The modern petroleum industry relies on water-based stimulation fluids to be injected to “free” up trapped oil/gas and move them out from underground reservoir formations to the production wells. Surfactants are “surface-active” chemicals that contain at least two functional groups: one is water-soluble component and another one is water-insoluble (oil-soluble) component.
Typically a surfactant is added to the well stimulation make-up water in order to alter the interaction of this injected fluid in a favorable manner with the oil, gas, and rock interfaces within the treated reservoir. For example, surfactants can increase the interaction between the water and oil by decreasing the oil-water interfacial tension (IFT), reduce the interfacial energy between the water and hydrocarbon gas by lowering the surface tension, and increasing the wetting of the reservoir rock surfaces by the surfactant containing water phase.
The addition of surfactants to fracturing fluids can help to improve (1) shale-oil recovery (CE-CRS technology); (2) fluid flow-back (CE-FB technology); and (3) prevent formation of damaging tight emulsions in-situ and in produced fluids post-stimulation (CE-NE technology).Photomicrograph of oil-in-water emulsion.
IMPROVED OIL RECOVERY
Surfactant additives in stimulation fluids for improved hydrocarbon recovery.
Accelerates the dewatering process from shale/rock surfaces to increase flowback rate.
Increases oil-water separation of fracturing fluids from well stimulation.
Friction reducers are typically high molecular weight polymers (5 to 30 million Dalton) that will uncoil when added in the aqueous solution to significant decrease pumping pressure losses in hydraulic fracturing operations. The most common friction reducers used in the energy production industry are based on anionic polyacrylamide or other copolymers of polyacrylamide combined with different monomers. A friction reducer can be in liquid form (either in an oil-based emulsion or in a water-based suspension) or in dry-powder form. Once added to stimulation fluids, rapid inversion and hydration is necessary for optimal field performance.
Our product line includes friction reducers that hydrate very quickly and so may be added successfully ‘on-the-fly’. Prior to use, detailed compatibility tests of the selected friction reducer with other additives in the stimulation fluid and brine compositions are recommended. Our laboratories routinely carry out these tests.
Laminar Like Flow
Increased flow rate due to ChemEOR friction reducer additive – deeper, better fractures
Turbulent Like Flow
Reduced flow rate due to having no friction reducer additive – shorter, poorer fractures
Gelling agents are used to increase the viscosity and/or carrying capacity of proppant for a fracturing fluid. These products are usually polysaccharides in their native or highly processed or derived form. Each gellant has a particular dosage window with respect to pH, crosslinker, breaker, total dissolved solids, hardness, temperature profile, etc.
In general, Guar crosslinked with boron makes soft healing gels whereas cellulosics and derivatives make hard high temperature non healing gels. Each products temperature range may be extended with chemical stabilizers. Guar being nonionic should be more tolerant of fluid variation, whereas anionic celluloses and guar derivatives are more sensitive but can work quite well in certain waters. All of these systems can be used as linear gels for low proppant loading or rapidly moving fluid design where velocity provides the bulk of proppant transport. Each gel system has a unique rheological profile which will also help with product selection.High pressure, high temperature rheometer with oscillatory test function.
Polymeric carbohydrates such as guar, guar derivatives or CMC to boost proppant carrying capacity of fluids.
Special polymers with controllable gelling functions.
Depending on the need of a well stimulation operation, a number of special chemical additive compounds are included in stimulation/fracturing fluids to improve efficiency and to reduce the risk of formation damage.
Additives that are commonly used include: clay stabilizers to prevent the clay swelling or migrating by the water-based stimulation fluids, biocides to suppress growth of undesirable bacterial, scale inhibitors to prevent or slow build-up of water-borne scales, and corrosion inhibitors and iron control agents to extend lifetime of pipelines, etc. ChemEOR has developed a series of high-performance additives to meet the demands of our customers.Temporary Clay Stabilizer prevents collapse of layered clays during hydraulic fractures.
Inorganic environmentally-friendly clay stabilizer additive in stimulation/fracturing fluids where clay control is required.
Specialized polymeric phosphorus-free additives for inhibition of CaCO3, CaSO4, BaSO4, and silicate scales.
High-performance additives for PPDs as well as paraffin and asphaltene inhibition.