On the physical and chemical stability of shales

Oort, Eric van

doi:10.1016/s0920-4105(03)00034-2

Cited by 355 publications

(120 citation statements)

References 23 publications

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“…Shale formations consist of consolidated clay minerals and contain native fractures and nano-pores. This results in their ultra-low permeability (van Oort 2003;Zhang et al 2013;Zhong et al 2011) and serious clay swelling when encountering water, a main factor causing hole collapse, wellbore weakening, and stuck pipes in drilling (Zhong et al 2015). The composition of clay minerals is a major factor contributing to swelling capability as some clay minerals are non-swelling.…”

Section: Introductionmentioning

confidence: 99%

The assembly of a composite based on nano-sheet graphene oxide and montmorillonite

Weijia

et al. 2018

Pet. Sci.

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Graphene oxide (GO) nano-sheets were synthesized using a modified Hummers' method from graphite powder. The Raman spectrum of GO displayed a D-band at 1359 cm -1 and a G-band at 1594 cm -1 . The I D /I G value of GO was calculated to be 0.97, suggesting the formation of new sp 2 clusters upon reduction. A method was designed to investigate the assembly of the GO/montmorillonite (MMT) composite. After the addition of GO, the typical peaks of montmorillonite in FT-IR spectra shifted, indicating the assembly between GO and MMT. The D-band and G-band reduced sharply in the GO/MMT composite. More importantly, the D-band (1344 cm -1 ) and G-band (1574 cm -1 ) shifted significantly and the I D / I G value of the GO/MMT composite was calculated to be 1.13, showing a change in the GO structure. In the addition of 0.04 wt% GO to MMT, the value of interlayer space (d) was up to 13.0 Å measured by XRD due to the insertion of GO into MMT. The evident increases in contents of carbon atoms (26.59%) and nitrogen atoms (3.44%) indicate that GO was successfully combined with MMT. The nano-pores and clay sheets were not observed in the SEM image of GO/clay, but obvious wrinkles, while flexible sheets were observed in the typical scanning electron microscopy images of GO. This further proves that GO was combining with clay. The TEM image shows that the GO nano-sheets were tiled on the surface of MMT sheets. This observation suggests that a stable assembly structure was formed between GO sheets and MMT sheets. The change in particle size of MMT with the addition of GO shows that interaction occurred between GO sheets and MMT sheets, which was further confirmed by the results of zeta potential. Adsorption and insertion were the main mechanisms to assemble GO and MMT.

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Section: Introductionmentioning

confidence: 99%

The assembly of a composite based on nano-sheet graphene oxide and montmorillonite

Weijia

et al. 2018

Pet. Sci.

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“…During the past decades, extensive work has been carried out to evaluate and find solutions to mitigate and control the interaction between shale formations and drilling fluid [6], and many of the chemical inhibitor additives including potassium, sodium and calcium salts, PHPA, polyglycols, silicates, amine compounds and formates have been developed to improve the inhibition comparable to the oilbased drilling fluids [7,8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cycloaliphatic Amine on the Shale Inhibitive Properties of Water-Based Drilling Fluid

Zhong¹,

Sun²,

Huang³

et al. 2015

TOEFJ

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Abstract:In order to improve the inhibitive properties and high temperature resistance of shale inhibitor, cycloaliphatic amines were introduced as shale hydration inhibitors in water-based drilling fluids. Bulk hardness test, shale cuttings dispersion test, bentonite inhibition test and water adsorption test were carried out to characterize the inhibitive properties of the novel amines. Surface tension measurement, zeta potential measurement, XRD, contact angle test, SEM and TGA were performed to investigate the interaction between the cycloaliphatic amines and clay particles. The results indicated that cycloaliphatic amines exhibited superior inhibitive properties to the state of the art inhibitors. Moreover, the amines were high temperature resistant. The hydrophobic amine could intercalate into the clay gallery with monolayer orientation. The protonated ammonium ions neutralized the negatively charged surface. After adsorption, the hydrophobic segment covered the clay surface and provided a shell preventing the ingress of water.

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“…Based on the second approach, a variety of water-based drilling fluids and non-aqueous fluids have been applied; meanwhile, many types of wellbore stabilizers have been developed. These wellbore stabilizers have been classified into several groups, including inorganic salts, formate, polymers with special shale affinity, asphalts, sugars and sugar derivatives, glycerol, polyalcohol, and silicates (Van Oort 2003;Guo et al 2006;Khodja et al 2010;Jiang et al 2011;Zhong et al 2011). Among of them, asphalts as one type of cheap and effective stabilizer can improve wellbore stabilization mainly through plugging or sealing, and they have been divided into four varieties according to modification methods: natural asphalt (no modification, mined from deposit), oxidized asphalt (oxidation by air blown to heighten softening point), sulfonated bitumen (changed into asphalt sulfonate partly to enhance water solubility), and emulsified asphalt (oil in water emulsion to improve dispersion in the drilling fluid and adsorption on the rock surface) (Sharma and Wunderlich 1987;Wang et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Development and evaluation of an electropositive wellbore stabilizer with flexible adaptability for drilling strongly hydratable shales

et al. 2015

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In order to overcome serious instability problems in hydratable shale formations, a novel electropositive wellbore stabilizer (EPWS) was prepared by a new approach. It has good colloidal stability, particle size distribution, compatibility, sealing property, and flexible adaptability. A variety of methods including measurements of particle size, Zeta potential, colloidal stability, contact angle, shale stability index, shale dispersion, shale swelling, and plugging experiments were adopted to characterize the EPWS and evaluate its anti-sloughing capacity and flexible adaptability. Results show that the EPWS has advantages over the conventional wellbore stabilizer (ZX-3) in particle size distribution, colloidal stability, inhibition, compatibility, and flexible adaptability. The EPWS with an average particle size of 507 nm and an average Zeta potential of 54 mV could be stable for 147 days and be compatible with salt tolerant or positive charged additives, and it also exhibited preferable anti-sloughing performance to hydratable shales at 77, 100, and 120°C, and better compatibility with sodium bentonite than ZX-3 and KCl. The EPWS can plug micro-fractures and pores by forming a tight external mud cake and an internal sealing belt to retard pressure transmission and prevent filtrate invasion, enhancing hydrophobicity of shale surfaces by adsorption to inhibit hydration. The EPWS with flexible adaptability to temperature for inhibition and sealing capacity is available for long open-hole sections during drilling.

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On the physical and chemical stability of shales

Cited by 355 publications

References 23 publications

The assembly of a composite based on nano-sheet graphene oxide and montmorillonite

The assembly of a composite based on nano-sheet graphene oxide and montmorillonite

Effect of Cycloaliphatic Amine on the Shale Inhibitive Properties of Water-Based Drilling Fluid

Development and evaluation of an electropositive wellbore stabilizer with flexible adaptability for drilling strongly hydratable shales

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