Acidizing Gas Wells in the Merluza Field Using an Acetic/Formic Acid Mixture and Foam Pigs

Motta, E. Ponce Da; Quiroga, Maza; Aragao, Atila Fernando Lima; Pereira, Alexandre Zacarias Ignácio

doi:10.2118/39424-ms

Cited by 28 publications

(13 citation statements)

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“…Organic acids have been extensively used in the acid stimulation of hydrocarbon reservoirs (Harris 1961;Scheuerman 1988;Wehunt et al 1993;Fredd and Fogler 1998;Shuchart and Gdanski 1996;Coulter and Jennings 1997;Nasr-El-Din et al 1997;da Motta et al 1998;Huang et al 2000a, 200b;Wang et al 2000;Nasr-El-Din et al 2001;Frenier 1989;Hashem et al 1999;van Domelen and Jennings 1995;Smith et al 1970;Chatelain et al 1976). The use of a combination of organic and inorganic acids dates back to 1978 (Dill and Keeney 1978).…”

Section: Introductionmentioning

confidence: 99%

“…These treatments used a blend of 13% acetic/9% formic acid. Acetic/formic-acid blends were later used in the Merluza field of Brazil (da Motta et al 1998) and the Urdaneta west field near Lake Maracaibo, Venezuela (Buijse et al 2004). Most recently, stimulation programs in Lake Maracaibo have evolved to use a 11% formic/7% HCl blend (Burgos et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

Welton

Domelen

2008

SPE Production &Amp; Operations

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This paper discusses the development of a unique in-situ crosslinkable acid system that uses a blend of hydrochloric acid (Hcl)/ formic acid as the base acid and a synthetic polymer gelling agent. The ability to in-situ crosslink an organic acid blend is novel. In addition, an unexpected result of the fluid development was the discovery of its unique rheological properties.Historically, both gelled and in-situ-crosslinked acids have been used for fluid-loss control during fracture acidizing and for diversion in matrix treatments in carbonate formations. Various synthetic polymers are used to gel the acid. Past research indicates that ∼20 cp base-gel viscosity is required as the first step in fluidloss control. In-situ crosslinking allows very high viscosities to be generated as the acid spends. The crosslinked gel creates a permeability barrier and subsequent fluid stages are diverted to other sections of the zone. When the acid fully spends, the gel breaks, giving a low-viscosity fluid.HCl is the most common base acid used for carbonate stimulation. Combinations of HCl and organic acids have been used because of their high dissolving power and relatively low rates of corrosion at elevated temperatures. In extreme cases, combinations of organic acids are used. While HCl/formic-acid blends have been used in the past, the unique rheological properties of these blends have not been fully explored.The chemistry and rheology of gelled and in-situ crosslinked HCl/formic-acid blends equivalent to 28% HCl will be described and compared with traditional gelled acid and in-situ crosslinked acid.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

Welton

Domelen

2008

SPE Production &Amp; Operations

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“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] The use of a combination of organic and inorganic acids dates back to 1978. 30 More recently, Nasr-El-Din and coworkers studied the rates of reactivity by rotating disc method.…”

Section: Introductionmentioning

confidence: 99%

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

Welton

Domelen

2006

SPE International Symposium and Exhibition on Formation Damage Control

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper discusses the development of a unique in-situ crosslinkable acid system that uses a blend of HCl/formic acid as the base acid and a synthetic polymer gelling agent. The ability to in-situ crosslink an organic acid blend is novel. In addition, an unexpected result of the fluid development was the discovery of its unique rheological properties.Historically, both gelled and in-situ crosslinked acids have been used for fluid loss control during fracture acidizing and for diversion in matrix treatments in carbonate formations. Various synthetic polymers are used to gel the acid. Past research indicates that ~20 cp base gel viscosity is required as the first step in fluid loss control. In-situ crosslinking allows very high viscosities to be generated as the acid spends. The crosslinked gel creates a permeability barrier and subsequent fluid stages are diverted to other sections of the zone. When the acid fully spends, the gel breaks, giving a low viscosity fluid.HCl is the most common base acid used for carbonate stimulation. Combinations of HCl and organic acids have been used because of their high dissolving power and relatively low rates of corrosion at elevated temperatures. In extreme cases, combinations of organic acids are used. While HCl/formic acid blends have been utilized in the past, the unique rheological properties of these blends have not been fully explored.The chemistry and rheology of gelled and in-situ crosslinked HCl/formic acid blends equivalent to 28% HCl will be described and compared with traditional gelled acid and in-situ crosslinked acid.

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“…1 Formic acid was used with HCl for high-temperature stimulation by Dill and Keeney in 1978. 2 Acetic acid [3][4][5][6][7][8][9][10][11][12][13] and formic acid [6][7][8][9]12,14 have been used extensively in stimulation treatments in recent years. The application of organic acids in Saudi Arabia was first reported by Nasr-El-Din et al and Hashem et al, 8,15 where a mixture of acetic acid (5 wt%) and hydrochloric acid (5 wt%) was successfully used to stimulate water supply and injection wells in a sandstone field in central Saudi Arabia.…”

Section: Introductionmentioning

confidence: 99%

Development and Field Application of a New Measurement Technique for Organic Acid Additives in Stimulation Fluids

2005

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Formic and acetic acids, with and without HCl, have been used extensively over the last 40 years as stimulation fluids and as acid additives. A measurement method for these organic acids was not previously available for highly contaminated acid stimulation samples that contain high acid concentrations, dissolved oil, suspended solids, and several different acid additives. Citric and acetic acids are also used in acid treatments as iron control agents at temperatures less than 200 and 150°F, respectively. An analytical method using capillary electrophoresis was developed to simultaneously measure the concentrations of formic and acetic acids in stimulation fluids. The developed method was used to evaluate flowback samples from pickle treatments and stimulation treatments of several high-temperature wells.The following conclusions are made: • A method for the simultaneous measurement of formic and acetic acids was developed, evaluated, and implemented for acid stimulation samples.• Citric acid concentration can be determined in certain cases, which are identified in the paper.• Results of formic and acetic acid concentrations in sandstone and carbonate corefloods were evaluated.• Flowback samples from pickle treatments and acid fracture treatments were evaluated. Results from treatments of super chrome-13 and low-carbon steel tubing with 15 wt% HCl/ 9 wt% formic acid show that a small decrease in formic acid relative to chloride concentration occurred over time with carbon steel. No significant decrease of formic acid relative to chloride concentration was observed in the flowback of a well with a super chrome-13 completion.

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Acidizing Gas Wells in the Merluza Field Using an Acetic/Formic Acid Mixture and Foam Pigs

Cited by 28 publications

References 0 publications

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

High-Viscosity-Yield Acid Systems for High-Temperature Stimulation

Development and Field Application of a New Measurement Technique for Organic Acid Additives in Stimulation Fluids

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