Abstract: A first type of coupon holder includes an elongated core that is axially aligned with a coupon holder axis and an external surface that circumscribes the elongated core. The external surface defines coupon mounting surfaces with different radial orientations relative to the coupon holder axis. The coupon mounting surfaces are circumferentially aligned around the elongated core and have geometric centers with the same axial position along the coupon holder axis. A second type of coupon holder includes an elongated support structure that is axially aligned with a coupon holder axis and a coupon holder body positioned to have an end face in a plane transverse to the coupon holder axis. The coupon holder body has a plurality of slots to receive end portions of coupons. The slots are in a circular arrangement around the coupon holder axis and position coupons in parallel to the coupon holder axis.

Abstract: A method of stimulating petroleum production includes introducing a fracturing fluid into a petroleum bearing carbonate formation, thereby creating at least one fracture to stimulate the petroleum production. The fracturing fluid is introduced into the petroleum bearing carbonate formation at a pressure above the breakdown pressure of the formation. The fracturing fluid includes a plurality of proppants where from 1 to 50 wt. % of the plurality of proppants includes micro proppants having a particle size ranging from 0.5 to 150 ?m, and from 50 to 99 wt. % of the plurality of proppants includes macro proppants having a particle size greater than 100 mesh.

Abstract: A method of stimulating petroleum production includes introducing a fracturing fluid into a petroleum bearing carbonate formation, thereby creating at least one fracture to stimulate the petroleum production. The fracturing fluid is introduced into the petroleum bearing carbonate formation at a pressure above the breakdown pressure of the formation. The fracturing fluid includes a plurality of proppants where from 1 to 50 wt.% of the plurality of proppants includes micro proppants having a particle size ranging from 0.5 to 150 µm, and from 50 to 99 wt.% of the plurality of proppants includes macro proppants having a particle size greater than 100 mesh.

Abstract: A method of stimulating petroleum production includes introducing a fracturing fluid into a petroleum formation, thereby creating at least one fracture to stimulate the petroleum production. The fracturing fluid is introduced into the petroleum formation at a pressure above the breakdown pressure of the formation. The fracturing fluid includes a plurality of proppants each including a proppant particle and a coating. The coating includes a hydrophobic coating, a cross-linked hydrogel, or both. From 1 to 50 wt. % of the plurality of proppants includes micro proppants having a particle size ranging from 0.5 to 150 ?m, and from 50 to 99 wt. % of the plurality of proppants includes macro proppants having a particle size of 100 mesh or greater.

Abstract: A method of stimulating petroleum production includes introducing a fracturing fluid into a petroleum formation, thereby creating at least one fracture to stimulate the petroleum production. The fracturing fluid is introduced into the petroleum formation at a pressure above the breakdown pressure of the formation. The fracturing fluid includes a plurality of proppants where from 1 to 50 wt. % of the plurality of proppants includes micro proppants having a particle size ranging from 0.5 to 150 ?m, and from 50 to 99 wt. % of the plurality of proppants includes macro proppants having a particle size greater than 100 mesh.

Abstract: A first type of coupon holder includes an elongated core that is axially aligned with a coupon holder axis and an external surface that circumscribes the elongated core. The external surface defines coupon mounting surfaces with different radial orientations relative to the coupon holder axis. The coupon mounting surfaces are circumferentially aligned around the elongated core and have geometric centers with the same axial position along the coupon holder axis. A second type of coupon holder includes an elongated support structure that is axially aligned with a coupon holder axis and a coupon holder body positioned to have an end face in a plane transverse to the coupon holder axis. The coupon holder body has a plurality of slots to receive end portions of coupons. The slots are in a circular arrangement around the coupon holder axis and position coupons in parallel to the coupon holder axis.

Abstract: Methods for performing a hydraulic fracturing operation are provided. The methods include pumping a hydraulic fracturing fluid through a wellbore into a subsurface formation, in which the hydraulic fracturing fluid comprises a plurality of proppants. Individual proppants of the plurality of proppants travel a first distance into the subsurface formation and have a persistent diameter homogeneity. The methods further include shutting in the wellbore to facilitate crushing individual proppants under formation pressure to form microproppants and resuming pumping the hydraulic fracturing fluid after crushing individual proppants and forcing the microproppants to a second distance within the subsurface formation, in which the second distance is beyond the first distance relative to the wellbore.

