Enhancing Gas and Oil Production With Zeta Potential Altering System

Abstract

This paper describes laboratory studies and field results of a Zeta Potential Altering System (ZPAS) used in hydraulic fracturing treatments. Laboratory and field results show ZPAS minimizes proppant flow back, controls fines migration, enhances fluid load recovery, and inhibits calcium carbonate scale formation. This system, based on an inner salt, modifies the zeta potential of particles such as frac sand and formation substrate, changing the charge towards neutral values and therefore enhancing particle agglomeration. A variety of oil and gas formations can be treated by incorporating the new chemical additive into stimulation fluids. The chemical additive can be applied on the fly using several fluid systems to deliver the product. It is capable of treating proppants such as white and brown sand as well as ceramic proppants in any mesh size allowing flexibility in treatment design. A multi-well comparison of fractured wells, treated with ZPAS and of offset wells without the chemical, has been made in the Des Moines Granite Wash formation of the Texas Panhandle. In this study, results show wells treated with ZPAS had no significant proppant flowback compared to non-treated wells. In one case, a significant difference in production was observed from the ZPAS treated well compared to the untreated well. IntroductionProppant flowback following hydraulic fracturing treatments has been an issue in several regions for the oil and gas industry 1-3 . Proppant flowback is related to the conditions of the field, formation stresses, and the fracture treatment itself. Stimulating a formation with a hydraulic fracture creates a conductive path from the wellbore by placing proppant into the formation extending the effective wellbore radius. If proppant placed during a fracture treatment flows back, the resulting problems can range from sanding off a submersible pump to erosion damage of down hole and surface equipment. Cleaning up produced sand is an added cost to operations and there is the additional cost due to lost production which can not be recovered until the end of the life of that well. The cost associated with cleaning out the proppant flowback ranges in price depending on the type of clean up required, therefore it is necessary for operators to prevent the flowback of proppant whenever possible. Several different methods have been proposed and evaluated over the years.

Water-Rock Interaction for Eagle Ford, Marcellus, Green River, and Barnett Shale Samples

“…This results in zeta potential values of 15.01 mV and 13.33 mV for the water samples after the interaction with Green River and Barnett, respectively. Although this value is high compared to the other shale samples, the particles still may have a tendency to flocculate as particles begin to stabilize at an absolute zeta potential value greater than 20 mV [35]. Several studies also show the similar correlation of water samples with high amounts of divalent cations yielding low zeta potential values [31,33,36].…”

A Review on Chemical Sand Production Control Techniques in Oil Reservoirs

“…The zeta potential is the electrostatic potential between the particle surface in the fluid inside the colloidal suspension media. , In other words, the zeta potential is defined as the charge at the interface of the hydrodynamic boundary between the solid and fluid surfaces because of the related electrostatic repulsion force and the van der Waals gravitational force. Therefore, it is a function of the particles’ surface charge, adsorbed layers to the surface, and the type and chemical composition of the suspension medium. , Zeta potential is utilized in various industries such as corrosion inhibitors, separation in mining, paint, and petroleum…”

“…Therefore, it is a function of the particles' surface charge, adsorbed layers to the surface, and the type and chemical composition of the suspension medium. 97,98 Zeta potential is utilized in various industries such as corrosion inhibitors, separation in mining, paint, and petroleum. 99 One technique to prevent sand production is changing the zeta potential of sand particles so that they adsorb each other and cease being produced.…”

Quantitative characterization of polyacrylamide–shale interaction under various saline conditions

“…This created clusters of large particles to resist flow and lead to decrease in mobility and zeta potential (Yalçın et al 2002) increased the net positive charge of the medium, leading to the increase in zeta potential. Zeta potential values between -20 mV and 20 mV had an effective charge low enough for flocculation to occur (Johnson et al 2010). …”