Reservoir Prediction and Development Challenges in Turbidite Slope Channels

Abstract

The paper discusses the challenges facing development of deepwater reservoirs deposited in turbidite slope channels. Consideration of the reservoir facies and stacking patterns shows the pitfalls and also the potential for mitigating the effect of flow barriers and baffles within reservoirs. This can impact many aspects of the development including reservoir modeling, well designs and development concept selection.Large Erosional Turbidite Channels are dominated by 4 major facies; Basal lags (good but generally thin reservoirs), slump and debris flows (poor or non-reservoir), high N:G sandy channels (good reservoir), and sinuous channel levees (thin sands difficult to develop). The development of these components and their stacking pattern can be recognized on seismic but there are significant pitfalls. Considering the detailed geometry of the reservoir facies may be important when assessing how easily wells from a fixed platform versus a subsea development can access the reservoir.Low-Relief Channel Levees comprise both sand and mudfilled axis with sandy levees. The muddy axis, heterogeneities in the levees and vertical stacking of channels give rise to development challenges which may require a compromise between the numbers of wells required to mitigate flow barriers and the risk of utilizing complex multiple completion or multilateral wells to minimize well numbers.The high expense of developments in deep water requires a thorough assessment of the subsurface risks. Understanding the potential pitfalls and having appropriate mitigation plans is critical to a successful economic development.

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

“…4). (Beydoun et al, 2002;Deptuck et al, 2003;Fonnesu et al, 2003;Kolla et al, 2001;Mayall and O'Byrne, 2002;Mayall and Stewart, 2000;Navarre et al, 2002;Posamentier et al, 2000;Sikkema and Wojcik, 2000;Wonham et al, 2000). The sinuosity varies from occasional bends in the channel to highly sinuous channels with numerous cut-off bends.…”

“…Recognising the stacking patterns within the channels is also critical in designing the location and orientation of development wells (Mayall and O'Byrne, 2002). As discussed earlier, there is a risk that the facies at the base of a channel may act as permeability barriers or baffles.…”

“…Critically this can potentially impact consideration of a development concept (Mayall and O'Byrne, 2002) (Fig. 22).…”

“…Turbidite channels are recognised as very important hydrocarbon reservoir types in almost all areas and settings where deep-water facies are being explored, appraised or produced (Beydoun et al, 2002;Brami et al, 2000;Broucke et al, 2004;Clemenceau et al, 2000;Deptuck et al, 2003;Fonnesu, 2003;Fugitt et al, 2000;Humphreys et al, 1999;Kendrick, 2000;Kolla et al, 2001;Mayall and O'Byrne, 2002;Mayall and Stewart, 2000;Navarre et al, 2002;Posamentier, 2003;Posamentier and Kolla, 2003;Posamentier et al, 2000;Prather, 2003;Prather et al, 1998;Sikkema and Wojcik, 2000;Wonham et al, 2000;Weimer and Slatt, 2004). Over the last 5-10 years, in particular, the significance of turbidite channel reservoirs to the hydrocarbon industry has substantially driven forward our understanding of these depositional systems.…”

Reconstruction of turbidity currents in Amazon Channel

“…Abreu, Sullivan, Pirmez, & Mohrig, 2003;Demyttenaere et al, 2000;Deptuck, Steffens, Barton, & Pirmez, 2003;Kolla, Bourges, Urruty, & Safa, 2001;Pirmez, Beaubouef, Friedmann, & Mohrig, 2000;Posamentier & Kolla, 2002, Posamentier, Meizarwin, Wisman & Plawman 2000. The impact of such understanding is potentially enormous given the costs and complexity of developing hydrocarbon resources trapped in submarine channel fills and associated deposits (Mayall & O'Byrne, 2002). While our qualitative understanding of the morphology and stratigraphy of these sinuous submarine channels has increased dramatically since the first observations of submarine channels in the deep ocean (Damuth et al, 1983;Menard, 1955;Shepard, 1966), the same cannot be said about the quantification of the erosion and deposition processes in sinuous submarine channels.…”