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

Welton, Thomas; Domelen, Mary Susan Van

doi:10.2118/98237-ms

Cited by 5 publications

(4 citation statements)

References 49 publications

(39 reference statements)

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“…More details on these coreflood tests were recently given by Welton and van Domelen. 24 The wormholes formed with gelled HCl/formic acid penetrate deeper compared to those formed with plain HCl because less acid spends on the wormhole wall and a larger fraction of the acid is transported to the tip of the wormholes. As a result, the wormholes are longer, but also narrower and therefore less conductive.…”

Section: -5 the Ungelled Hcl And Hcl/formic Blend In Figs 3 Andmentioning

confidence: 99%

Long-Term Comparative Evaluation of HCl/Formic Acid System Used To Stimulate Carbonate Formations at Severe Conditions in Saudi Arabia

et al. 2006

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe high levels of carbon dioxide and low levels of hydrogen sulfide content of some deep and high temperature gas producers contributed in the requirement to complete these wells using super Cr-13 tubings. Due to the low permeability of the formation and the associated formation damage issues, acid fracturing treatments were required to optimize the productivity of these wells. This paper describes the selection, optimization and long term comparative evaluation of the gelled and in-situ crosslinked HCl/formic acid systems used this type of wells. The high temperatures encountered in deep wells and the susceptibility of super Cr-13 to severe corrosion in high concentration HCl systems used for stimulation purposes added one additional difficulty to the acid stimulation process. To overcome these problems, extensive experimental and field studies were performed to select an acid system to enhance the productivity of these wells.Core flood tests performed with HCl/formic acid systems showed their ability to create deep wormholes in tight carbonate cores; however the corrosiveness of these systems at downhole conditions could be severe if the correct type and concentration of corrosion inhibitor is not used. In general, for the HCl/formic acid systems at downhole conditions (275°F) it was found that high concentrations of corrosion inhibitors are required to protect the super Cr-13 completions.Based on lab tests study acid stimulations were performed, the flow back fluid was recovered and analyzed to observe the corrosion problems and to optimize the corrosion inhibitor.In all the cases the wells responded very well to the acid stimulation and the completion integrity was not compromised in a short or long term. The paper also shows for the first time a comparative long term well response to the acid stimulation of the two acid systems used in the area, showing the better performance of the in-situ crosslinked HCl/formic system over the gelled HCl/formic system.

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Section: -5 the Ungelled Hcl And Hcl/formic Blend In Figs 3 Andmentioning

confidence: 99%

Long-Term Comparative Evaluation of HCl/Formic Acid System Used To Stimulate Carbonate Formations at Severe Conditions in Saudi Arabia

et al. 2006

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“…Although a gelled acid with a high viscosity can release hydrogen ions slowly, the accompanying results show that it is difficult for the acid to penetrate the deep places of low‐pressure and low‐permeability reservoirs because of its high viscosity. Secondary damage caused by the gelled acid is still apparent after acidization; this includes residual and gelled fluid breakdown problems . What is more, the gelling process is often meticulous and time consuming.…”

Section: Introductionmentioning

confidence: 99%

“…Secondary damage caused by the gelled acid is still apparent after acidization; this includes residual and gelled fluid breakdown problems. [5][6][7][8][9] What is more, the gelling process is often meticulous and time consuming. This is primarily due to the onsite blending and mixing of the base gel and the time that is necessary to produce a consistent base gel.…”

Section: Introductionmentioning

confidence: 99%

Copolymer MCJS as a retarder of the acid–rock reaction speed for the stimulation of deep carbonate reservoirs

Quan

Huang

et al. 2014

J of Applied Polymer Sci

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The fast reaction rate between hydrochloric acid and carbonates causes the most acid consumption near the wells, and the acid cannot penetrate the deeper places of the carbonate reservoir; this limits the application of acidizing modifications for the reservoir. In this study, we chose acrylamide, 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), allyl alcohol polyoxyethylene ether (APEG), and N-dimethyl-N-vinyl nonadecan-1-aminium chloride (DMAAC-18) to synthesize a quadripolymer (MCJS) that could reduce the reaction rate mentioned previously. The molecular structure of MCJS was characterized by Fourier transform infrared and 1 H-NMR spectroscopy. The molecular weight and molecular weight distribution of MCJS was determined by gel permeation chromatography. Carbonate rock was analyzed by X-ray diffraction and energy-dispersive X-ray spectroscopy. The retarding properties of the acid mixed with MCJS (MCJS acid) were investigated, and the resulting reaction rate between the acid and carbonate decreased obviously, even at a low viscosity. Scanning electron microscopy and core flood experiments showed that the MCJS could be adsorbed on the carbonate rock surface and form a hydrated film that delayed the reaction.

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“…A disadvantage associated with increasing the acid viscosity was formation of damage due to polymer entrapment or precipitation of crosslinker [20]. Polymer was a source of permeability reduction, especially in low permeability formations [21].…”

Section: Introductionmentioning

confidence: 99%

Propagation of Regular HCl Acids in Carbonate Rocks: The Impact of an In Situ Gelled Acid Stage

Gomaa

Nasr‐El‐Din

2011

Journal of Energy Resources Technology

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Recent laboratory and fleld studies indicated that polymer-based in situ gelled acids can cause formation damage. Coreflood experiments using single-stage and multistage acids were conducted at 250 °E. 15 wt. % regular HCI and 5 wt. % in situ gelled acid-based on Ee(UI) as a crosslinker were the acids that were used in this study. Propagation of acids and crosslinker inside 20 in. long cores was examined for the flrst time in detail. Stage volume and injection rate, which were the parameters that affect the propagating of various chemical species, were examined. Samples of the core effluent were collected and the concentrations of calcium, crosslinker, and acid were measured. Material balance was conducted to determine the amount of cross-liker that retained in the core. The results show that in situ gelled acid should be pumped at low injection rates. In situ gelled acid at low injection rate instantaneously plugged the tip of the wormhole and did not create additional wormholes inside the core. Therefore, when the flnal regular acid stage bypassed the gel, it started to propagate from nearly the last point that the flrst stage ended. In site gelled acid stage volume should not exceed 0.5 PV. No beneflts were gained by increasing the volume of in situ gelled acids. Retention of total iron in the core increased in multistage acid treatments, especially at low acid injection rates.

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

Cited by 5 publications

References 49 publications

Long-Term Comparative Evaluation of HCl/Formic Acid System Used To Stimulate Carbonate Formations at Severe Conditions in Saudi Arabia

Long-Term Comparative Evaluation of HCl/Formic Acid System Used To Stimulate Carbonate Formations at Severe Conditions in Saudi Arabia

Copolymer MCJS as a retarder of the acid–rock reaction speed for the stimulation of deep carbonate reservoirs

Propagation of Regular HCl Acids in Carbonate Rocks: The Impact of an In Situ Gelled Acid Stage

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