Lanny Schoeling

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CO2 Miscible Flooding In Mature Fields
Lanny Schoeling VP Engineering and
Technology Development
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Agenda

• History, Future Potential of CO2 Miscible
  Flooding
• Fields Types amenable to CO2 Miscible Flooding
• Advantages and Disadvantages in these Mature
  Fields
• Advantages include
• Vast Amounts of Production and Injection Data
• Geological Data (logs, wellbore histories, etc.)
• Disadvantages
• Problem Wellbores and Poor Past Operating
  Practices
• New Tools and Technology include
• Data Management and Geological Tools
• Simulation Tools
• Expandable Tubulars
• Conformance Remediation Technology
• Submersible Pump Program
• Summary

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US DOE Feb. 2006 Undeveloped Domestic Oil
Resources in USA
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CO2 EOR Growth
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SPE 18977 Performance of CO2 Miscible Flood
Field Projects
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Reservoir Criteria

• Reservoir Depth - 2000 ft or greater
• Oil Gravity (API) - 25 or greater
• Reservoir able to pressure up to MMP
• High Residual Oil Saturations
• Favorable Waterflood Characteristics
• Homogeneous Reservoir
• No Fractures or Thief Zones
• Possible Reservoir Problems
• Gravity Override

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Advantages and Disadvantages In Mature Fields

• Advantages
• Large amounts of Production and Injection Data
• Past Waterflood Response can assist in designing
  your future CO2 Flood
• Geological Data is available.
• Disadvantages
• Wellbore Problems
• Condition (Corrosion and Integrity (Good cement
  jobs) - ?
• Reservoir Rock around wellbore
• Poor Past Operating practices
• Over-pressuring of Reservoir Rock
• Past Fluid Injection

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New Tools and Technologies Available

• Well Data Entry Programs - converts well files to
  usable electronic files
• Dynamic injection and production software -
  common data entry formats
• Geological Platforms that accept common/standard
  formats data sets.
• CO2 Simulation Software
• Easy to use ---- CO2 Prophet
• More sophisticated software with great pre-post
  processors for ease of use. (Roxar-More, CMG-Gem,
  Ellipse, VIP, and more)
• Expandable tubulars to solve wellbore problems
  (corrosion, leaks, etc.)
• Conformance Remediation Treatments
• Gel Polymer Treatments

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Historical Background
Water Injection Ramps up in 1970
CO2 Inj. Starts 1971
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Well File Data Entry
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Utilizing Dynamic Production/Injection
DataConduct Streamtube Analysis to determine
Areal Sweep
Where channels exist, change patterns or change
BHP on wells to divert fluid to other locations
When Implementing the gel polymer treatment on
178-1, polymer channelled to two locations away
178-3 confirming this streamtube model.
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Contour maps of CO2
39-1 (South Platform Map) Location Map on CO2 Cum
HCPV Map
39-1
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Petrophysical Technique to Detect CO2
39-9 Modern Log 39-1 Profiles
80 Into Zone
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70s 80s 90s 00s
CO2
Spread Neutron/Density Porosity
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Fine Grid Segment Compositional Model Status
RMS Geostatistical Model Translated into a Fine
Grid Simulation Grid in More
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Mechanistic Pattern Simulation
CO2 Started at 67 Oilcut with 101 WAG
CO2 Started at 33 Oilcut with 101 WAG
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Expandable Product Line
Cased-Hole Liner System
Openhole Clad System
Openhole Liner System
FlexClad System
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Results from Gel Polymer Treatments
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Submersible Pumps SACROCThe Problem
High and Increasing Failure Ratio

• Technical Aspects
• CO2 flood with WAG. Highly variable
  downhole conditions
• Data from downhole pump sensors not
  collected, not analyzed
• No CO2 specific engineering, operating
  tools or practices.
• Low cost pump supplier, some used pumps

• Non Technical Aspects
• Multiple, disconnected, organization groups
• More than sixty people involved
• No written process, design protocol,
  operating policies.
• Imperfect communication, collaboration,
  organizational learning

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Submersible Pumps SACROC Steps and Results to
Date

• Steps to Date
• New supplier . No used equipment
• Target pump intake pressure above
  minimum CO2 low density threshold.
• Cross functional team formed adopted
  managed process approach.
• Now deploying CO2 specific analysis tools
  and pump designs

• Results to Date
• Failure ratio drastically reduced
• More than 300 pumps installed by new
  supplier
• Downhole sensor data collected for 90 of
  wells. Forty SCADA connections to
  producing wells.
• CO2 specific engineering tools operating
  guides defined. Deployment underway.
• Managed process deployment underway.

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Summary

• Many Mature Fields exist with Large Potentials
  for EOR such as CO2 Injection
• Tools and Technology exist which if used
  correctly can increase the value of these fields
  substantially.
• Software Tools (Data Handling and Geological and
  Eng. Sim.)
• Wellbore Restoration Technology
• Chemical Technology (Gel Polymers, etc.)
• Trained and Experienced Professionals are very
  important in implementing these projects