Marine Depositional Environments Basics Marine Shelf and Deepwater. (Last Updated 28 December 2015) COPYRIGHT

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1 Marine Depositional Environments Basics (Last Updated 28 December 2015)

2 NOTICE AND DISCLAIMER The information contained herein and/or these workshop/seminar proceedings (WORK) was prepared by or contributed to by various parties in support of professional continuing education. For purposes of this Disclaimer, Company Group is defined as PetroSkills, LLC.; OGCI Training, Inc.; John M. Campbell and Company; its and their parent, subsidiaries and affiliated companies; and, its and their co-lessees, partners, joint ventures, co-owners, shareholders, agents, officers, directors, employees, representatives, instructors, and contractors. Company Group takes no position as to whether any method, apparatus or product mentioned herein is or will be covered by a patent or other intellectual property. Furthermore, the information contained herein does not grant the right, by implication or otherwise, to manufacture, sell, offer for sale or use any method, apparatus or product covered by a patent or other intellectual property right; nor does it insure anyone against liability for infringement of same. Except as stated herein, COMPANY GROUP MAKES NO WARRANTIES, EXPRESS, IMPLIED, OR STATUTORY, WITH RESPECT TO THE WORK, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Company Group does not guarantee results. All interpretations using the WORK, and all recommendations based upon such interpretations, are opinion based on inferences from measurements and empirical relationships, and on assumptions, which inferences and assumptions are not infallible, and with respect to which competent specialists may differ. In addition, such interpretations, recommendations and descriptions may involve the opinion and judgment of the USER. USER has full responsibility for all interpretations, recommendations and descriptions utilizing the WORK. Company Group cannot and does not warrant the accuracy, correctness or completeness of any interpretation, recommendation or description. Under no circumstances should any interpretation, recommendation or description be relied upon as the basis for any drilling, completion, well treatment, production or other financial decision, or any procedure involving any risk to the safety of any drilling venture, drilling rig or its crew or any other individual. USER has full responsibility for all such decisions concerning other procedures relating to the drilling or production operations. Except as expressly otherwise stated herein, USER agrees that COMPANY GROUP SHALL HAVE NO LIABILITY TO USER OR TO ANY THIRD PARTY FOR ANY ORDINARY, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSSES WHICH MIGHT ARISE DIRECTLY OR INDIRECTLY BY REASON OF USER S USE OF WORK. USER shall protect, indemnify, hold harmless and defend Company Group of and from any loss, cost, damage, or expense, including attorneys fees, arising from any claim asserted against Company Group that is in any way associated with the matters set forth in this Disclaimer. The Content may not be reproduced, distributed, sold, licensed, used to create derivative works, performed, displayed, transmitted, broadcast or otherwise exploited without the prior written content of the Company Group. Use of the WORK as a reference or manual for adult training programs is specifically reserved for PetroSkills, LLC. All rights to the WORK, including translation rights, are reserved. PETROSKILLS, LLC., 2015 THIS WORK IS ED BY PETROSKILLS, LLC. AND DISTRIBUTED UNDER EXCLUSIVE LICENSE BY PETROSKILLS, LLC.

3 DELIVERING KNOWLEDGE. DEVELOPING COMPETENCE. Marine Depositional Environments Basics Marine Depositional Environments 2 1

4 Depositional Environments Processes and examples from modern and ancient environments with oil field examples Subaerial Alluvial fan Fluvial braided and meandering Aeolian wind and desert Marginal marine Delta river, wave, tide dominated, fan delta, braid delta Beach and barrier island Marine Offshore Bars Submarine fan channel-levee complex, Bouma sequence Carbonates limestone, dolomite Reef, platform, pinnacle, pelagic Diagenesis Objectives of the Offshore Bar Session You will learn: About how offshore bars form Morphology Sediments About the distribution of sediments on a bar How to recognize in outcrop and on well logs 3 4 2

5 Distribution of Surficial Sediments Louisiana Continental Shelf Distribution of surficial sediments on the Louisiana continental shelf (after Frazier, 1974). Shoal and shelf sand bodies related to transgression of abandoned complexes of the Mississippi delta, and shelf sands to the SW resulted from transgression of Pleistocene shoreline and coastal plain deposits during Holocene sea level rise (Suter 1987, 2006). 5 Generation of Marine Bodies by Fluctuations in Sea Level Generation of marine bodies by fluctuations in sea level (From Walker and Plint, 1992). (a) Wave-dominated shorelines form as part of an HST, fall in base level (forced regression) forms as series of shoreface deposits, resulting in falling stage and lowstand profiles. A prograding shoreface is established at lowstand (SL VII); (b) rising sea level submerges the coastal plain, the ravinement surface is caused by shoreface erosion. Given sufficient sediment supply, shelfal muds will bury earlier sands. 6 3

6 Generation of Marine Bodies by Fluctuations in Sea Level 7 Generation of Marine Bodies by Fluctuations in Sea Level 8 4

