With dwindling resources and mushrooming energy demands worldwide, HPHT field development has come under the limelight of the industry. Thus for expanding the existing horizons, new frontiers in HPHT stimulation advancements are being anticipated for economical harnessing of hydrocarbons. From more than a decade, surfactant fluids had been extensively employed in completion and stimulation operations as the surfactants arrange anatomically to form very long worm-like micelles, maintaining considerably low formation damage levels, and simultaneously exhibiting brilliant rheological properties, viscosity and proppant transportability. High fluid leak off and its inability to withstand temperatures greater than 200°F, have limited its HPHT application. Similar is the case for proppants where significant advancements have been made to increase its strength, but with better strength it has become heavier, causing early screenout, making it unable to reach deeper-complex fractures and requiring more viscous fluids.
This paper discusses in detail an extensive review of the application of nanoparticle and hydrogel polymer technology to enhance fluid – proppant performance in conditions with temperatures nearing 275°F and brine density up to 14.4ppg. This can be achieved by developing nano-sized crystals, which colligate with VES rod-like micelles to yield a virtual viscous filter cake that significantly curbs the fluid loss rate, thus demonstrating wall building on the porous media, rather than usual viscosity dependant leak off control. When internal breakers are applied, VES micelle structures degrade rapidly, leaking off VES fluid and the pseudo filter cake will then split into brine and nanoparticles, thus producing formations remains intact. To augment its performance proppants can be encapsulated with a thin hydrogel polymer layer which will hydrate on coming in contact with water. This layer smoothens the proppant, adsorbs the fines, and makes the proppant self-suspending. This wonder layer is resilient to high pressure high temperature conditions and exhibits excellent characteristics which are elucidated in this paper.
When applied, nanotechnology can reduce requirement of VES fluid volume by 60% and permeability range of VES fluid application is extended upto 2000md. While the incorporation of self-suspending proppants (SSP) can significantly bring down the requirement of additives and enable fracturing of challenging formations with maximum retained conductivity.