Development of Antifreeze Fracturing Fluid Systems for Tight Petroleum Reservoir Stimulations

Abstract

Most newly developed oil fields worldwide are ultralow permeability reservoirs, especially the Bakken and Eagle in North America as well as the Erdos and Jimusar in China. Therefore, the technology of stimulated reservoir volume (SRV) has become a critical method to improve hydrocarbon production. However, field operations in the winter season are usually confronted with numerous difficulties. For instance, conventional water-based fracturing fluid and liquid additives are easy to freeze up, and therefore, the gelation performance will be compromised. Accordingly, based on the application performance analysis of current antifreeze additive application status in many fields, several different inorganic salts and alcohols as antifreeze additives were selected. In this study, the formula of the antifreeze fracturing fluid system was designed and optimized based on the evaluations of the addition of different types of antifreeze candidates on the fracturing fluid performance. Results showed that when the environmental temperature was above −15 °C, alcohols (e.g., tetraethylene glycol) and inorganic salts with low concentrations could be employed as an antifreeze and they had nearly no negative effect on the viscosity and the cross-linking performance of the fracturing fluid. In this circumstance, the optimum composition was 0.2% hydrocarbon propyl guar gum, 0.2% borax, 1%MJ-1, and 0.5% tetraethylene glycol. In addition, when the environmental temperature is below −20 °C, the freezing resistance in the aqueous solution of alcohols was limited. At this time, NaCl with mass ratio higher than 15% showed the best antifreezing effect. However, the large amount of addition of inorganic salts would significantly reduce the viscosity of the fracturing fluid. The optimal concentration of guar gum in the antifreeze fracturing fluid system should increase to 0.4%, and the optimal concentration of borax was 0.3%. In addition, 0.1− 0.5% tetraethylene glycol can also be used as an antifreeze if the operation time is less than 6 h. The development of this antifreeze fracturing fluid can further elongate the current fracturing time in winter. Moreover, the experimental results can provide a guide for the field fracturing fluid operation and application.

Advances in Cryopreservatives: Exploring Safer Alternatives

“…1,2 Methanol and ethanol also have good properties by reducing freezing point within industrial applications instead of cellular cryoprotectants 15 as well as other glycols. 16 As this group of CPAs has been widely used to preserve different kind of cells, they have also been as reference to check or validate the effectiveness of emerging substances with this purpose, as is widely shown further on. (b) Sulfoxides and amides.…”

“…They have been shown to be effective cryoprotectants for a variety of cell types. A major advantage of this group is that they are relatively inexpensive and readily available, making them ideal for large-scale cell preservation efforts. , Methanol and ethanol also have good properties by reducing freezing point within industrial applications instead of cellular cryoprotectants as well as other glycols . As this group of CPAs has been widely used to preserve different kind of cells, they have also been as reference to check or validate the effectiveness of emerging substances with this purpose, as is widely shown further on. Sulfoxides and amides.…”

Insights on production mechanism and industrial applications of renewable propylene glycol

“…Recent experimental studies show that propylene glycol-based antifreeze is a suitable alternative to ethanol for preserving macroinvertebrate DNA from bulk-benthos DNA samples ( Robinson et al., 2021 ). In another study, RPG has been evaluated as potential antifreeze for water-based fracturing fluid and liquid additives in newly developed oil fields ( Wu et al., 2021 ). Study by Perez et al., (2019) shows that propylene glycol is a cryoprotective agent that could be used as a promising ingredient for treating cellular tissues and organs to prevent ice crystal’s formation at low temperatures ( Perez et al., 2019 ).…”

Development of Nanomontmorillonite-Reinforced Terpolymer Gels for High-Temperature Petroleum Reservoirs

“…8−10 Among them, in situ cross-linked polymer gels are widely used in water management operations in high water-cut petroleum reservoirs due to their controllable gelation time and gel strength, simple injection equipment, low cost, etc. 11 The in situ cross-linked polymer gel system mainly includes a metal (chromium, 12−14 zirconium, 15,16 aluminum, 17 etc.) cross-linked polymer gels, aldehyde or phenolic resin crosslinked polymer gels, 1 and polyethylenimine (PEI) cross-linked polymer gels.…”

“…Commonly used chemical plugging systems mainly include in situ cross-linked polymer gels, particle gels, and foam gels. − Among them, in situ cross-linked polymer gels are widely used in water management operations in high water-cut petroleum reservoirs due to their controllable gelation time and gel strength, simple injection equipment, low cost, etc . The in situ cross-linked polymer gel system mainly includes a metal (chromium, − zirconium, , aluminum, etc.) cross-linked polymer gels, aldehyde or phenolic resin cross-linked polymer gels, and polyethylenimine (PEI) cross-linked polymer gels. , Among them, metal cross-linked polymer gels are mainly suitable for oil reservoirs with a formation temperature below 90 °C due to their short gelation time at high temperatures and easy dehydration. , The toxicity of aldehyde and phenolic resin is very high and has been gradually restricted in recent years.…”