Properties and Applications of an Alternative Aminopolycarboxylic Acid for Acidizing of Sandstones and Carbonates

Reyes, Enrique A.; Smith, Alyssa L.; Beuterbaugh, Aaron

doi:10.2118/165142-ms

Cited by 27 publications

(10 citation statements)

References 29 publications

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“…APCAs have been used in the oil field to remove carbonate and sulfate scales (Shaughnessy and Kline 1983;Tyler et al 1985;Rhudy 1993;Fredd and Fogler 1998). HEDTA prevents precipitation of Fe þ3 species better than EDTA because it has a higher solubility in hydrochloric acid than EDTA.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability of Oilfield Aminopolycarboxylic Acids/Salts

Sokhanvarian

Nasr‐El‐Din

Wolf

2016

SPE Production &Amp; Operations

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Summary Chelating agents are used to remove various inorganic scales, including sulfates and carbonates. They are also used as standalone stimulation fluids and as iron-control agents during acidizing treatments. The main chelating agents used in the oil field include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), and glutamic acid diacetic acid (GLDA). (Note that the abbreviations for these chelating agents will be used throughout the rest of the paper.) One of the concerns with these chelants is their thermal stability at elevated temperatures. Chelant solutions (0.7 to 0.8 M) of HEDTA, GLDA, NTA, EDTA, and their mono-/disalts were prepared. The aqueous solutions of these chelants were heated at various temperatures (300 to 400°F) and times (2 to 12 hours). The concentration of chelant was measured with a titration method that uses FeCl3 solutions. The products of thermal decomposition of chelants were determined with mass spectrometry (MS) and gas-chromatography/MS techniques. Most chelants decomposed at temperatures greater than 350°F. At 400°F and after 12 hours of heating, diammonium salt of GLDA degraded more quickly than diammonium salt of EDTA chelant. Analyses of NH4H3GLDA with MS techniques after heating highlighted that the decomposition products included iminodiacetic acid, hydroxyacetic acid, and α-hydroxyglutaric acid. Studying the kinetics of aqueous solutions of NaH3GLDA, NaH2HEDTA, and (NH4)2H2EDTA showed that their thermal-degradation kinetics followed a pseudofirst-order reaction. The Arrhenius equation can be used to predict the activation energy that is necessary for the degradation mechanisms of chelants.

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Section: Introductionmentioning

confidence: 99%

Thermal Stability of Oilfield Aminopolycarboxylic Acids/Salts

Sokhanvarian

Nasr‐El‐Din

Wolf

2016

SPE Production &Amp; Operations

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“…While the most common and cost-effective treatment fluid is a combination of HCl and HF acid (mud acid) containing a plethora of additives to mitigate acid-wellbore fluid-hydrocarbon incompatibilities, advances have been made in the last two decades in terms of fluid design. Specifically, fluid developments in HF acidizing have evolved around the substitution or elimination of HCl and, in other instances, acetic and/or formic acids, from the treatment fluid to eliminate the risks associated with such acids (Al-Anazi et al 2000;Al-Harbi et al 2012;Guichard III et al 1996;Jiang et al 2004;Mahmoud et al 2011;Reyes et al 2013b;Shuchart 1997;Shuchart and Gdanski 1996). Among the most effective substitutes are aminopolycarboxylic acids (APCA) and phosphonic acids caused by their intrinsic chemical properties among these high temperatures stability, better solubility in low pH media, and, most importantly, strong complexation capacity (Ali et al 2008;Di Lullo and Rae 1996;Husen et al 2002).…”

Section: Introductionmentioning

confidence: 99%

“…One of the potential problems associated with the use of HF in situations where there is calcium, naturally present or artificially introduced, is the formation and precipitation of CaF 2 . The single approach to circumvent this problem is to avoid the use of HF altogether, or minimize the concentration of HF to 1% w/v (Frenier et al 2004;Mahmoud et al 2014;Reyes et al 2013b). Otherwise, extensive preflush stages of acid and NH 4 Cl are necessary (Jiang et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In some instances, options are viable and good results can be obtained, provided the damage or mineral obstruction is predominantly CaCO 3 (Ali et al 2008;Frenier et al 2004). Recently, the introduction of APCA agents that are highly soluble in pH less than two have been introduced, among them GLDA Mahmoud et al 2011) and another new chelant (Reyes et al 2013a;Reyes et al 2013b). These chelating agents facilitate the preparation of fluids containing HF in concentrations at or above 1% HF, something not easily achievable with ethylenediamine tetraacetic acid (EDTA) or hydroxyethylenediamine triacetic acid (HEDTA) containing fluids.…”

