JOANA Practical 16 / 04 / 2010
Practical in Carbonate Sequence Stratigraphy The Joana Field (Paris Basin) Stratigraphic correlation between four cored wells (at a reservoir scale) Fabrice GAUMET (
[email protected])
Introduction to Paris Basin Petroleum context • Intracratonic basin - 110 000 km2 • Up to 3000 m of Mesozoic-Cenozoic
sediments • 290 million bbl produced from 50 fields (since 1950) ● Oil production (2006): 4.3 million bbl (583 kt) ● 109 producing wells, 47 injector wells ● 1 exploration well
Paris Basin: schematic geological cross-section
Geological context • Source rock: Liassic marine black shales • Oil generation: Late Cretaceous/Paleocene • Main reservoirs: – Triassic sandstones – Jurassic -Callovian- marine limestones • Traps are structural, of low amplitudes, or mixed structural-stratigraphic • 2 major difficulties: – calculation of static corrections (velocity anomalies exist in superficial chalk) – prediction of porosities in the Callovian
Three Petroleum Systems
After Espitalié, 1987
Jurassic Palaeogeography
Paris basin: the NW passive margin of the alpine basin
Basin-scale NW-SE cross-section
Isopachs of Dogger limestones
Upper Bathonian: a wide rimmed lagoon
Gaumet, 1997
Callovian: Lower Callovian: Isolated Shoals Mid-Up. Callovian: General drowning
Joana Field
RGE Course, 15 march 2005
Gaumet, 1997
Joana field
2 km
Oil impregnations: J3, J2D, J5D Oil shows: J4D, J6, J8D
Joana Oilfield structure map at top Lower Callovian 0 -1 1 5
N
-1 1 4 0
-1 1 3 0
-1 1 2 0
EM 2 -1 1 1 0
EM 1
-1 1 00
J9 J 9GD
-1 0 90
J3
J 5D J 2D J6
J 10D J 1D
-1 0 80
J7 J 4D
-1 0 7 0
J 7GD
-1 0 6 0
J 8D
-1 0 5 0
-1 0 4 0
-1 0 30
(Murat, 1992)
Seismic line Cluster
0
Oil Producer
Active Under observation
Water Producer
1
Active Shut
Injector
2 Km
Active Shut
AbandonedWell
Aim of the Practical • At a reservoir scale, propose a stratigraphic correlation between four cored wells (for the drilling of a new well) • Method : – Based on cores: • Recognition of sedimentary surfaces (Ex.1) & facies (Ex.2, 3) • Recognition of stratigraphic surfaces (time-lines) by the use of the facies model (« stacking pattern » of depositional environments (Ex.4)
– Based on cores/logs: • Core-log depth matching (Ex.4) • Sequence stratigraphy correlations (Ex.5)
SEQUENCE STRATIGRAPHY CORRELATIONS: A FIRST TRY WITHOUT CORE DATA
15 kms
3 kms
DATUM SELECTION
15 kms
3 kms
CORRELATION OF HARD MARKERS (MFS, SB, others...)
15 kms
3 kms
DIFFICULTIES IN WELL LOG CORRELATION: CARBONATE PLATFORM SETTINGS
15 kms
+ DIAGENESIS
3 kms
FIRST CORRELATION MODEL...
15 kms
3 kms
ALTERNATIVE MODEL : LATERAL FACIES CHANGE
15 kms
3 kms
CORE DATA GIVES AVAILABLE CONSTRAINTS (Facies, Biostratigraphy)
NEW CORRELATION MODEL BASED ON WELL LOGS and CORE DATA
NEW CORRELATION MODEL: BENEFITS?
15 kms
3 kms
15 kms
3 kms
Sedimentary Surfaces
Erosional surfaces
Hardground (HG) = Perforated Surface
Ex.1 - Sedimentary Surfaces on Cores A
B
C
D
Exercises 2 & 3 - Facies recognition Sedimentary facies = Lithological and paleontological characteristics which define a sedimentary rock, determined by depositional processes
slightly modified from Homewood et al., 2000
Of what is built a Carbonate Facies ? MATRIX
CEMENT
POROSITY
SKELETAL NON-SKELETAL
Different scales of Facies
Sedimentary "body" = Facies association
Facies Model
DISTAL
Exercise 2 – Core Macrofacies Distribution Along the Depositional Profile
Exercise 2 – Core Macrofacies distribution
Exercise 3 – Microfacies Distribution Along the Depositional Profile
Exercise 3 – Microfacies distribution
C
Stacking Pattern of Facies (/ Dep. Env.) records Depositional Sequences with their dedicated Surfaces (SB, MFS) MACROFACIES
Distribution of facies
Example of Sequence definition by vertical (time) « Facies » evolution (stacking pattern)
Sedimentary Surfaces & Facies
SB
Seq.2 MFS Surfaces For Correlations (Geological Model) SB Seq.1
Dataset: cores and thin-sections
Dataset: thin sections
7 - 1528,75m -
Exercise 4 – keys for Microfacies recognition
Exercise 4 – keys for Microfacies recognition
M
W
P
G
B
C
Based on Dunham's classification
+ dominant elements
Non-Skeletal o = oolithes/ooids p = pelloids onc = oncoids l = lithoclasts
Packstone, oncoid-rich
= Wab, Ponc
Skeletal b = bioclasts e = echinoderms br = bryozoans biv = bivalves
Wackstone, argillaceous & bioclast-rich
+ grain-size (fg, cg, vcg, etc...) + sorting (well, moderate, bad...)
Exercise 4 – keys for Microfacies Description
http://www.ulg.ac.be/geolsed/TP/
http://www.eos.ubc.ca/courses/eosc221/sed/sili/
Exercise 4 – keys for Microfacies Description Frequency chart
Spherical, Rounded
Angular Sorting Chart
J2D – 1D Sequence definition – Exercise 4 MDcore = MDlog +/-
m?
Exercise 5: 2D Correlation
J2D Interpretation
Core/Log depth matching
Exercise 5: 2D Correlation
Core / log depth matching, datum
Datum selection
From W to E: 2 km
Correlation Framework
Delineation of reservoir units
C4A C4B
Oil impregnations: C4A= J3, J2D, J5D Oil shows: C4A&C4B=J6
Cross-Section 2
Upper unit: lateral facies change Lower one: progradation (downlap) Oil impregnations: Upper U= J3, J1D, J4D Oil shows: Lower unit=J4D, J8D
Cross-Section 3
Upper unit: deeper facies Lower one: Dune/interdune geometries
Oil shows: Lower unit=J6, J8D
Field-scale Geological Model
Data Integration Joana#2D
