1. Using the Oil Mud Reservoir Imager (OMRI) to create Bouma Litho-Facies Geomodeling Curve Data from Gulf of Mexico Turbidite Sediments.
Chris Williams, MS., PG.
Senior Geoscientist

2. The question of how to convert log response to rock type is an old one, in 1919 the first use of electrical measurements of rocks in a wellbore, was used to determine the suitability of a metal ore body, to be mined.
Old Schlumberger film from Leon Williams and we don’t know who made it (circa 1932). (

3. Hydrocarbon Column Interval
Detailed
Net Sand Count
Litho-Facies Reservoir Quality
Introduction
Net Sand Count
Sand Top
Sand thickness is important but the real question is, “How Much of the Sand is of Reservoir Quality?
In some deep water turbidite reservoirs, less than half of the potential hydrocarbon interval contributes to production.
This Litho-Facies Analysis approach is designed to qualify the sands in terms of reservoir quality.
110’
105’
97’
63’
Base

4. Introduction
Bouma, A., (1962)
Photo by C. Hans Nelson, (1978)

5. Turbidity Suspension Debris Flow Traction flow
Background
Turbidite flows use three main mechanisms to transport particles.
Debris flows
Traction flows
Suspension flows
Turbidity Suspension
Head
Debris Flow
Traction flow
Modified from Young K. Sohn (2000)

6. Classical Deepwater Turbidite Facies Architecture
Background
Turbidites deposits are the result of moving clastic sediments from up slope to down slope in a deep aqueous environment.
Classical Deepwater Turbidite Facies Architecture
Slope
Inner Fan
Middle Fan
Outer Fan
Confined Turbidite Deposits
Semi-Confined Turbidite Deposits
Un-Confined Turbidite Deposits
modified from Campion et al., 2005.

7. Confined Turbidite Setting (Inner Fan)
Background
Turbidites can be classified by the environmental settings in which they are deposited. Each setting is characterized by a depositional style.
Confined Turbidite Setting (Inner Fan)
Channel Lag Deposits
Debris Flow Deposits
Stacked Sand Filled Channels
Silty-Shaley Channel Matrix
Main Turbidite Channel Margin
modified from Campion et al., 2005.
Good sand quality but limited areal coverage.

8. Semi-Confined Turbidite Setting (Middle Fan)
Background
Sand Filled Channel Deposits
Semi-Confined Turbidite Setting (Middle Fan)
Main Turbidite Channel Margin
Silty-Muddy Channel Matrix
modified from Campion et al., 2005.
This setting makes for the most idea area for well placement, due to it being located nearest the best reservoir quality and connectivity to the downslope un-confined sections.

9. Background Un-Confined Turbidite Setting (Outer Fan)
modified from Campion et al., 2005.
Sandy, Sandy-Silty Turbidite Fan Lobes
Un-Confined Turbidite Setting (Outer Fan)
Turbidite Lobe Margins
Muddy Matrix
This setting has poorer sand quality but, can spread for 10’s of kilometers in all directions, creating huge fetch areas for hydrocarbons to migrate and collect.

10. Typical Turbidite Facies Association
Background
Typical Turbidite Facies Association
Facies F, which are remobilized chaotic blocks of laminated sands, silts and muds often associated with slumping. F E
Facies E, is almost entirely very thinly bedded clays and mudstone. D
Facies D, also heterolithic, are mostly silty nearer the base with higher mud content and less silt nearer the top. C
Facies C, are the first heterolithic beds deposited, laminated beds with soft sediment injection features grading to finer sediments higher in the column. B
Facies B, are the first deposited sediments with sorted features, often laminated beds grading thinner and finer upwardly with water escape features near the top. A
Facies A, are the basal debris flow deposits often described as chaotic.