Section: Introductionmentioning

confidence: 99%

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GLDA/HF Facilitates High Temperature Acidizing and Coiled Tubing Corrosion Inhibition

et al. 2015

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An existing limitation of chelant-based fluids available for sandstone acidizing with hydrofluoric acid (HF) is the presence of sodium in the concentrate of the aminopolycarboxylate fluid, which is common in all chelating agents soluble below pH 3.5. The presence of sodium complicates stabilization of the fluid during acidizing processes because of the myriad of chemical reactions that can impact the outcome of a treatment. The use of chelating agents has expanded the temperature range as well as the type of clay minerals that can be exposed to an HF fluid; however, limitations still exist. Core flow testing at 360°F and corrosion testing from 265 to 360°F were conducted. Flow tests were performed using outcrops of two types of sandstones and inductively coupled plasma (ICP) analysis was conducted to elucidate the ionic composition of the spent fluid. Results reported stem from core flow testing with glutamic acid diacetic acid (GLDA) containing HF at very high temperatures (360°F). To encompass a broad range of mineral composition, two types of sandstone cores were employed-heterogeneous (Bandera, 65% quartz) and clean (Leopard, 95% quartz). Corrosion inhibition of the GLDA/HF fluid for use with coiled tubing (CT) was achieved up to 320°F, employing varying classes of inhibitors. The GLDA/HF fluid exhibited lessened corrosion tendencies and could be inhibited for at least 6 hours at 360°F for drillpipe (mass loss rates of 0.025 to 0.05 in./ft 2 were obtained).The presence of sodium in GLDA/HF could be managed, leading to effective permeability improvement of the Bandera core, while the Leopard core underwent a decrease in overall permeability; this latter observation was attributed to the formation of metal fluorides. Neither the presence of CaCO 3 in the Bandera substrate or the use of KCl brine substituting for the usual NH 4 Cl led to permeability impairment. The overall results indicated that 1% HF and 0.6 M GLDA with an auxiliary agent could circumvent the expected problems associated with HF acidizing and modification, volume minimization, or elimination of preflushes. The use of the GLDA chelant facilitates, when using CT to deliver fluid to hot zones (which can be susceptible to formation damage if aggressive fluids based on HCl or formic acid are used, or if acetic acid is employed), could be jeopardized because of the difficulties inhibiting the corrosive effects of HF, HCl, formic, or acetic blends.

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“…Mahmoud et al used GLDA to stimulate carbonate (LePage et al 2011;Mahmoud et al 2011aMahmoud et al , 2011b and sandstone formations (Mahmoud et al 2015) to remove carbonates and oxides minerals. Reyes et al (2013) examined a new chelant. Chelants are less corrosive than organic acids (Nasr-El-Din et al 2012) and they do not cause asphaltene precipitation.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Methods to Improve Matrix Stimulation of Horizontal Carbonate Wellbores

Nasr‐El‐Din

Shedd²,

Germack³

et al. 2015

Day 2 Tue, November 10, 2015

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Acid stimulation of horizontal wellbores in high temperature and/or low permeability formations is complicated due to the need to balance acid reaction rates with the rate of formation penetration. At high bottom hole temperatures, uncontrolled acid spending rates result in inefficient or even damaging treatments. It is advantageous to add materials which slow the reaction of HCl or use alternative acids which are useful as alternative stimulation fluids, such as organic acids and chelants due to their inherently lower reaction rates. The slower reaction rate with carbonate minerals allows for optimal wormhole growth at the limited rates available in long horizontals. This study investigates the complementary use of acid or chelant systems together with a microemulsion delivery system to achieve the desired performance. These delivery systems can significantly increase the efficiency of HCl and chelant stimulation treatments of low-permeability carbonates by optimizing diffusivity and minimizing pressure to cleanup.Horizontal core flow experiments were conducted by injecting solutions of 15 wt% HCl and 10 -20 wt% alternative acids through low permeability (Ͻ 10 md) limestone cores. High permeability cores were also investigated by injecting 15 wt% HCl through high permeability (150 -200 md) Indiana limestone cores. These experiments were conducted with and without the addition of a microemulsion additive and at core injection rates from 0.2 -20 cm 3 /min corresponding to 0.25 to 5 BPM per 100 ft of a horizontal wellbore.Significant performance advantages were found with the addition of the microemulsion delivery system. The treatment volume required for wormholes to propagate the length of the test core was reduced at all flow rates at or above the optimum rate. Core penetration was more efficient when using the microemulsion, without an increase in pumping pressure. Initiation and extension of wormholes was improved, as compared to the experiments without the microemulsion, in which more conical wormholes tended to form at the inlet face. The reduction in treatment volume necessary to reach breakthrough with the microemulsion present also suggested a more efficient treatment.The complementary use of a microemulsion delivery system with acids and chelants has been shown to enhance acid stimulation treatment potential in long horizontal wellbores with high temperature or low permeability formations. This system can be used to optimize wormhole penetration while maintaining an optimum injection rate across long horizontal intervals where the maximum achievable injection rate is relatively low.

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Properties and Applications of an Alternative Aminopolycarboxylic Acid for Acidizing of Sandstones and Carbonates

Cited by 27 publications

References 29 publications

Thermal Stability of Oilfield Aminopolycarboxylic Acids/Salts

Thermal Stability of Oilfield Aminopolycarboxylic Acids/Salts

GLDA/HF Facilitates High Temperature Acidizing and Coiled Tubing Corrosion Inhibition

Evaluation of Methods to Improve Matrix Stimulation of Horizontal Carbonate Wellbores

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