LLL Gas Stimulation Program. Quarterly progress report, July--September 1978
The research and accomplishments of the LLL Gas Stimulation program during the fourth quarter of Fiscal Year 1978 is summarized. Two-dimensional theoretical models were applied to analyze the changes in the elastic stress field resulting from the presence of lenses in a surrounding medium. Here the lenses had different elastic moduli than the surrounding medium, and the emplaced load was assumed to be caused by the overburden. In these calculations, it is noted that the growth of a vertical fracture toward a lens with elastic moduli larger than the surrounding medium would be impeded. Other two-dimensional calculations indicate some effects of material parameter changes across an interface on fracture mechanics. These calculations confirm that when a fracture in a lower modulus material aproaches a well-bonded interface in a higher modulus material, the stress intensity factor decreases. Experimental results show that water saturation can significantly effect hydraulic fracture propagation. An example is a hydraulic fracture across a normally loaded interface from an unsaturated limestone block into a saturated block but not conversely for the same hydraulic pressure and normal load. Some preliminary experiments were conducted to determine how rock behaves when subjected to loads at rates higher than hydraulic fracturing but lower than explosive charges. Results indicate more than the two fracture wings common to normal hydraulic fracturing. A survey of several operators and logging companies operating in the western tight gas sands shows that log measurements do not define pertinent reservoir parameters accurately enough to exploit these reservoirs.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6567828
- Report Number(s):
- UCRL-50036-78-3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HYDRAULIC FRACTURING
RESEARCH PROGRAMS
NATURAL GAS WELLS
WELL COMPLETION
WELL STIMULATION
ROCKS
CALCULATION METHODS
GEOLOGIC STRUCTURES
GREEN RIVER FORMATION
PRESSURE DEPENDENCE
STRESSES
TWO-DIMENSIONAL CALCULATIONS
COMMINUTION
FRACTURING
WELLS
030300* - Natural Gas- Drilling
Production
& Processing