11. Methodology, Step One
Is to identify the zones of interest to be analyzed.
Image logs are excellent for this. Oil Based Mud Resistivity Image (OMRI), X-Tended Range Micro Imager (XRMI) or, Circumferential Acoustic Scanning Tool (CAST) and gamma ray curve (GR) do a great job of defining bed boundaries.
Zone 1
Zone 2
Zone 3
In this slide 3 zones of interest have been identified.

12. Methodology, Step Two
Is integrating our knowledge of turbidite events, with all available data into an image log depth frame work.
Zone 1
Sandy and Muddy Heterolithic lithologies, generally response well to dipmeter picking. As does Bouma Facies C, D and E.
Zone 2
Zone 3

13. Integrating all available data.
Methodology, Step Two
Integrating all available data.
Note lithologies and grain sizes in available mud logs.
Note patterns of Increases or decreases grain size.
Dark green grey marine Shale, traces of Silt.
Shale
Silt and traces of very fine grain Sand.
Fining Upward Pattern
Very fine grain Sand, occasional fine grain Sand grading to very fine gain Sand.
Sand
Silt

14. Neutron Porosity 0.5 ft. Avg.
Methodology, Step Two
Integrating all available data (Wireline and LWD).
LWD Data
2MHz Resistivity Corrected
400kHz Resistivity Corrected
Gamma Ray 0.5 ft. Avg.
Delta T Compressional
Bulk Density 0.5 ft. Avg.
Neutron Porosity 0.5 ft. Avg.
Delta T Comp. Long
Zone 1
Zone 2
Zone 1
Zone 3
Zone 2
Look at the Log Curve data, relative to the surrounding rocks.
Zone 2 shows higher relative GR, lower Restivity, faster Delta T and higher Bulk Density than zones 1 or 3.

15. Methodology, Step Three
Is to compare Image log textural appearance against the zones log response and litho description.
Facies A, found in the confined and semi-confined “channelized” regions, when present appears at the base of turbidite events’ as a massive texture, with perhaps, ripped up clast from the surface below.
OMRI Image
XRMI Image
Facies B
Facies B
Facies A
Possible Rip-up clast
Facies A
Facies D
Facies D

16. Methodology, Step Three
From Rock Outcrop
Facies B
Methodology, Step Three
Facies B, Fine grain sand beds with likely soft sediment water escape structures near the top.
OMRI Image
XRMI Image
Likely soft sediment deformation features.
Facies B
Facies B
Facies D

17. Methodology, Step Three
Facies C, sandy heterolithic thinly laminated, very fine grain sands and silts with soft sediment water escape structures.
OMRI Image using CoreBox
Likely soft sediment deformation features.
From Rock Outcrop
Uniform dip throughout section
Facies C

18. Methodology, Step Three
Facies D, muddy heterolithic thinly laminated muds and ultra thin silty muds.
OMRI Image
Dipmeter plot
As bed thickness becomes thinner than the resolution of the tool to detect them, the beds can appear as massive and auto dip will not make dip picks.
XRMI Image
Facies D
From XRMI
Facies D

19. OMRI CoreBox View Methodology, Step Three XRMI Image
Facies F, are remobilized chaotic blocks of laminated sands, silts and muds often associated with slumping. This texture indicator is indicative of being in a confined turbidite channel setting. Additionally, the more numerous the slump features, the closer the well is likely to be near a channel margin.
XRMI Image
(Facies F) Slump block falling into (Facies D) Muddy heterolithic channel

20. Conclusions
Litho-Facies Analysis Data is a product we can deliver to clients.
Facies are customizable to the needs of the client.
In this example we added a C- and D+ Facies.

21. Conclusions
Pseudo Whole Core
Litho-Facies Analysis Data in “pseudo whole core” format.
Sand counts is now both qualitative and quantitative.
Geologist now have a new tool to aid in the construction of depositional models.
And Reservoir Engineers can more precisely simulate how a reservoir will react to production.

22. Thank you
Chris Williams, MS., PG.
Senior Geoscientist