Hydraulic Fracturing Process

Fracture treatments of horizontal shale gas wells are carefully controlled and monitored operations that are performed in stages. Lateral lengths in horizontal wells for shale gas development may range from 1000 feet to more than 5000 feet. Before beginning a treatment, the service company will perform 

This section is based on information contained in USDOE, Modem Shale Gas Development in the United States A Primer, U.S. Department of Energy, Washington, DC, 2009, pp. 55-59. 

Because of the length of exposed wellbore, it is usually not possible to maintain a downhole pressure sufficient to stimulate the entire length of a lateral in a single stimulation event (Overbey et al., 1988). Because of the lengths of the laterals, hydraulic fracture treatments of horizontal shale gas wells are usually performed by isolating smaller portions of the lateral. 

Guided by state oil and gas regulatory agencies—to ensure that a well is protective of water resources and is safe for operation—operators or service companies perform a series of tests. These tests are designed to ensure that the well, well equipment, and hydraulic fracturing equipment are in proper 

Example of a Single Stage of a Sequenced Hydraulic Fracture Treatment 

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A low-molecular-weight condensation product of hydroxyacetic acid with itself or compounds containing other hydroxy acid, carboxylic acid, or hydroxy-carboxylic acid moieties has been suggested as a fluid loss additive [164]. Production methods of the polymer have been described. The reaction products are ground to 0.1 to 1500 p particle size. The condensation product can be used as a fluid loss material in a hydraulic fracturing process in which the fracturing fluid comprises a hydrolyzable, aqueous gel. The hydroxyacetic acid condensation product hydrolyzes at formation conditions to provide hydroxyacetic acid, which breaks the aqueous gel autocatalytically and eventually provides the restored formation permeability without the need for the separate addition of a gel breaker [315-317,329]. 

The fluids which are used in the hydraulic fracturing process can be quite complex. Laboratory research and development on these fluids require many hours of rheology testing to discover suitable compositions and systems. To speed this process, an automated stimulation fluid rheology laboratory was constructed. In this paper, we describe the types of instruments which are used in this laboratory, the computer system, and how t.vr cal experiments are set up, run, and results stored and analyzed. In the accompanying paper (Part II), the focus is on the automation of one of the more complex Instruments in this laboratory. 

We discuss the suspensions used in well stimulation and hydraulic fracturing processes. The following sections pertain to various types of suspensions used in well stimulation and fracturing processes, their rheological characterization and hydraulic properties, behavior of suspensions in horizontal wells, a state-of-the-art review of proppant settling velocity and proppant transport in the fracture, presently available measurement techniques for suspensions and their merits, and, finally, a summary and conclusions on the use of suspensions in well stimulation. Future industry needs for better understanding of the complex behavior of suspensions are also mentioned in this section. 

HCl Molecular formula for hydrochloric acid, which can be used in diluted form in the hydraulic fracturing process to fracture limestone formations and to clean up perforations in coalbed methane fracturing treatments. 

To determine the potential impacts of hydraulic fracturing on drinking water resources under a variety of circumstances, the USEPA has selected seven case studies located in various formation locations across the country that the Agency believes will provide the most useful information. The study includes a review of published literature, analysis of existing data, scenario evaluation and modeling, industry studies, and case studies. Two perspective case studies, where the USEPA will monitor key aspects of the hydraulic fracturing process at future hydraulic fracturing sites, are located in... 

At the end of the hydraulic fracturing process, and when gels are employed, these must be destroyed to allow fluids to flow freely through the freshly fractured zones and benefit from the permeability improvements achieved by fracturing. Chemical or enzymatic gel breakers are employed for this purpose. Traditionally, enzymatic breakers operate under mildly acidic conditions at low temperatures, while oxidizing chemical breakers operate at moderate-to-high... 

Hydraulic fracturing is a technique to stimulate the productivity of a well. A hydraulic fracture is a superimposed structure that remains undisturbed outside the fracture. Thus the effective permeability of a reservoir remains unchanged by this process. The increased productivity results from increased wellbore radius, because in the course of hydraulic fracturing, a large contact surface between the well and the reservoir is created. 

In situ soil remediation with physical methods includes the in situ heating (in situ thermal treatment), ground-freezing, hydraulic fracturing, immobilization/stabilization, flushing, chemical detoxification, vapor extraction, steam extraction, biodegradation/bioremediation, electroosmosis/ electrokinetic processes, etc. 

Oil-field chemistry has undergone major changes since the publication of earlier books on this subject Enhanced oil recovery research has shifted from processes in which surfactants and polymers are the primary promoters of increased oil production to processes in which surfactants are additives to improve the incremental oil recovery provided by steam and miscible gas injection fluids. Improved and more cost-effective cross-linked polymer systems have resulted from a better understanding of chemical cross-links in polysaccharides and of the rheological behavior of cross-linked fluids. The thrust of completion and hydraulic fracturing chemical research has shifted somewhat from systems designed for ever deeper, hotter formations to chemicals, particularly polymers, that exhibit improved cost effectiveness at more moderate reservoir conditions. 

T0379 Hrubetz Environmental Services, Inc., HRUBOUT Process, In Situ T0380 Hrubetz Environmental Services, Inc., HRUBOUT Process, Ex Situ T0384 Hydraulic Fracturing—General... 

To optimize processes that are based upon the interaction between microstructure and flow (for example, proppant placement in hydraulic fracture of geologic formations [oil recovery], separations processes for biological materials, mixing and dispersion of additives in blenders, crystal growth and solidification processes). 

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