Dynamic cross-linking mechanism of acid gel fracturing fluid

Zhao, Mingwei; Li, Yang; Xu, Zhongliang; Wang, Kai; Gao, Mingwei; Lv, Wenjiao; Dai, Caili

doi:10.1016/j.colsurfa.2020.125471

Cited by 21 publications

(12 citation statements)

References 20 publications

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“…As follows the 4‐parameter steady‐state crosslinking rheological kinetic equation 24,25 :

\begin{matrix} ([], η ((), t) goodbreak- η_{\max}) / ((), η_{c} goodbreak- η_{\max}) goodbreak= 1 / ([], 1 goodbreak+ {(italickt)}^{p}) \end{matrix}

η(t) is the viscosity corresponding to the moment t, η c is the initial viscosity of the fluid, η max is the viscosity when the crosslinking reaction reaches equilibrium; k is the structural rate constant of the crosslinking reaction; p is the time‐dependent parameter of the crosslinking reaction.…”

Section: Methodsmentioning

confidence: 99%

“…The high‐temperature steady‐state shear experiment showed that the fracturing fluid could still reach a viscosity of 50 mPa s under shearing at 170°C. Other than that, few researchers studied the crosslinking process of guar gum‐based fracturing fluid, 22–24 and in this study, oscillatory shear experiments were conducted to analyze the gelation of the fracturing fluid. Moreover, steady‐state shear and micro‐rheological experiments were performed to analyze the dynamic and static crosslinking process of the fracturing fluid, respectively, which could provide reference to the crosslinking process of the fracturing fluid in fracturing operations.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and performance evaluation of crosslinker for seawater‐based fracturing fluid

Miao

Hai

et al. 2022

J of Applied Polymer Sci

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Zirconium is one of the most commonly used crosslinkers for guar gum‐based fracturing fluid. Nevertheless, it is difficult for zirconium crosslinkers applied in fracturing to possess both high temperature resistance and adjustable crosslinking time. Meanwhile, few people did systematical research on the crosslinking process of fracturing fluid. In this study, an organic zirconium crosslinker with high temperature resistance and controllable crosslinking time was synthesized. The seawater‐based fracturing fluid gel prepared with the crosslinker could perform well under 170°C. Oscillatory shear experiments were conducted to analyze the rheology of the gelation process. Moreover, steady‐state shear and micro‐rheological tests were conducted to analyze the dynamic and static crosslinking process of the fracturing fluid, respectively. Meanwhile, rheo‐kinetic equation was used to fit the data and the effects that various factors had on the gelation process were illustrated thoroughly. This study not only prepared an organic zirconium crosslinker with good performances, but also explored the crosslinking process of fracturing fluid gel, which could improve its further application in oilfields.

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“…As follows the 4‐parameter steady‐state crosslinking rheological kinetic equation 24,25 :

\begin{matrix} ([], η ((), t) goodbreak- η_{\max}) / ((), η_{c} goodbreak- η_{\max}) goodbreak= 1 / ([], 1 goodbreak+ {(italickt)}^{p}) \end{matrix}

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis and performance evaluation of crosslinker for seawater‐based fracturing fluid

Miao

Hai

et al. 2022

J of Applied Polymer Sci

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“…Emulsified acid is widely used in repeated acid pressure or high sulfur gas well acid pressure, and the use of emulsified acid in matrix acidification is also significantly increased. − Gelled acid can reduce the filtration loss of acid solution, form a colloidal network structure, and reduce the diffusion of H + . Thickened acid can form wide cracks, small filtration loss, and low friction and show good performance of suspended solid particles in the process of acid pressing. − Autogenic acid is an acid product produced in situ by chemical dissociation or reaction of fluid injected into the formation. It has no acidity or weak acidity on the surface, but acid is produced gradually at the bottom of the hole temperature, and acid production is carried out gradually, which can effectively reduce the acid rock reaction rate, prolong the acid action distance, and reduce the corrosion effect on the underground pipe string. − …”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Autogenic Acid Fluid System of a High-Temperature Carbonate Reservoir by Acid Fracturing

