scholarly journals CO2 Foam as an Improved Fracturing Fluid System for Unconventional Reservoir

Author(s):  
Shehzad Ahmed ◽  
Alvinda Sri Hanamertani ◽  
Muhammad Rehan Hashmet
2015 ◽  
Author(s):  
Jia Zhou ◽  
Paul Carman ◽  
Hong Sun ◽  
Richard Wheeler ◽  
Harold Brannon ◽  
...  

Abstract Post-treatment production analyses for hydraulic fracturing treatments with conventional crosslinked gel or slickwater often indicate that the treatments do not achieve the designed stimulation effectiveness, which could be attributed to non-optimal proppant placement and/or significantly damaged fracture conductivity. Although conventional crosslinked fluids are observed to provide good proppant suspension in laboratory environments, they might not provide the desired proppant transport under downhole conditions. Crosslinked fluids are known to be difficult to clean up, and thus are notorious for imparting gel damage to proppant pack and formation. Slickwater can be used to mitigate gel damage by reducing the effective polymer loadings, but consequential extreme proppant settling and banking problems reduce the chance of achieving fracture performance. Several proppant placement techniques have been developed to generate highly conductive paths for hydrocarbons to flow from an unconventional reservoir to the wellbore, such as hybrid fracturing, reverse hybrid fracturing, and channel fracturing, each of which predominantly rely upon high viscosity fluids to carry the proppant to the designated location. This paper presents a non-traditional fracturing fluid system and application technique with near perfect proppant suspension and transport, high fracture conductivity, and self-diverting characteristics. The revolutionary fracturing fluid system employs engineered packing of particle domains for proppant suspension mechanics that are significantly different from crosslinked polymer systems which use polymer chain overlap and inter-chain crosslinking to generate viscosity governed proppant transport. The unique gel particle structure perfectly suspends proppant for several hours at reservoir conditions to facilitate better transverse and vertical placement of proppant in the fracture and significantly increases the fractured surface area, which is one of most important factors in unconventional reservoir production. The self-diverting tendencies offer the potential to maximize created fracture area while simultaneously reducing the treating fluid volumes without the addition of costly diverting additives. The degradability of the fluid can be controlled at reservoir conditions by fluid pH and/or breaker loading to yield near 100% regained proppant pack conductivity. This paper discusses the evolution of the technology, and laboratory results for this unique fluid system. The system can unlock reservoir potential in areas requiring high fractured surface area and high regained conductivity, such as unconventional liquid-rich formations.


2015 ◽  
Vol 88 (11) ◽  
pp. 1884-1891 ◽  
Author(s):  
Siming Yan ◽  
Yongji Wang ◽  
Jia He ◽  
Hongdan Zhang

RSC Advances ◽  
2019 ◽  
Vol 9 (27) ◽  
pp. 15246-15256 ◽  
Author(s):  
Jinhao Gao ◽  
Guanghua Zhang ◽  
Lei Wang ◽  
Li Ding ◽  
Huaqiang Shi ◽  
...  

Surfactant and hydrophobic chains form a dense network structure, resulting in an improvement in the salt tolerance of the polymer.


2020 ◽  
Vol 10 (8) ◽  
pp. 3419-3436
Author(s):  
Kuangsheng Zhang ◽  
Zhenfeng Zhao ◽  
Meirong Tang ◽  
Wenbin Chen ◽  
Chengwang Wang ◽  
...  

Abstract When cold fluid is injected into low-temperature, low-pressure, low-permeability reservoirs containing wax-bearing heavy oil, cryogenic paraffin deposition and heavy oil condensation will occur, thus damaging the formation. Moreover, the formation pressure coefficient is low and the working fluid flowback efficiency is low, which affects the fracturing stimulation effect. Therefore, an in situ heat/gas clean foam fracturing fluid system is proposed. This system can ensure that conventional fracturing fluid can create fractures and carry proppant in the reservoir, generate heat in situ to avoid cold damage, reduce the viscosity, and improve the fluidity of crude oil. The in situ heat fracturing fluid generates a large amount of inert gas while generating heat, thus forming foam-like fracturing fluid, reducing fluid loss, improving proppant-carrying performance, improving gel-breaking performance, effectively improving crack conductivity, and is clean and environmentally friendly. Based on the improved existing fracturing fluid system, in this paper, a new type of in situ heat fracturing fluid system is proposed, and a system optimization evaluation is conducted through laboratory experiments according to the performance evaluation standard of water-based fracturing fluid. Compared with the traditional in situ heat fracturing fluid system, the fracturing fluid system proposed in this study generates a large amount of inert gas and form foam-like fracturing fluid, reduces fluid loss, enhances the proppant-carrying capacity and gel-breaking performance, improves crack conductivity, the gel without residue and that the gel-breaking liquid is clean and harmless.


2020 ◽  
Author(s):  
Zhifeng Luo ◽  
Nanlin Zhang ◽  
Liqiang Zhao ◽  
Lin Wu ◽  
Yuxin Pei ◽  
...  

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