Effect of confining stress and fluid properties on arch stability in unconsolidated sands
A cylindrical sand pack, 52.75 in. long x 16 in. in diameter, was used to study the stability of unconsolidated sands across casing perforations. Bottom-hole producing conditions were approximated with overburden stresses of 250, 750, 1500, 2250, and 3000 psig. Fluid saturations consisted of an irreducible water phase and liquid hydrocarbons. The sand used was gopher state 20/40 frac sand, and the different hydrocarbon fluids investigated were kerosine and mineral spirits. The observed mechanism of sand stabilization around a well bore was the formation of sand arches across a perforation opening; an observation consistent with those of earlier investigations. Hence, sand instability was recorded at the moment of failure of sand arches. Arch structure is a function of the stress distribution in a sand pack. Maximum arch size and stability were also found to be a function of confining stress. The effect of different hydrocarbons on arch stability manifests itself in the cohesive forces in the pendular saturation of the wetting phase at the arch wall.
- OSTI ID:
- 5693767
- Report Number(s):
- CONF-790913-
- Journal Information:
- Soc. Pet. Eng. AIME, Pap.; (United States), Journal Name: Soc. Pet. Eng. AIME, Pap.; (United States) Vol. SPE-8426; ISSN SEAPA
- Country of Publication:
- United States
- Language:
- English
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