Hydraulic fracturing (HF) is currently the most widespread and effective method of oil production stimulation. The most commonly used fracturing fluid is crosslinked guar gels. However, when using these systems, problems such as clogging of the pore space, cracking, and proppant packing with the remains of the undestroyed polymer arise. Therefore, the efficiency of the hydraulic fracturing process decreases. In this work, compositions based on viscoelastic surfactants (VES) and synthetic polymers (SP) were considered as alternatives capable of minimizing these disadvantages. Most often, the possibility of using a composition as a fracturing fluid is evaluated using rotational viscometry. However, rotational viscometry is not capable of fully assessing the structural and mechanical properties of fracturing fluid. This leads to a reduced spread of systems based on VES and SP. This paper proposes an integrated approach to assessing the effectiveness of a water-based fracturing fluid. The proposed comprehensive approach includes an assessment of the main characteristics of water-based fracturing fluids, including an analysis of their structural and mechanical properties, which is based on a combination of rotational and oscillatory rheology and a comparative analysis of methods for studying the influence of fluids on the reservoir rock. The use of the developed approach to assess the technological properties of fracturing fluids makes it possible to demonstrate the potential applicability of new, unconventional fracturing fluids such as systems based on VES and SP.

In the last decade, hydrogels for hydraulic fracturing based on viscoelastic surfactants have been actively studied. Interest in these systems is justified by their unique qualities: good viscoelasticity and the ability to form stable suspensions of proppant or sand, destruction without the formation of bridging agents, hydrophobization of the rock surface and metal of technological equipment, as well as oil-cleaning properties. These qualities are most often provided by a minimum set of components—a surfactant and an electrolyte. However, the absence of a polymer limits the use of these gels in formations where fluid leakoff is possible. In this article, a liquid was studied, based on a pseudo gemini surfactant (PGVES) with the addition of a water-soluble polysaccharide. The objects of study were selected based on the assumption of interactions between PGVES and the polymer; interactions which favorably influence the technological characteristics of the fracturing fluid. To confirm the hypothesis, rheological studies were carried out. These included rotational viscometry and oscillatory studies at various temperatures. The settling velocity of particles of various proppant fractions was studied and tests were carried out to assess fluid leakoff. The performed experiments show an improvement in the characteristics of the PGVES-based gel under the influence of the polysaccharide. In particular, the rheological properties increase significantly, the stability of proppant suspensions improves, and the fluid leakoff of systems decreases, all of which expands the possibility of using these fracturing fluids and makes this area of experimentation promising.

This paper presents the laboratory synthesis of zwitterionic surfactant—oleylamido propyldimethylamine oxide (OADAO), as well as the selection of conditions for its implementation. The results of the analysis of synthesis products by potentiometric titration and IR-Fourier spectroscopy methods are presented, which prove the presence of the target product in the composition of the reaction mass at the end of synthesis. The positive results of the synthesis and the absence of light organochlorine compounds (LOC) in the end products allow us to further consider OADAO, for example, as a gelling agent for aqueous fracturing fluids, by studying its technological characteristics.