Low-salinity water and surfactants for hydraulic fracturing and EOR of shales

Teklu, Tadesse Weldu; Li, Xiaopeng; Zhou, Zhou; Alharthy, Najeeb; Wang, Lei; Abass, Hazim

doi:10.1016/j.petrol.2017.12.057

Cited by 65 publications

(41 citation statements)

References 12 publications

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“…This is consistent with the fact that slick water fracturing will have high salinity in the flowback water, an indirect indication of water's role in matrix fracturing, i.e., opening of the nanofluidic seals. Also, explained is that high salinity water could not open tight oil and gas pore throats [29], while fresh water and fluid with surfactant could [30].…”

Section: Discussionmentioning

confidence: 99%

Headspace Isotope & Compositional Analysis for Unconventional Resources: Gas in Place, Permeability and Porosity Prediction and Completions Planning

Tang

Lin

et al. 2020

Geosciences

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Cuttings/cores’ Headspace Isotope and Composition Analysis (HICA) provides an effective way to calculate the nano pore throat size and distributions much like nitrogen and CO2 adsorption BET/BJH analysis, and it could also provide information about the original pore pressure or gas in place. Tight gas and oil storage is different from conventional where a majority of oil and gas are stored in nanometer sized pores (nanopores). Therefore the nanofludics, i.e., nanometer scale capillary sealing and opening in nanopores of tight rocks, plays a key role in overpressure conservation and storage of oil and gas, and also the fracing process involves the opening of the nano pore capillary seals through rock-fluid interactions. The rock-fluid nanofluidics interactions during fracing could also be studied through HICA and the results could help the optimization of fracing designs.

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Section: Discussionmentioning

confidence: 99%

Headspace Isotope & Compositional Analysis for Unconventional Resources: Gas in Place, Permeability and Porosity Prediction and Completions Planning

Tang

Lin

et al. 2020

Geosciences

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“…The osmotic effect can also contribute to the enhanced oil recovery (EOR) mechanism of unconventional shale formations. Recent studies show that low-salinity waterflooding EOR is can significantly improve oil production from shale formations, especially in highsalinity tight shale formations [8,[101][102][103][104]. The concept is to enhance osmotic flow through a smaller salinity of waterflooding fluid than that of formation fluid.…”

Section: Osmosismentioning

confidence: 99%

“…The application also depends on membrane efficiency. Fakcharoenphol et al [8] and Teklu et al [102] proved in clay-rich tight formations that osmosis can improve oil displacement under low-salinity fluid. Figure 5 shows experimental results of osmosis effect on oil displacements based on authors' work.…”

Section: Osmosismentioning

confidence: 99%

A Critical Review of Osmosis-Associated Imbibition in Unconventional Formations

Zhou

Teklu

2021

Energies

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In petroleum engineering, imbibition is one of the most important elements for the hydraulic fracturing and water flooding processes, when extraneous fluids are introduced to the reservoir. However, in unconventional shale formations, osmosis has been often overlooked, but it can influence the imbibition process between the working fluid and the contacting formation rocks. The main objective of this study is to understand effects of fluid–rock interactions for osmosis-associated imbibition in unconventional formations. This paper summarizes previous studies on imbibition in unconventional formations, including shale, tight carbonate, and tight sandstone formations. Various key factors and their influence on the imbibition processes are discussed. Then, the causes and role of osmotic forces in fluid imbibition processes are summarized based on previous and recent field observations and laboratory measurements. Moreover, some numerical simulation approaches to model the osmosis-associated imbibition are summarized and compared. Finally, a discussion on the practical implications and field observations of osmosis-associated imbibition is included.

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“…Since the first hydraulic fracturing well was constructed in 1947, hydraulic fracturing has always been used to establish a high-speed flow channel to increase oil and gas production and injection [33,34]. At the later stage of oilfield development, it is difficult to effectively use the dispersed remaining oil in medium-low permeability reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Study on Micro Displacement Mechanism of Hydraulic Fracturing by Oil Displacement Agent at High Pressure

Wang

Liu

et al. 2021

Geofluids

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The type-III oil formations in Daqing Oilfield are the representatives of medium-low permeability reservoirs in ultrahigh water cut oilfields of China, which is characterized by bad connectivity of pores and throats, dispersed residual oil distribution, and difficult to displace effectively. In order to produce the residual oil, we propose a new EOR (enhanced oil recovery) method which is hydraulic fracturing by an oil displacement agent at high pressure. In this paper, firstly, we have performed three sets of displacement experiments under different conditions to provide the basis for the analysis of changes in core pore structure and wettability. Next, overburden pressure porosity and permeability tests were used to analyze the effect of the injection of an oil displacement agent at high pressure on core physical properties. Correspondingly, the constant speed mercury injection tests were used to determine the radius distribution of pore throat and change of seepage resistance under different displacement conditions. Moreover, the scanning electron microscopy (SEM) tests of cores were carried out to observe and analyze changes in pore-throat size and connectivity, mineral particle accumulation, and cementation before and after hydraulic fracturing by an oil displacement agent at high pressure. Finally, core wettability tests were conducted to discuss and analyze the rule of core wettability change in hydraulic fracturing by an oil displacement agent at high pressure, and its mechanism of wettability changes. Research shows that increasing the formation energy is the most important mechanism of EOR by a fracturing-seepage-displacement method. Additionally, the type of an oil displacement agent has less effect. After an oil displacement agent at high pressure is injected to fracture the formation, it not only provides efficient flow channel and larger sweep volume for an oil displacement agent. Under the flushing action of high-pressure injection fluid, the original way of line or point contact between mineral particles gradually changes to free particles. Therefore, the pore throat size increases, some larger pores are formed, and the overall flow resistance decreases. After the injection of fluid at high pressure, the energy in formation has increased and the core wettability changes from oil-wet to weakly water-wet. This is not only because the residual oil on the pore surface is flushed by high pressure; in addition, the adsorption of an oil displacement agent on the rock surface reduces the liquid-solid interface energy and changes the wettability, thus improving the oil displacement efficiency.

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Low-salinity water and surfactants for hydraulic fracturing and EOR of shales

Cited by 65 publications

References 12 publications

Headspace Isotope & Compositional Analysis for Unconventional Resources: Gas in Place, Permeability and Porosity Prediction and Completions Planning

Headspace Isotope & Compositional Analysis for Unconventional Resources: Gas in Place, Permeability and Porosity Prediction and Completions Planning

A Critical Review of Osmosis-Associated Imbibition in Unconventional Formations

Study on Micro Displacement Mechanism of Hydraulic Fracturing by Oil Displacement Agent at High Pressure

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