7 Major Physical Processes Influencing Sediment Transport and Deposition Block diagram illustrating the major physical processes influencing sediment transport and deposition on clastic shelves (Suter 2006 after Nittrouer and Wright, 1994). 9 Qualitative Process Classification of Continental Shelves Qualitative process classification of continental shelves (Johnson and Baldwin, 1996) 10 5

8 Schematic Diagram for Postulated Development of New Jersey Shelf Ridges Schematic diagram for postulated development of New Jersey shelf ridges (from Nummedal and Suter 2002) Offshore Bar underlain and overlain by Marine Shales. Note people on outcrop for scale. Outcrop Example From Jurassic / Cretaceous Offshore Bar Outcrop

9 Outcrop Example From Jurassic / Cretaceous Vertical Section Marine Bar (Outcrop) Outcrop Example From Jurassic / Cretaceous Base of Offshore Bar

10 Outcrop Example From Jurassic / Cretaceous Burrows Near Bar Base Outcrop Example From Jurassic / Cretaceous Ripple Cross Lamination, Middle Portion of Offshore Bar

11 Outcrop Example From Jurassic / Cretaceous Cross Stratification, Offshore Bar Top Outcrop Example From Jurassic / Cretaceous Alternating Deposits From Storm and Fair Weather Conditions (Part of the bar sequence)

12 Outcrop Example From Jurassic / Cretaceous Coquinoid Sandstone: Storm Deposit Objectives of the Offshore Bar Session You have learned: About how offshore bars form Morphology Sediments About the distribution of sediments on a bar How to recognize in outcrop and on well logs

13 Depositional Environments Processes and examples from modern and ancient environments with oil field examples Subaerial Alluvial fan Fluvial braided and meandering Aeolian wind and desert Marginal marine Delta river, wave, tide dominated, fan delta, braid delta Beach and barrier island Marine Offshore Bars Submarine fan channel-levee complex, Bouma sequence Carbonates limestone, dolomite Reef, platform, pinnacle, pelagic Diagenesis Objectives of the Submarine Fan Session You will learn about: Channel-levee complexes Morphology Sediments The distribution of sediments on a fan Turbidity currents, turbidites, and the Bouma sequence Exploration potential

14 Submarine Fans Off California Coast Submarine fans off California coast accumulate at base of continental slope, similar around the world. Fans coalesce similar to alluvial fans. Each is fed by its own channel system. Recall The Beach a River of Sand video. Recall sand cascading down the canyon. 23 Diagrammatic of a Submarine Canyon / Fans Complex 24 12

15 Depositional Lobes on a Fan 25 Sediment Types in the Channel / Fan Complex 26 13

16 Relationship Between Channel, Levee, and Overbank Deposits 27 Slopes of Different Areas of the Bengal Fan Lower Fan <1/10th of 1% Grade Upper Fan... <10% Grade 28 14

17 Indus Fan Note Size of Indus Fan Approx km in width and 1800 km in length. Areal dimensions controlled by topographic ridges related to Plate Tectonics khz Echogram of a Portion of the Indus Fan Indus Fan: Levees more fine grained than in a delta / meandering fluvial system. Channel incision is 300m deep / levees 500m high And channel is 30 km wide 30 15

18 Indus Fan Depositional Model 31 Indus Fan: Looks Like a Meandering Fluvial System 32 16

19 Amazon Fan / Cone 33 Channel and Levee Complexes, Amazon Fan 34 17

20 Geomorphology of Channel and Levee Complexes, Amazon Fan Note locations of sub-bottom profiles A, B and C on next slide 35 Sub-bottom Profiles of Channel and Levee Complexes Amazon Fan 36 18

21 Surface vs. Subsurface Evidence of Submarine Channels Side scan sonar of Indus Fan on left Enhanced seismic of a submarine channel fill, Nile Fan, offshore Egypt 37 3 Short Videos of Turbid Flow and How Turbidites Form 38 19

22 1929 Grand Banks Cable Breaks Evidence for Turbid Flow 1929 Grand Banks Canada Breaking Telephone cables. Earthquake of magnitude 7.2 triggers Turbid Flow of Shelf and Slope sediments. Time lapse: 4:30pm start, 7pm at mid, 5am at distal 60+mph at proximal (500 km cables) (1700+km flow) (1000miles) 25 mph at distal ~200 cu kms (~50cu mi) sediment: 29 killed (tsunami-4m high waves x3 times hit coast at 65mph) 39 Turbid Flow Can Result in Bouma Sequences Arnold H. Bouma ( ), a Dutch Geologist, was the first to describe a classic set of sedimentary structures in Turbidite Beds deposited by Turbidity Currents. Compare to point bar Small ripples Parallel beds Large ripples. Pebbles/coarse sand can be massive or graded. When next flow comes, can erode some or all of previous one

