High-energy gas fracturing in cased and perforated wellbores

Technical Report · Sun Jun 01 04:00:00 EDT 1986

DOI:https://doi.org/10.2172/5715454· OSTI ID:5715454

Cuderman, J F

A propellant-based technology, High-Energy Gas Fracturing (HEGF), has been applied to fracturing through perforations in cased boreholes. HEGF is a tailored-pulse fracturing technique originally developed by Sandia National Laboratories for application in uncased, liquid-free gas wells in Appalachian Devonian shales. Because most oil and gas wells are liquid filled as well as cased and perforated, the potential impact of present research is significantly broader. A number of commercial tailored-pulse fracturing services, using a variety of explosives or propellants, are currently available. Present research provides valuable insight into phenomena that occur in those stimulations. The use of propellants that deflagrate or burn rather than detonate, as do high-order explosives, permits controlled buildup of pressure in the wellbore. The key to successful stimulation in cased and perforated wellbores is to control the pressure buildup of the combustion gases to maximize fracturing without destroying the casing. Eight experiments using cased and perforated wellbore were conducted in a tunnel complex at the Department of Energy's Nevada Test Site, which provides a realistic in situ stress environment (4 to 10 MPa (600 to 1500 psi)) and provides access for mineback to directly observe fracturing obtained. Primary variables in the experiments include propellant burn rate and amount of propellant used, presence or absence of liquid in the wellbore, in situ stress orientation, and perforation diameter, density, and phasing. In general, the presence of liquid in the borehole results in a much faster pressure risetime and a lower peak pressure for the same propellant charge. Fracture surfaces proceed outward along lines of perforations as determined by phasing, then gradually turn toward the hydraulic fracture direction. 8 refs., 23 figs., 3 tabs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5715454
• Report Number(s): SAND-86-1133; ON: DE86013068
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030900* -- Natural Gas-- Artificial Stimulation
Plowshare-- (-1989)
15 GEOTHERMAL ENERGY
58 GEOSCIENCES
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
BOREHOLES
CAVITIES
COMMINUTION
COMPARATIVE EVALUATIONS
DATA
EXPERIMENTAL DATA
EXPLOSIVE FRACTURING
FRACTURING
Geothermal Legacy
INFORMATION
NUMERICAL DATA
PERFORATION
PRESSURIZING
PROPELLANTS
TIME DEPENDENCE
TUFF
WELL CASINGS