Turbidite channel reservoirs - Key elements in facies prediction and effective development

Turbidite channels are important but frequently complex reservoirs in the exploration, appraisal and development of deep-water facies. Over the last 10 years in particular, high-resolution seismic data and extensive outcrop studies have increased our knowledge of the complexity of these sedimentary bodies. Such is their variability and complexity that developing and applying single or even multiple depositional models has limited applicability. Instead, we recognise an alternative approach to help rapidly evaluate turbidite channel reservoirs. The paper mainly concerns the evaluation of large erosionally confined 3rd-order channels, typically 1-3 km wide and 50-200 m thick. Each channel is unique but each generally has four recurring elements namely, the sinuosity, the facies, repeated cutting and filling and the stacking patterns. Several different styles of sinuosity can be identified, each having different implications for sand distribution. Four main facies can often be recognised on seismic, calibrated by cores and logs; a basal lag, slump/debris flows, high net:gross stacked channels and low N:G channel levees. Most channels contain all of these facies but in widely varying proportions. Repeated cutting and filling is a feature of just about every channel studied. The process has major implications for reservoir and non-reservoir distribution. The stacking patterns of the 4/5th-order channels within the 3rd-order channel can have a critical impact on facies and heterogeneity distribution and can strongly influence well design and even potentially the development concept. This paper discusses the impact of each of these elements on exploration, appraisal and development issues. (c) 2006 Elsevier Ltd. All rights reserved.