cam mcburney and richard baker gca canada (a division of baker hughes)
TRANSCRIPT
Field Performance of the Weyburn CO2 Miscible Flood and Factors
Affecting CO2 Performance (Naturally Fractured Reservoirs)
Cam McBurney and Richard Baker GCA Canada (a division of Baker Hughes)
Presented at the 17th Annual CO2 Flooding Conference
December 8-9, 2011
Midland, Texas
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Overview
• Executive Summary• CO2 miscible floods in NFR
– Midale/Weyburn Canada (horizontal CO2 + waterflood)
• Spraberry Tracer Tests and Waterflooding• What is critical knowledge needed to
characterize NFR for CO2 ?• Conclusions
Executive Summary
• In Weyburn CO2 and waterflood (Canadian) –– moderatemoderate fracture connectivityWaterflooding, horizontal wells and CO2 flooding are
successful.• In Spraberry
– very long range long range high fracture connectivity and stress sensitivity
• Most injection processes in NFR are controlled by;
Long range fracture connectivity
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Weyburn / Midale Fracture Characterization
Horizontal CO2 miscible floodSPE 63286
JPT OCTOBER 1993CIM 98-88
CIM 96-03-03CIM 2007-31WPC 18-986
Cenovus Web site
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Calgary, Alberta
Weyburn field
Cenovus web site
Weyburn Midale Location
Current well countsTotal Well Count = 807Hz Well Count = 488Injection well Count = 283
NE – SW fracture trends
Weyburn Unit Reservoir Parameters
* Matrix ** variation within unit
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More intenselyfractured
NE to SW fractures
~3ft fracture Spacing; Marly
~1ft fracture Spacing; Vuggy
Weyburn Unit - Midale Formation Full Field
Start of CO2flood
CO2 +Hz well
Hz well
Weyburn; Midale Formation Full Field Inj
Start of CO2 flood
1980’s vert infill
1990’s horizontalwells
Weyburn; Full Field Well Counts
CO2Injection
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Weyburn; Full Field – Injector Type
EPIC’s analysis of CO2Incremental Oil Rate~ 25 MSTB/d
Original Oil in PlacePhase OOIP from
Application(e6m3)
OOIP from Application
(MMbbl)
Phase 1A 29.0 183Phase 1B 7.6 48Phase 1C 17 107Phase 1D 18.5 117
Weyburn Midale Phase 1A
Map of Weyburn CO2 PhasesPhase 1A
Phase 1B
Phase 1C
Phase 1D
Phase 1A Composite Plot
Bubble Plots-Phase 1 AWater Cum Produced = 470 MMBblOil Cum Produced = 135 MMBbl
Water Cum Injected = 580 MMBblCO2 Cum Injected = 46,000 MMBbl (257 Bcf)(Injected water bubbles have a multiplier of 100)
Weyburn Phase 1A Production
Weyburn Phase 1B Production
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Start of CO2 Flood
Start of Water Flood
Weyburn Phase 1C Production
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Phase 1D (not enough data to do a decline)
Start of Water FloodStart of CO2 Flood
Incremental Oil Recovery (Epic’s interpretation) @ initial reservoir pressure and temperature
CO2 Response Examples
90’s Infill Hz Well• Drop in watercut/increase
in oil rate with CO2 b/t
Original Vertical Well• Drop in watercut/increase
in oil rate with CO2 b/t
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Recap for Weyburn Unit
Successful Waterflood≈
1980’s vertical well infills
Horizontal wells CO2 flooding
Incremental recovery factor due to CO2 flooding 12-20% OOIP
Total UFR >50%
What was the critical data? (in my opinion)
Lack of high connectivity fractures determined from production + injection testing
Interwell tracer
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Spraberry West Texas Waterflood CO2 pilot
(DOE/Pioneer Natural Resources)
SPE-39623SPE – 35469SPE – 71635SPE – 71605
David SchechterSchechter, D.: “Waterflooding and CO2 Injection in the Naturally Fractured
Spraberry Trend Area,” JCPT (October 2002)John Lorentz
Glasscock Co
Reagan CoUpton Co
Midland Co
Martin Co
Spraberry Trend Area
8-10 MMMbbl=OOIPDiscovered in 1949Sandstone Stress sensitiveTight low matrix permeability (keff <0.1 md)URF <15%
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Tests Conducted
Vertical and horizontal well core
• Outcrop• Pulse, PBU and fall off test• FMI (fracure logs)
Production decline analysis
Step rate
CO2 pilot
Interwell tracer
• ( Pilot - 9 years)
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O'Daniel O'Daniel O'Brian
O'DanielO'Daniel Brunson Boone
O'BrianPowellFloyd
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B-1
D-1
C-1
5
7
12
9 13
10
63
9
8 12
7
A-1
B-11
A-5
BooneE-1 A-6
A-3 A-7
32
12
8W
34
6
1
24
31
36
26
D-1
19
13
30G-1
C-2E-1
BooneA-1
D-1 A-1
F-1
C-1
C-11
D-1
3 2
47
25
29
37
46
C-1
28
45
38
39
40
48
14
41
43
4950
44
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N
Pilot Area Map
Pilot Area
Well Oil Response to Waterflood
1 mile
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SPE 71635
Tracer Test Results
Section lines~1 mile
Tracer Travelled2 miles in(1-3 days)
WHAT DO I NEED TO DO TO UNDERSTAND RESERVOIR FLOW AND CO2 FLOW?
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Communication Analysis
– We use Communication Analysis (signal processing) to see fracture connectivity
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objective
Communication Analysis (signal processing)
But the Extremes of the Data Set can Sometimes Control Injection Process
36Fracture connectivity (distance)
Number ofOccurrences
Average “bulk” properties
“outliers” or extremes
Communication Map
• Need a communication map or if too many zoom in view
• Example;
Early Waterflood History
We know from tracer tests offset Field that lateral fracture Connectivity is not that long <300ft
Weyburn Midale Phase 1A Communicating Well Pair
Injector
Producer
Injector
Producer
Weyburn Midale Phase 1A Communicating Well Pair
Producer
Injector
Weyburn Midale Phase 1A Communicating Well Pair
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Conclusions from Oil Recovery Point of View for CO2 Injection Processes
Spraberry (West Texas)Long connectivityStress sensitivity
WeyburnModerate fracture connectivitySuccessful; waterflood, hz wells, CO2 flood
The best way for brownfields is through communication analysisPressure pulseProduction data