Gas-cap effects in pressure-transient response of naturally fractured reservoirs

Ali Soud Al-Bemani, U. Sultan Qabous, Iraj Ershaghi

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This paper presents a theoretical framework of gas-cap effects in naturally fractured reservoirs. General pressure solutions are derived for both pseudosteady-state and unsteady-state matrix-fracture interporosity flow. Deviation from the fracture or fracture-matrix response occurs as the gas-cap effect is felt. Anomalous slope changes during the transition period depend entirely on the contrast between the fracture anisotropy parameter,λ1, and matrix-fracture interporosity parameter, λ, and between the total gas-cap storage capacitance (1 - ω1) and oil-zone matrix storage (1 - ω). A composite double-porosity response is observed for ω1 ≤ ω1c and 1.0 ≤ λ1/λ ≤ 1000. A triple-porosity response is observed for ω1 ≥ ω1c and 140 < ωλ1/λ < 1.0E05.

Original languageEnglish
Pages (from-to)40-45
Number of pages6
JournalSPE Formation Evaluation
Issue number1
Publication statusPublished - Mar 1997


ASJC Scopus subject areas

  • Process Chemistry and Technology

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