23 Turbid Flow Can Result in Bouma Sequences 41 Full and Partial Bouma Sequences in Outcrop Bouma A sequence SE of France, North of Nice 42 21

24 Full and Partial Bouma Sequences in Outcrop Characteristic Bouma C sequence above Howard Dewhirst s head Bouma B at his shoulder Northern Italy 43 Full and Partial Bouma Sequences in Outcrop Bouma A cutting into Bouma C Note potential impact on reservoir quality North Italy 44 22

25 Full and Partial Bouma Sequences in Outcrop Note Erosional bases of Bouma A sequences 45 Full and Partial Bouma Sequences in Outcrop 46 23

26 Full and Partial Bouma Sequences in Outcrop Conglomerates and sandstones in feeder channel 1km wide. Cgl is fist size (see next slide). Cgls are up to 2m thick and 30-40m wide. Individual units did not occupy entire channel, just parts. Transport was out of the pic towards viewer. 47 Feeder Channel Deposits Dana Point, Southern California 48 24

27 Close-up of Feeder Channel Deposits Dana Point, Southern California Close up of cgl and very coarse-grained ss channel fill. Yellow book fits in your back pocket. Which looks like better reservoir rock? Could you differentiate the 2 sand bodies on logs? 49 Near Vertical Edge of Feeder Channel Deposits Notice how the sandstone bodies weather differently indicating a slight change in lithology. Could we see difference on logs? 50 25

28 2 Different Feeder Channel Deposits One Atop the Other Notice how the sandstone bodies weather differently and have different vegetation indicating a slight change in lithology. Could we see difference on logs? Mid fan channel; 200 m thick and 2 km wide. Possible model for the 40 s Field, North Sea. (65 wells, shut in pressures same, production pressures disparate.) 700 m well spacing 51 Mid-Fan Channel Deposits Apennines of Italy 52 26

29 Mid-Fan Channel Deposits Apennines of Italy This picture to left of previous one. Note: Discontinuity between 2 different channel fills. Note permeability barriers causing fluids to come out of outcrop. This could lead to possible reservoir continuity effects. 53 Being Able to Image A Channel Base From High Resolution Logs Channel fill eroded into underlying sh at X139. Note change in dips from channel into underlying shale. Arrow is erosional contact 54 27

30 Lower (Outer) Submarine Fan Deposits Distal limits of fan channel surrounded by thin beds of lower fan 55 Distal Limits of a Fan Channel Sisar Creek, S. California near Santa Barbara 56 28

31 Distal Limits of a Fan Channel Similar to a Distributary mouth bar at the end of a channel-levee complex on lower fan. This is very distal. Finely laminated sands, silts and shales of outer/distal fan Most sands below resolution of conventional well logs. If logs average hydrocarbon productive thin beds with shales, logs would indicate a dry hole. Similar wells in GoM produce over 7,000 bopd 57 Distal Fan Facies 58 29

32 High Resolution Logs Can Differentiate Pay From Shale 59 Soft Sediment Deformation of Distal Fan Sediments What effect will this type of deformation have on reservoir Continuity? 60 30

33 Soft Sediment Deformation of Distal Fan Sediments Submarine fans are progradational and coarsen up overall. Channel fills, however, fine upward as the slope of a channel decreases as it fills from the bottom up 61 Examples of Petroleum Production From Submarine Channel / Fan Reservoirs 62 31

34 Seismic Line Over Main Pass Block 225 Discovery Can t see much on seismic, but can see the amplitude of the producing horizon come and go. 63 Subsurface Structure Map and Outline of Seismic Amplitude Note: long and narrow, shape of channel / fan complex. Resulted in drilling a horizontal well Also note that the amplitude does NOT conform to structure

35 Seismic Line Over Trajectory of Horizontal Well 65 Geologic Cross-Section Through 3 Producing Wellbores Notice resistivity through productive section in horizontal well. Although GR log looks homogeneous, resistivity varies crossing through multiple, potentially separate sand lobes? 66 33

36 Selected Deep Water Fields, GOM Through 1995 Lena Field, XOM 1000 ft water Pliocene aged reservoirs ( myo) General Reservoir Properties: 27% porosity md Net/Gross ~50% 67 Lena Field, Offshore Louisiana 68 34

37 Lena Stratigraphic Model Seismic Expression of Stratigraphic Model

38 Seismic Expression of Weakly Confined Channels 71 Seismic Example of Stacked Channels 72 36

39 Stratigraphic Cross Section Through Submarine Channel Sands No sands in communication vertically and only a few sands in communication laterally. Implications for completions, waterflooding, pressure maintenance, etc.? 73 North Sea Submarine Fan Complexes 74 37

40 Submarine Fan Complexes at the End of the Lower Eocene 75 Objectives of the Submarine Fan Session You have learned about: Channel-levee complexes Morphology Sediments The distribution of sediments on a fan Turbidity currents, turbidites, and the Bouma sequence Exploration potential 76 38