Carbonate Acidizing and Flowback Analysis- A Review and an Evaluation Method

Aldakkan, Bashayer; Moajil, Abdullah M. Al; Alnoaimi, Khalid

doi:10.2118/191017-ms

Cited by 7 publications

(1 citation statement)

References 29 publications

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“…In general, HCl is widely used to enhance the permeability of carbonate rich shale and carbonate formations. Eagle Ford shale and Marcellus shale are typical examples of carbonate rich shale . The rate of reaction of HCl is faster at a higher temperature and almost double in the case of limestone at 60 °C as compared to that at the room temperature (27 °C). , In some cases, HF is used to stimulate the reservoir formation as well .…”

Section: Introductionmentioning

confidence: 99%

Impact of HCl Acidizing Treatment on Mechanical Integrity of Carbonaceous Shale

Abdulraheem

2022

ACS Omega

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Hydrocarbon production from unconventional resources especially shale reservoirs has tremendously increased during the past decade. Eagle Ford shale formation is one of the major sources of oil and gas in United States. However, due to extremely low permeability of this formation, stimulation treatments are implemented for hydrocarbon production. Eagle Ford shale requires a very high breakdown pressure during fracturing treatment due to high mechanical strength and low permeability. This study aims to address these challenges through applying the acidizing treatment on the shale and studying its impact. A detailed experimental investigation was carried out in this work to evaluate mechanical integrity and mineralogical and morphological changes of the shale formation when exposed to HCl acidizing treatment. Two crucial aspects of acidizing treatment, that is, impact of acid concentrations and treatment time, were given additional focus in this study. Different parameters such as porosity, nanopermeability, uniaxial compressive strength (UCS), acoustic velocities, dynamic elastic parameters, rock surface hardness (RSH) and brittleness index (BI) were analyzed before and after the acidizing treatment for different HCl concentrations. Microimaging was done through scanning electron microscopy (SEM) and whole cores were scanned using medical computed tomography (MCT) to understand the small-scale features. X-ray diffraction was used for the minerals’ identification. A continuous profile of UCS was measured through the scratch test system. Post-treatment results revealed that HCl treatment has a profound impact on rock mechanical properties of Eagle Ford shale. Considerable mass loss in core plugs was recorded after treatment at each concentration. Mineralogical composition and microimaging revealed compositional changes and porosity enhancement after the treatment. Reaction rate is higher in the first 10 min for higher acid concentrations resulting in significant changes in properties in that time interval. UCS and RSH exhibited a progressive decrease with increasing concentrations. The rate of RSH reduction increased with the increase in acid concentration nonlinearly. Acoustic velocities exhibited a considerable decrease even at low acid concentrations due to the enhancement of pore spaces. Noticeable reduction was observed in dynamic rock stiffness and BI with the increase in acid concentrations. On the contrary, Poisson’s ratio showed a significant increment. Experimental findings of this research can be used to optimize the acidizing treatment for Eagle Ford shale and other similar formations. Formation breakdown pressure can be reduced significantly by applying the acid treatment to improve the production of hydrocarbons. Furthermore, a better understanding of matrix acidizing can lead to savings in time and resources during production operations.

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Section: Introductionmentioning

confidence: 99%

Impact of HCl Acidizing Treatment on Mechanical Integrity of Carbonaceous Shale

Abdulraheem

2022

ACS Omega

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Sustaining Wormholes Mechanical Stability in Weak Acidized Carbonates Using Consolidants

et al. 2023

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Investigating the effect of matrix acidizing injection pressure on carbonate-rich Marcellus shale core samples: an experimental study

Khalil

Emadi

Altawati

2020

J Petrol Explor Prod Technol

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Near-wellbore damage, which significantly reduces hydrocarbon production, can happen during drilling, cementing, perforation, completion, and stimulation operations. The most common technique to remove or bypass this damage is matrix acidizing. The effects of matrix acidizing injection pressure on acid penetration rate, chemical reaction rate, solubility, porosity, and permeability of Marcellus core samples were investigated in this experimental study. To achieve a successful acid treatment, acid type and concentration must be carefully selected. The results of the X-ray powder diffraction (XRD) and the solubility test revealed that 15 wt.% hydrochloric acid (HCl) is the optimum acid. Matrix acidizing treatments were implemented on nine core samples, taken from Marcellus (shale gas reservoir), at the reservoir temperature (66 °C), confining pressure of 10.35 MPa, and three different acid injection pressures (1.72, 3.45, and 5.17 MPa). The results showed that performing acid treatments on the samples containing continuous carbonate layers created highly permeable channels (wormholes) resulting in significant improvement, up to 3900%, in the permeability of the samples. Additionally, the results of the acid penetration rate, chemical reaction rate, solubility, porosity, and permeability revealed that increasing the acid injection pressure resulted in increases in the aforementioned properties of the samples. The results also revealed that any increase in the injection pressure above 3.45 MPa did not demonstrate any significant enhancements in the properties of the samples. The results of the XRD analysis revealed that matrix-acidizing treatments dissolved 23.2% of calcite and 0.4% of dolomite existed in the samples.

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Carbonate Acidizing and Flowback Analysis- A Review and an Evaluation Method

Cited by 7 publications

References 29 publications

Impact of HCl Acidizing Treatment on Mechanical Integrity of Carbonaceous Shale

Impact of HCl Acidizing Treatment on Mechanical Integrity of Carbonaceous Shale

Sustaining Wormholes Mechanical Stability in Weak Acidized Carbonates Using Consolidants

Investigating the effect of matrix acidizing injection pressure on carbonate-rich Marcellus shale core samples: an experimental study

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