Performance Evaluation of Water Control with Nanoemulsion as Pre-pad Fluid in Hydraulically Fracturing Tight Gas Formations

Abstract

Experimental techniques have been developed to evaluate performance of nanoemulsions as pre-pad fluid for reducing water-cut in tight gas formations with multistage hydraulic fractures. More specifically, an aminopolysiloxane nanoemulsion was prepared and formulated in the laboratory for effective and efficient water control. The water-control mechanisms of nanoemulsions as pre-pad fluid in hydraulic fracturing were identified by performing the scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), spontaneous imbibition tests, and wettability measurements. The SEM and XPS tests confirm that certain changes occur in the element compositions and microstructure of the core surface before and after introducing the prepared nanoemulsions on the reservoir rock surface. Such changes irreversibly alter its wettability, indicated by the measured contact angle from 75°to 128°. During the displacement experiments, there exists a disproportionate permeability reduction on relative permeability of the gas−water systems. Gas relative permeability has only a small decline by less than 20% at different water saturations, while water relative permeability is reduced up to 60%. In addition, effective gas permeability for the core samples treated with nanoemulsions can be rapidly restored by the potential acid hydrolysis. This leads to not only creating new paths for gas flow in hydraulic fractures or invaded zones but also reducing the inertial resistance of gas flow in porous media by nanoemulsion retention.

Experimental Study on the Stability of a Novel Nanocomposite-Enhanced Viscoelastic Surfactant Solution as a Fracturing Fluid under Unconventional Reservoir Stimulation

“…The settlement rates (Equation ( 1)) were measured by the weighing method with a precision balance (the accuracy was 0.0001 g; Shanghai Fangrui Instrument CO., LTD., Shanghai, China). In this test, the settled NCs were separated from the liquid phase by a magnet as seen in Figure 1a-(2), while the magnet did not suck out the unsettled particles in the system as seen in Figure 1a- (1). Additionally, the effect of various factors on the settlement stability of NC-VES were studied by changing the nanoparticle concentration, shear rate, temperature and pH.…”

“…In recent years, unconventional oil and gas resources, especially shale gas and tight oil, have become an important part of the world energy landscape and a substitute resource for conventional oil and gas [ 1 , 2 , 3 , 4 , 5 ]. Hydraulic fracturing technology is one of the key technologies for the efficient development of unconventional reservoirs [ 6 , 7 , 8 ].…”

Characteristics and pH-Responsiveness of SDBS–Stabilized Crude Oil/Water Nanoemulsions

“…Nanoemulsions have the potential to reduce IFT and, accordingly, the capillary pressure of the reservoir [ 1 ], improve rock wettability [ 1 ], ease the fracturing fluid flow-back [ 21 ], eliminate phase trapping [ 21 , 22 ], and increase the regained gas permeability [ 1 , 21 ]. Accordingly, some researchers have recently demonstrated the applicability of nanoemulsions in enhanced oil recovery (EOR) [ 23 , 24 , 25 ], production enhancement (e.g., well stimulation and remediation, well-bore cleaning, and formation fracturing) [ 26 , 27 , 28 ], and pumping of extra heavy crude oil [ 29 ]. For instance, it has been reported that nanoemulsions can (i) minimize/control water-cut [ 28 ], (ii) create new channels for gas flow (i.e., increase gas permeability) [ 28 ], (iii) increase proppant permeability and, accordingly, lower the initial cleanup pressure [ 30 ], (iv) reduce fingering [ 31 ], (v) enhance the flow-back rates of fracturing fluids [ 31 ], (vi) reduce/eliminate water blocking problems [ 27 ], and (vii) minimize surfactant adsorption to the reservoir rocks [ 1 ], among other beneficial effects.…”

Application of microwave heating with iron oxide nanoparticles in the in‐situ exploitation of oil shale

“…Pad fluid, slurry fluid and displacing fluid consist of fracturing fluid. The difference among three fluids is that pad fluid does not carry proppant but creates main fractures . According to the relative low performance requirement of pad fluid, nanoparticles are suited to be mixed with foamed pad fluid and pumped together into the formation.…”

“…The difference among three fluids is that pad fluid does not carry proppant but creates main fractures. 25 According to the relative low performance requirement of pad fluid, nanoparticles are suited to be mixed with foamed pad fluid and pumped together into the formation. Base on above investigations and researches, the aqueous dispersion of iron oxide nanoparticles in this study was used to enhance the heating efficiency of microwave irradiation and stabilize foamed pad fluid at the same time.…”