Abstract: Understanding Producibility in Turbidite Reservoirs: Improving on the Utility of Analog Studies

Thomas M. Byrd, Stephen P.J. Cossey

Traditional analog studies have focused on geologic similarities but neglected engineering differences vital to understanding producibility. Often, these qualitative comparisons are likened to comparisons of apples to oranges.

In an effort to constrain the risk of producibility in prospect ranking, appraisal and development planning, 140 well completions from fifty North Sea and Gulf of Mexico turbidite reservoirs were studied to understand geologic controls on plateau rates and well spacing. Plateau rates from individual reservoir completions were normalized for differences in viscosity, drawdowns, skins and thicknesses to permit better comparisons. Normalized producibility indices suggest the strong influence of solution gas/oil ratio, facies and reservoir architecture on production. For example, amalgamated sheet sand architectures exhibit very good production characteristics, but actual production may be predominantly influenced by completion designs. Major differences between consolidated vs. unconsoli ated reservoirs are attributed to differences in skins. While interpretation of facies and reservoir architecture remains qualitative, normalized comparisons permit better quantitative predictions of producibility and optimum well spacing in different reservoir architectures.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994