Optimization of Acid Fracturing with Unified Fracture Design

Ravikumar, Arjun; Marongiu-Porcu, Matteo; Morales, Adrián

doi:10.2118/177486-ms

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…Then, a correlation is used based on rock properties and dissolution profile to determine the fracture conductivity (i.e., permeability). − Once determined, the productivity enhancement due to acid fracturing can be estimated using analytical productivity models or reservoir simulators. An engineer can then create what-if scenarios to find the optimum design parameters (i.e., injection rate, acid type, treatment volume) that maximize productivity …”

Section: Introductionmentioning

confidence: 99%

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Mineralogy Impact on Acid Fracture Design in Naturally Fractured Carbonates

Aljawad

2023

ACS Omega

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The impacts of a natural fracture on the propagation of a hydraulic fracture has been extensively studied in the past decade. However, there were only minor attempts to understand the impact of natural fractures on acid distribution during acid fracturing. This study provides an understanding of the impact of natural fractures on acid fracturing designs in limestone and dolomite formations. A built-in-house model that solves fracture propagation, acid transport and dissolution, heat transfer, and reservoir productivity was utilized. A sensitivity analysis was conducted to investigate the impact of temperature, injection rate, and acid type. One of the significant differences between limestone and dolomite is the dissolution profile in the hydraulic fracture. The maximum dissolution happens close to the wellbore in limestone, but far from the wellbore in dolomite at low acid temperatures. Also, the hydraulic fracture in dolomite could have lower conductivity (i.e., permeability) compared to the intersecting natural fractures, which is not usually the case in limestone. Hence, the productivity enhancement by acid fracturing in limestone formation is higher than in dolomite. In general, natural fractures reduce productivity, and their negative impact is more significant in dolomite. The sensitivity study showed that the acid temperature significantly impacts fractured well productivity of dolomite, especially at high reservoir permeability where higher dissolution is desired. It is observed that the optimum injection rate that maximizes productivity is much higher in limestone than in dolomite. Also, acid retardation does not positively impact the productivity of dolomite compared to limestone; however, high viscosity might be needed to keep the hydraulic fracture open. This is the first study to reveal mineralogy's impact on acid fracture performance in naturally fractured carbonates.

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Section: Introductionmentioning

confidence: 99%

“…An engineer can then create what-if scenarios to find the optimum design parameters (i.e., injection rate, acid type, treatment volume) that maximize productivity. 9 …”

Section: Introductionmentioning

confidence: 99%

Mineralogy Impact on Acid Fracture Design in Naturally Fractured Carbonates

Aljawad

2023

ACS Omega

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“…Guo et al (2004) researched three-dimensional modeling of acid fracturing and optimization design, and they proposed a technique for achieving the maximum net present value [19]. Ravikumar et al (2015) presented a method to estimate the optimum length and conductivity using the UFD approach [20]. Ai et al (2018) coupled the fracture geometry optimization with treatment parameter optimization to maximize the dimensionless productivity index [21].…”

Section: Introductionmentioning

confidence: 99%

Pumping Schedule Optimization in Acid Fracturing Treatment by Unified Fracture Design

Lotfi¹,

Hosseini²,

Aftabi³

et al. 2021

Preprint

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Acid fracturing simulation is used widely to optimize carbonate reservoirs and improve acid fracturing treatment performance. In this study, a method was used to minimize the risk of the acid fracturing treatment. First, optimal fracture geometry parameters with UFD methods are calculated. After that, design components change as long as fracture geometry parameters reach their optimal values. The results showed a high flow rate needed to achieve optimal fracture geometry parameters with increasing acid volume. Sensitivity analysis was performed on controllable and reservoir parameters. It observed that a high flow rate should be applied for a low fluid viscosity to achieve the optimization goals. Straight acid reaches optimal conditions at a high flow rate and low volume. These conditions for retarded acids appear only at a low flow rate and high volume. The study of the acid concentration for gelled acid showed that as it increased, the flow rate and volume increased. Besides, for low permeability formation, a large fracture half-length and small fracture width are desirable. In this case, a higher flow rate will be required. The sensitivity analysis showed that the optimum flow rate and acid volume increase and decrease for the high Young's modulus. The effect of closure stress was also investigated and observed for a sample with high closure stress, low flow rate, and high acid volume are required.

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“…Guo et al researched three-dimensional modeling of acid fracturing and optimization design, and proposed a technique for achieving the maximum net present value [19]. A method was used to estimate the optimal length and conductivity using the UFD approach [20]. Ai et al coupled the fracture geometry optimization with treatment parameter optimization to maximize the dimensionless productivity index [21].…”

Section: Introductionmentioning

confidence: 99%

Pumping Schedule Optimization in Acid Fracturing Treatment by Unified Fracture Design

et al. 2021

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Acid fracturing simulation has been widely used to improve well performance in carbonate reservoirs. In this study, a computational method is presented to optimize acid fracturing treatments. First, fracture geometry parameters are calculated using unified fracture design methods. Then, the controllable design parameters are iterated till the fracture geometry parameters reach their optimal values. The results show higher flow rates are required to achieve optimal fracture geometry parameters with larger acid volumes. Detailed sensitivity analyses are performed on controllable and reservoir parameters. It shows that higher flow rates should be applied for fluids with lower viscosity. Straight acid reaches optimal conditions at higher flow rates and lower volumes. These conditions for retarded acids appear to be only at lower flow rates and higher volumes. The study of the acid concentration for gelled acids shows that both flow rate and volume increase as the concentration increases. For the formation with lower permeability, a higher flow rate is required to achieve the desired larger fracture half-length and smaller fracture width. Further investigations also show that the formation with higher Young’s modulus requires decreasing the acid volume and increasing the optimal flow rate, while the formation with higher closure stress requires increasing the acid volume and decreasing the flow rate.

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Optimization of Acid Fracturing with Unified Fracture Design

Cited by 7 publications

References 19 publications

Mineralogy Impact on Acid Fracture Design in Naturally Fractured Carbonates

Mineralogy Impact on Acid Fracture Design in Naturally Fractured Carbonates

Pumping Schedule Optimization in Acid Fracturing Treatment by Unified Fracture Design

Pumping Schedule Optimization in Acid Fracturing Treatment by Unified Fracture Design

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