021

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The hydrostatic pressure exerted during the drilling operation is controlled by adding a weighting agent into drilling fluids. Various weighting materials such as barite, calcium carbonate, hematite, and ilmenite are used to increase the density of drilling fluids. Some weighting additives can cause serious drilling problems, including particle settling, formation damage, erosion, and insoluble filters. In this study, anhydrite (calcium sulfate) is used as a weighting additive in the oil-based drilling fluid (OBDF). Anhydrite is an abundantly available resource used in the preparation of desiccant, plaster of Paris, and Stucco. Anhydrite application in drilling fluids is discouraged because of its filter cake removal issue. This study investigated anhydrite (anhydrous CaSO 4 ) as a weighting agent and its filter cake removal procedure for OBDFs. The anhydrite performance as a weighting agent in OBDFs was evaluated by conducting several laboratory experiments such as density, rheology, fluid loss, and electrical stability and compared with that of commonly used weighting materials (barite, calcium carbonate, and hematite). The anhydrite was mixed in three different concentrations (62, 124, and 175 ppb) in a base-drilling fluid. The results showed that calcium sulfate enhanced rheological parameters such as plastic viscosity, yield point, apparent viscosity, and gel strength. CaSO 4 reduced the fluid loss and provided better control over the fluid loss than other tested weighting materials tested at the same concentration of 124 ppb. Similarly, the emulsion stability was decreased with the increase in the amount of calcium sulfate in the OBDF. The calcium sulfate filter cake can be removed easily from the wellbore with an efficiency of 83 to 91% in single-stage and multistage removal processes, respectively using the newly developed formulation consisting of 20 wt % potassium salt of glutamic acid-N,N-diacetic acid (K 4 GLDA) as a chelating agent, 6 wt % potassium carbonate, and 10% ethylene glycol monobutyl ether. The introduction of anhydrite as a weighting agent can be more beneficial for both academia and industry.

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“…Solids sag is experienced with weighted drilling fluids, where weighting agents are present in the drilling fluid formulation to increase the mud weight and suppress the high formation pressure. 20 − 23 Many parameters contribute to the sagging phenomenon, such as drilling fluid properties, weighting agents, particle size, downhole conditions, time, pipe rotation, well inclination, and well geometry. 24 − 26 The sagging phenomenon mechanism is that the solid particles separate from the liquid phase and start to accumulate downhole, causing the density of the drilling fluid column to vary with the depth ( Figure 1 ).…”

Section: Introductionmentioning

confidence: 99%

“…Solids sag, or barite sag, is the separation of solid particles from the liquid phase. Solids sag is experienced with weighted drilling fluids, where weighting agents are present in the drilling fluid formulation to increase the mud weight and suppress the high formation pressure. − Many parameters contribute to the sagging phenomenon, such as drilling fluid properties, weighting agents, particle size, downhole conditions, time, pipe rotation, well inclination, and well geometry. − The sagging phenomenon mechanism is that the solid particles separate from the liquid phase and start to accumulate downhole, causing the density of the drilling fluid column to vary with the depth (Figure ). Consequently, the mud weight becomes less than the formation pressure in the upper parts of the drilled section, which may cause a severe well control issue. , The solid particles, accumulated in the lower part of the well, increase the mud weight and equivalent circulating density (ECD).…”

Section: Introductionmentioning

confidence: 99%

Impact of Perlite on the Properties and Stability of Water-Based Mud in Elevated-Temperature Applications

et al. 2020

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Barite settling is one of the common drilling fluid issues encountered while drilling deep wells. In this study, the effect of perlite on the properties and stability of water-based drilling fluid was investigated. Perlite is an inexpensive additive used in different industrial applications such as bricks, concrete, thermal insulators, sludge absorbents, fillers, tiles, ruminants, and poultry. Perlite additive was also introduced to the oil industry in drilling applications as an effective fluid loss control agent to reduce the drilling fluid invasion into the formations. Perlite was added to the drilling fluid in various concentrations, ranging between 0 and 3.0 lb/bbl. The sag test was performed to assess the drilling fluid’s stability under dynamic and static conditions at a temperature of 120/250 °F. Then, the impact of perlite on the properties of drilling fluid was assessed by measuring the density and pH at room temperature. While the rheological, viscoelastic, and filtration properties were evaluated at 250 °F. This study showed that an increase in perlite concentration, from 0 to 3 lb/bbl, slightly reduced the pH of the drilling mud; however, all of the values were within the acceptable pH range (9–11). In contrast, this concentration of perlite had an immeasurable impact on drilling fluid density. Perlite enhanced the drilling fluid’s homogeneity and stability by reducing the dynamic and static sag factors, and 3.0 lb/bbl perlite was adequate to eliminate barite sag at a temperature up to 250 °F. Perlite was found to be effective in improving the rheological and viscoelastic properties. A significant enhancement of filtration properties was observed by the reduction in filtrate volume and filter cake thickness by 64 and 31%, respectively.

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Anhydrite (Calcium Sulfate) Mineral as a Novel Weighting Material in Drilling Fluids

Cited by 14 publications

References 34 publications

An Inverse Emulsion Polymer as a Highly Effective Salt- and Calcium-Resistant Fluid Loss Reducer in Water-Based Drilling Fluids

An Inverse Emulsion Polymer as a Highly Effective Salt- and Calcium-Resistant Fluid Loss Reducer in Water-Based Drilling Fluids

Application of Anhydrous Calcium Sulfate as a Weighting Agent in Oil-Based Drilling Fluids

Impact of Perlite on the Properties and Stability of Water-Based Mud in Elevated-Temperature Applications

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