Larisa Masalimova 1, Donald Lowe 1 and Richard Derksen 2. (1) Stanford University, CA, USA (2) RAG, Austria

Transcription

1 Larisa Masalimova 1, Donald Lowe 1 and Richard Derksen 2 (1) Stanford University, CA, USA (2) RAG, Austria

2 About The Presenter 2008, B.Sc. in Geology and Exploration of Oil and Gas fields, RPFU, Moscow Thesis: Geology, Estimation of Reserves and Secondary Development of the Ayoganskoe Oilfield, Siberia to date, Ph.D. candidate in Geology, Stanford University Projects: 1. Submarine channel-lobe complex, Late Miocene Mount Messenger formation, New Zealand; 2. Overbank deposits, the Upper Austrian Molasse Basin; 3. Slurry beds of the Ouachita Basin, Arkansas and the San Joaquin Basin, California. Experience: Occidental Petroleum (OXY) with California Exploration (2010) and Elk Hills (2009) in Bakersfield, CA; Geophysical Expedition in Moscow (2008); TNK-BP in Nizhnevartovsk, Siberia (2007).

3 Background 3-5 km wide and 100 km long channel belt Oligocene to Early Miocene deposits (2000 m) Deposits: Conglomerates, sandstone and mudstone Accumulated within Ma (Martini, 1971) Channel belt flows to the east Flow 25 modified Zweigel et al.,1998; Hubbard et al.,2009 modified from De Ruig and Hubbard, 2006; Bernhdart, 2011

4 Background foreland basin Area of study deepens towards the active Alpine thrust front to the south and shallows to the north overbank and crevasse-splay sediments deposited by flows that spilled out of the main axial channel 25 modified Zweigel et al.,1998; Hubbard et al.,2009

5 Research objectives 1. Depositional mechanisms & environment of sediment accumulation in the studied fields How the lobes were deposited? Over spilling vs. breaching of the levee 2. Architecture of overbank deposits basin or channel-belt configuration influence on distribution of over-bank deposits 3. Spatial variation and lithological heterogeneity of out-of-channel deposits Predict the sandstone in the overbank area of the Molasse Basin

6 Lithofacies Thick-bedded sandstone. Beds are >50 cm thick and are >80% sandstone. Laminated mudstone with <20% sandstone With pebbles & mud clasts Massive and Bouma divisions

7 Lithofacies Thin-bedded sandstone & mudstone Slurry-beds, slumps, and debris flows Sandstone beds 5-50 cm thick, >20% sandstone sandstone beds <5 cm, >20% sandstone

8 Core: A A-40

9 Core: S S- 4 RAG courtesy

10 Quantitative analysis Time 1 Time 2 (modified from Droser & Botjjer, 1989) 87% 0% Average sand 57% Average Mud 43% Average Bioturbation 7% meters B 44, K % Sand Bioturbation

11 Quantitative analysis meters A 40, K1 Average sand 14.6% Average Mud 85% Average Bioturbation 9% A 40, K m m Average sand 23% Average Mud 76.5% Average Bioturbation 12.8% Sand Sand Bioturbation Bioturbation % meters % A20,K1 A20,K2 Time 1 Time 2

12 Completion logs and 3-D seismic Base of Hall Formation A-40 Z-12 A-40 Z-12

13 Seismic interpretation 8 horizons ms between horizons RMS amplitudes extracted from each horizon and between horizons Exploration interest A1-2 A3 A4 L. Puch

14 Seismic interpretation A1- Base of Hall Fm 2.5 km N A) 40 60m lower A3; B) lower A2 C) A1 interval (Hubbard et al., 2009) Background Research objectives Core and well logs Seismic Interpretations Conclusions

15 Seismic interpretation A4 interval N 2.5 km 1??? 2 1 2

16 interpretation Three hypotheses: 1) Flows from the channel crevasse splays 2) Flows into the channel tributary channels 3) Slumps remnants: originated from the sides of the channel, slumps were carried away by the flow in the channel and the space was filled with subsequent flows 2.5 km

17 Seismic interpretation Overbank deposition of the Upper Puchkirchen Formation can be subdivided into 3 steps from older to younger deposits: (1) deposition of multiple interfingering splays associated with erosional features directed perpendicular to the channel, (2) deposition of a single large splay on the north side of the channel, (3) development of a number of channels across the previous splay surfaces. 1 Base of the Upper Puchkirchen Fm Middle of the Upper Puchkirchen Fm 2 3 Top of the Upper Puchkirchen Fm

18 Conclusions 1. 4 lithofacies represent the core in the Puchkirchen Formation of the studied gas fields: Thin beds of sandstone & mudstone is the most common. 2. Low-density turbidity currents - sediment deposition far from the channel setting, high-density turbidity currents deposits - close to channel. 3. Slurry flows, debris flows & conglomerates is a sign of erosion (crevasse splay?) 4. Bioturbation intensity increases (?) and sand amount decreases with distance from channel. 5. Overbank deposits appear at the outer bank to the north of the channel. 6. The evolution of overbank deposits follow 3 stages: (1) deposition of multiple interfingering splays associated with erosional features (?) directed perpendicular to the channel, (2) deposition of a single large splay on the north side of the channel, (3) development of a number of channels across the previous splay surfaces.

19 Acknowledgement RAG personnel: Katarina Borowski, Nicola Kofler, Wolfgang Mitterlehner, Ulrich Bieg, Ralph Hinsch, Wolfgang Nachtmann, Olga Wronska, Wilma Troiss, Réka Kovách SPODDS Students: Blair Burgreen, Julie Fosdick, Katie Maier, Matt Malkowski, Nora Nieminski, Jon Rotzien Theresa Schwartz, Lauren Shumaker, Danielle Zentner Dominic Armitage Anne Bernhardt Zane Jobe Lisa Stright

20 Thank you for your attention! QUESTIONS?

21 Seismic interpretation A1-Hall Base 2.5 km N A) 40 60m lower A3; B) lower A2 C) A1 interval (Hubbard et al., 2009)