Abstract: Methods for performing a hydraulic fracturing operation are provided. The methods include pumping a hydraulic fracturing fluid through a wellbore into a subsurface formation, in which the hydraulic fracturing fluid comprises a plurality of proppants. Individual proppants of the plurality of proppants travel a first distance into the subsurface formation and have a persistent diameter homogeneity. The methods further include shutting in the wellbore to facilitate crushing individual proppants under formation pressure to form microproppants and resuming pumping the hydraulic fracturing fluid after crushing individual proppants and forcing the microproppants to a second distance within the subsurface formation, in which the second distance is beyond the first distance relative to the wellbore.

Abstract: Provided are systems and methods for determining fracture toughness of a subsurface geologic formation. Embodiments include collecting (from drilling fluid circulated into a wellbore during a drilling operation) a drill cutting generated by a drill bit cutting into a subsurface formation, preparing (from the drill cutting) a drill cutting specimen comprising a miniature single edge notch beam (SENB) having a specified length in the range of 1 millimeter (mm) to 100 mm, conducting a three-point bend testing of the drill cutting specimen to generate load-displacement measurements for the drill cutting specimen, and determining (based on the load-displacement measurements for the drill cutting specimen) a fracture toughness of the subsurface formation.

Abstract: Provided are systems and methods for determining fracture toughness of a subsurface geologic formation. Embodiments include collecting (from drilling fluid circulated into a wellbore during a drilling operation) a drill cutting generated by a drill bit cutting into a subsurface formation, preparing (from the drill cutting) a drill cutting specimen comprising a miniature single edge notch beam (SENB) having a specified length in the range of 1 millimeter (mm) to 100 mm, conducting a three-point bend testing of the drill cutting specimen to generate load-displacement measurements for the drill cutting specimen, and determining (based on the load-displacement measurements for the drill cutting specimen) a fracture toughness of the subsurface formation.

Abstract: A novel method of fabricating carbon nanotube sheet scrolled fiber and fiber tows (carbon, graphite, glass, natural polymer, synthetic polymer, metallic, silicon carbide, Kevlar, etc.) in composites with improved interfacial shear strength, compressive strength, yield strength, stiffness and toughness has been reported. Single or multiple layers of carbon nanotube sheet, with a bias/wrapping angle of 0° and 90°, has been scrolled around single fiber and fibers tows to improve the above mentioned mechanical properties of the matrix surrounding the fiber. Other common methods of growing CNTs directly on the fibers actually damage the fiber surface during the required precursor deposition and CNTs growth process. This demonstrated solid-state method overcomes such known problems. The CNTs sheet scrolled fiber is embedded into the polymer matrix exhibits significant (80%) increase in interfacial shear strength, compressive strength and toughness.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.

Abstract: A novel method of fabricating carbon nanotube sheet scrolled fiber and fiber tows (carbon, graphite, glass, natural polymer, synthetic polymer, metallic, silicon carbide, Kevlar, etc.) in composites with improved interfacial shear strength, compressive strength, yield strength, stiffness and toughness has been reported. Single or multiple layers of carbon nanotube sheet, with a bias/wrapping angle of 0° and 90°, has been scrolled around single fiber and fibers tows to improve the above mentioned mechanical properties of the matrix surrounding the fiber. Other common methods of growing CNTs directly on the fibers actually damage the fiber surface during the required precursor deposition and CNTs growth process. This demonstrated solid-state method overcomes such known problems. The CNTs sheet scrolled fiber is embedded into the polymer matrix exhibits significant (80%) increase in interfacial shear strength, compressive strength and toughness.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.

Abstract: Fabrication of yarns or other shaped articles from materials in powder form (or nanoparticles or nanofibers) using carbon nanotube/nanofiber sheet as a platform (template). This includes methods for fabricating biscrolled yarns using carbon nanotube/nanofiber sheets and biscrolled fibers fabricated thereby.