Sand Body Characterisation in Tidal Marine

Settings – Examples from the Malay Basin

Dr. M. Johansson

mjohansson@geode-energy.com

MODERN DAY DELTAS

Sundarbans, Bangladesh

Volga River Delta, Caspian Sea

Rajang River Delta, Sarawak

SCHEMATIC MAP OF TIDE DOMINATED DELTA

From Dalrymple & Choi 2007 (Earth Science Reviews 81 135-175)

SUNDA SHELF

Lower Glacial Maximum 21K BP

Mesozoic Sundaland

Depositional Environment

Journal of Sedimentary Research, 2017, v. 87, 17–40Research ArticleDOI: http://dx.doi.org/10.2110/jsr.2016.88

TIDAL SHOAL CORE

MS & MF-:Microfractures; SC-Synaeresis Cracks:SR- Shear Rotation; RS-Reactivation Surfaces;

Gy- Gyrolithes burrow; J-J shaped burrows; MC-mud filled cracks; Rp-Ripple Structures; Scl-clay

lam Sst; Sba-bioturbated Sst; Pa – Paleophycus burrows; Sl- lam Sst

FACIES CLASSIFICATION SCHEME

Core Description Facies Facies Described from the Image

Core Facies Image FaciesPetrophysical

Facies

Rock Type PHIT BFV T2LM KTIM Frequency Facies Code Facies Description Core Photo

1 0.26 0.04 376.22 1361.39 0.08

Sb Bioturbated Sandstone

2 0.25 0.04 105.07 937.01 0.07 Sltb Bioturbated Silty Sandstone

SlHorizontally Laminated

Sandstone

3 0.23 0.07 64.42 175.75 0.11

SrxRipple Cross-Laminated

sandstone

Scl Clay Laminated Sandstone

4 0.21 0.10 27.57 19.19 0.14SG

Glaugonite Calcite Cemented

Sandstone

5 0.21 0.12 21.90 15.36 0.20 Ssltb Bioturbated Silty Sandstone

SltrxRipple Cross-Laminated

Silty Sandstone

SrxrtSandstone Ripple Cross-

laminated with Rootlets

DmpDolomite horizon with Small

Pisoids

Msb Sandy Biouturbated Shale

Msl Sandy Laminated Shale

6 0.14 0.13 4.02 0.05 0.39 Mslt Silty-Shale (Mslt)

Msltb Silty Bioturbated Shale

Msrt Mudstone with Rootlets

RL Regressive Lag Deposit

Grain-size Analysis from CMR

Cross-Bedded SandstoneSsx

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

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clay vfslt fslt mslt cslt vfsd fsd msd csd vcsdgrvl

Way up

PETROPHYSICAL FACIES

CROSS-SECTIONAL

DISTRIBUTION

Journal of Sedimentary Research, 2017, v. 87, 17–40Research ArticleDOI: http://dx.doi.org/10.2110/jsr.2016.88

R.W. Dalrymple, K. Choi / Earth-Science Reviews 81 (2007) 135–174

VERTICAL DISTRIBUTION

DISTRIBUTARY CHANNEL

CHARACTERISTIC FEATURES OF DISTRIBUTARY

CHANNELS•Fining-up Grain-size

•High-angle cross-bedding

•Dominance of clean sand

•Paleosols evident with rootlets

•Abundance of calcite cement layers

Average Sand Body Average Thickness 25m thick

TIDAL CHANNELS

CHARACTERISTIC FEATURES OF TIDAL CHANNELS

•Coarsening-up grain size

•Cross-bedding (Hummocky Cross-Stratification)

•Dominance of Heterolithic facies or clay drapes

•Fine –medium grain sand

•Calcite Cements

Average Sand Body Average Thickness 3m thick

DISTRIBUTARY CHANNEL

CHARACTERISTIC FEATURES OF MOUTH BARS•Coarsening-up Grain-size

•Low-angle cross-bedding (Ripples)

•Dominance of Clean sand

•Rootlets at top of sand

•Little to no Calcite Cement

Average Sand Body Average Thickness 15m thick

FACIES TRANSITION

Mouth bar

Tidal Channel

Estuarine Channel

Controls on Sinuosity

- slope gradient

- bed resistance

- Sediment supply

- Flow RegimeSundarbans, Bangladesh

2km

2km 2km

HORIZONTAL DISTRIBUTION

TYPES OF SINUOSITY AND CHANNEL

WIDTH

2km

2km 2km

SIGNIFICANCE OF RESISTANCE ON

SINUOSITY

Generic theory for channel sinuosity Eli D. Lazarus and José Antonio Constantinehttps://doi.org/10.1073/pnas.1214074110

Resistance-dominated surfaces produce

channels with higher sinuosity than those of

slope-dominated surfaces because increased

resistance impedes downslope flow.

Straightened river after vegetation

cover is removed

https://doi.org/10.1073/pnas.1214074110

TYPES OF SINUOSITY

AND SAND/MUD RATIO

2km

2km

CONCLUSION

• Understanding the tidal marine-estuarine processes is critical to

understanding the nature of sandstone processes

•The relationship between sinuosity and facies, could provide a useful

exploratory tool

•Distinct sand bodies and palaeocurrents can be identified and placed in an

estuarine Geological model

•The combination of core, image logs, elemental spectroscopy and NMR

identified robust depofacies, lithofacies and rock types simplify complex

Any Questions?