Outcrop-Behind Outcrop Characterization of Thin-bedded Turbidites for Improved Understanding of Analog Reservoirs: New Zealand and Gulf of Mexico

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWell log, well test, and seismic data provide excellent structural and stratigraphic information on subsurface reservoirs, but may not be able to resolve small-scale vertical and lateral attributes which may control oil or gas production. Outcrops can provide this important information provided they are of sufficient areal extent. In this paper, we demonstrate the application of outcrop and behind-outcrop characterization for improved understanding of thin-bedded turbidite reservoirs in the Gulf of Mexico and elsewhere.A 200m high by 10km long coastal cliff section of the Late Miocene Mt. Messenger Formation, New Zealand consists of 200+ meters of thick-bedded turbidite fan sands and associated thin-bedded fan-fringe sandstone/siltstone, overlain by 300m of thin-bedded slope fan, levee/overbank sandstone/siltstone. This section was characterized at the 'seismic' to individual bed scales. Also, 47 and 105m deep holes were drilled behind the cliff face, cored, and logged through the slope fan facies with Fullbore Formation Micro Imager* and Platform Express* logs. A slope-fan model is presented which differentiates proximal levee facies composed mainly of discontinuous, erosionally-truncated Bouma Tb-c beds from * TM Schlumberger Wireline and Testing Co. Why Outcrop Characterization for Reservoir Studies??Discipline-integration within the petroleum industry during the past 10 years has changed the way in which geoscientists interact with reservoir engineers. Geoscientists have been forced from providing reservoir engineers with conceptual SPE 49563

Grain‐size characteristics for distinguishing basin floor fan and slope fan depositional settings: Outcrop and subsurface examples from the late Miocene Mount Messenger Formation, New Zealand

“…Mud-lined channels at various scales up to several tens of metres deep are common and have a major influence on lateral continuity of beds. Slope fan lithofacies represent channel-fill and levee environments on base-of-slope fans (King et al 1994;Slatt et al 1998;Browne et al 2000;Browne & Slatt 2002).…”

“…In such depositional settings, well spacing can be greater, as individual wells can efficiently sweep a relatively large reservoir area. Slope fan units, however, show less extensive lateral development with typically channel and levee elements, which display considerable erosion of lithofacies and a lesser degree of reservoir sandstone communication (Browne & Slatt 1997;Slatt et al 1998;Browne et al 2000). In slope fan settings, exploration wells need to be relatively closely spaced to avoid lateral variations in sand thickness and communication.…”