Guo

Liu

et al. 2022

ACS Omega

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As an important part of the acid fracturing process of carbonate reservoir, the performance of acid fracturing working fluid directly affects the stimulation effect of oil wells. In this paper, formaldehyde (agent A) and ammonium chloride (agent B) were used as the matrix. Several aldehydes with different volume ratios were prepared. The acid ratio with the highest acid yield was selected by the sodium hydroxide titration experiment. The results show that when the volume ratio of agent A to agent B is 1:1.3, the acid production capacity is the strongest. The pH values at several time points in the process of acid reaction were measured by a pen pH meter. The relationship curve between acid production capacity and time was obtained. The acid production capacity increased with time. It tends to be stable after a certain time. The experiment of acid rock reaction kinetics shows that the reaction rate between acid and rock decreases with the extension of time. The reaction time can reach 6 h. The reaction rate of autogenic acid under different temperatures and concentrations ranges from 6.61 × 10 –7 to 9.49 × 10 –7 mol/(s·cm 2 ) within 6 h. Therefore, it indicates that the reaction time between autogenic acid and carbonate rock is long and the reaction rate is low. It is beneficial to improve the acid treatment effect of the carbonate reservoir. The conductivity experiments show that at different temperatures, with the increase of sealing pressure, the etching ability of autogenic acid decreases. The etching effect is better at 338 K. After etching, the permeability and conductivity of the rock slab of 5 MPa closure pressure are 227 D and 72.62 D·cm, respectively. To sum up, this autogenic acid is an effective working fluid in the acid fracturing process of the carbonate reservoir. It can obviously reduce the reaction rate of acid rock and has certain conductivity.

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“…Adding a small amount of thickener to the required thickening system can significantly increase the apparent viscosity of the system. At present, thickeners are widely used in oil exploitation [ 3 ], agriculture [ 4 ], food processing [ 5 ], daily chemical products [ 6 ], textile printing and dyeing [ 7 ], the pharmaceutical industry, and other fields [ 8 , 9 , 10 , 11 ]. With the development of industry, the variety of thickeners is gradually increasing, among which cellulose [ 12 ] and polyacrylic acid thickeners [ 8 ] are the most widely used.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Application of Tackifying Dispersant Poly (Vinyl Alcohol-Acrylic Acid-Triallyl Cyanate)

Chen

Huang

et al. 2022

Polymers

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At present, the thickener market is relatively advanced. Only by imparting thickeners with new properties can they meet the needs of the current market. In this work, a new modified tackifying dispersant poly (vinyl alcohol-acrylic acid-triallyl cyanate) (PVA-AA-t) was prepared via alcoholysis of a random copolymer composed of vinyl acetate (VAc), acrylic acid (AA), and triallyl cyanate (TAC) by a one-step high-temperature solution polymerization in methanol, which was a relatively simple method. The structure of the polymer was characterized by FTIR and TG. FTIR proved the successful synthesis of PVA-AA-t, while TG showed the thermal stability of PVA-AA-t at around 100 °C. The excellent thickening properties of the PVA-AA-t were observed using a nano particle size analyzer and a rotary viscometer. The nano particle size analyzer showed that the PVA-AA-t particles swelled in water to nearly nine times their initial size. The rotary viscometer showed that the viscosity of PVA-AA-t in water increased significantly, while PVA-AA-t was sensitive to electrolytes and pH, which changed the polymer molecular chain from stretched to curled, resulting in a decrease in viscosity. In addition, the dispersion properties of PVA-AA-t and a common thickener as graphene (Gr) dispersants were compared. The results indicate that PVA-AA-t has very good compatibility with Gr, and can effectively disperse Gr, because of the introduction of weak polar molecules (VAc) to the polymer molecules, changing their polarity, meaning that it is possible to use PVA-AA-t in the dispersion of Gr and other industrial applications (such as conductive textile materials, Gr batteries, etc.) derived from it.

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Dynamic cross-linking mechanism of acid gel fracturing fluid

Cited by 21 publications

References 20 publications

Synthesis and performance evaluation of crosslinker for seawater‐based fracturing fluid

Synthesis and performance evaluation of crosslinker for seawater‐based fracturing fluid

Experimental Study on the Autogenic Acid Fluid System of a High-Temperature Carbonate Reservoir by Acid Fracturing

Synthesis and Application of Tackifying Dispersant Poly (Vinyl Alcohol-Acrylic Acid-Triallyl Cyanate)

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