A comprehensive method for acid diversion performance evaluation in strongly heterogeneous carbonate reservoirs stimulation using CT

Cao, Chong; Zhou, Fujian; Cheng, Linsong; Liu, Shuang; Lu, Wenpei; Wang, Qing

doi:10.1016/j.petrol.2021.108614

Cited by 17 publications

(8 citation statements)

References 17 publications

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“…These agents can temporarily plug the high-permeability zones of the formation, thus diverting the fluid to the low-permeability zones. In recent years, the use of diverting acids like emulsified and foam-based acids has been found to be successful [27]. Thus, the use of self-diverting agents (SDA) like in-situ crosslinked acid (ICA) and viscoelastic diverting agents (VDA) has been widely studied for their beneficial characteristics.…”

Section: Heterogenous Formationsmentioning

confidence: 99%

“…When looking at the core images in Table 2, the acid penetrated both the inlet and the outlet of the low-permeability core, but no penetration can be seen in the high-permeability core, showing that the acid was able to divert to the low-permeability core. For higher permeability contrast environments, a foam-based viscoelastic surfactant has been introduced that combines the plugging ability of a foam acid and the high viscosity of VES [27]. As stated before, effective plugging is necessary to temporarily block the high-permeability zone and direct the fluid to the low-permeability area.…”

Section: Tn-16235mentioning

confidence: 99%

“…A detailed study compared the behavior of foam acid, pure VES, and foam-based VES in parallel core flood tests with a large permeability contrast [27]. The foam acid was used in these experiments with the purpose of comparing it to the behavior of foam-based VES.…”

Section: Ves and Foam-based Vesmentioning

confidence: 99%

“…Steel is the main component of pipelines in well construction. Their types can range from mild steel (API N80, L80, J55) to high Cr-content corrosion resistant alloys (austenitic-ferritic steel and modified martensitic 13% Cr steel) [27] As HCl is not able to divert itself to the least permeable zones in the formations even at low-permeability contrasts, the use of chemical diverters has been found successful in the experimental research presented in this section. Comparing the results, the use of viscoelastic surfactants showed an effective diversion.…”

Section: Corrosive Environmentsmentioning

confidence: 99%

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Matrix Acidizing in Carbonate Formations

Chacon

Pournik

2022

Processes

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Matrix acidizing in carbonate reservoirs is a process that has been long used to increase productivity in oil and gas producing formations. The main goal is to create wormholes that bypass the damage in the formation. Hydrochloric acid (HCl) is the main acid used for this; however, it has several disadvantages that affect the success of these treatments. Its high reaction rate, inability to divert, and corrosive nature are a few of the reasons why research in this area has focused on finding alternative fluids. This paper discusses studies on successful alternatives to HCl. It has been observed that emulsified acids, which work with the addition of a surfactant to HCl, have shown positive results as their high viscosity allows them to retard the reaction rate between the acid and the rock and form effective and dominant wormholes. This is needed, especially in high-temperature environments. As HCl also lacks the ability to divert to low-permeability zones in highly heterogeneous formations, emulsified acids are also helpful for this task. While viscoelastic surfactants have been found to be less susceptible to form damage since they do not have any polymer content, their diversion performance has not been as effective as emulsified acids. Corrosion is one of the greatest and most expensive issues faced in matrix acidizing treatments. The use of corrosion inhibitors has been proposed as the best way to deal with this problem. Inorganic corrosion inhibitors are no longer an option as they are extremely toxic and pose a great danger to the environment. Organic corrosion inhibitors have been proposed as an alternative since the 1970s. However, organic compounds still pose a hazard in their use. Natural extracts as alternatives have been proposed for their inhibition ability. The use of henna extract and aqueous garlic peel extract as corrosion inhibitors has shown positive results with lower corrosion rates compared to some conventional inhibitors.

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Section: Heterogenous Formationsmentioning

confidence: 99%

Section: Tn-16235mentioning

confidence: 99%

Section: Ves and Foam-based Vesmentioning

confidence: 99%

Section: Corrosive Environmentsmentioning

confidence: 99%

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Matrix Acidizing in Carbonate Formations

Chacon

Pournik

2022

Processes

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“…With the development of unconventional petroleum resources, tight oil reservoirs occupy an increasingly important position in the petroleum industry. , Compared with conventional reservoirs, tight reservoirs have smaller pores, and the proportion of micro-/nanopores increases significantly. , Due to the extremely poor reservoir conditions, the development of tight oil reservoirs still faces some problems, resulting in the low efficiency of oil exploitation. − Many studies demonstrate that imbibition is an important oil recovery mechanism during the process of water injection development for tight reservoirs. − For tight reservoirs with artificially hydraulic fractures or natural fractures, strong capillary pressure is caused by a small pore throat, which induces spontaneous countercurrent imbibition of water into the tight matrix at water-wet conditions. − …”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of Nonlinear-Diffusion Countercurrent Imbibition for Porous Medium with Micro-/Nanopores

Chen

et al. 2022

Energy Fuels

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Countercurrent imbibition is an important oil recovery mechanism in tight reservoir development. For tight oil reservoirs with hydraulic fractures and natural fractures, the injected fluid imbibes into a tight matrix from the fracture surface while crude oil flows reversely into the fracture during the process of liquid injection and soaking. Based on the traditional imbibition model, this paper proposes a countercurrent imbibition extension model for porous medium with micro-/nanopores, considering the early superdiffusion phenomenon under low water saturation. The reliability of this proposed model is further verified through experimental imbibition data and compared with the classical imbibition model. This model can obtain the dynamic evolution process of the imbibition saturation profile and quantify the countercurrent imbibition distance (imbibition range). The sensitivity analysis is then conducted, including the imbibition time, core length, characteristic parameters of relative permeability, characteristic parameters of capillary pressure, oil viscosity, and permeability. The results demonstrate that the countercurrent imbibition process can be divided into three stages: the superdiffusion stage (faster than t 0.5), transition stage, and subdiffusion stage (slower than t 0.5). Two key parameters, the critical imbibition saturation and its corresponding critical imbibition time, can be obtained through this model, which are significant to establishing reasonable soaking time for achieving higher oil recovery. This research improves the understanding of the countercurrent imbibition process, which explores the efficient development of water injection for tight oil reservoirs with micro-/nanopores.

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