Lesson 12

1. Lesson 12 Selecting an Appropriate Technique Read: UDM Chapter 4 pages 4.1-4.54

2. Harold Vance Department of Petroleum Engineering Selecting an Appropriate Technique Potential Applications and Candidate Technique Technical Feasibility Economic Analysis

3. Harold Vance Department of Petroleum Engineering Required data for UBO Candidate Identification: Pore pressure/gradient plots Actual reservoir pore pressure ROP records Production rate or reservoir characteristics to calculate/estimate production rate Core analysis

4. Harold Vance Department of Petroleum Engineering Required data for UBO Candidate Identification: Formation fluid types Formation integrity test data Water/chemical sensitivity Lost circulation information Fracture pressure/gradient plot

5. Harold Vance Department of Petroleum Engineering Required data for UBO Candidate Identification: Sour/Corrosive gas data Location topography/actual location Well logs from area wells Triaxial stress test data on any formation samples

6. Harold Vance Department of Petroleum Engineering Poor candidates for UBD High permeability coupled with high pore pressure Unknown reservoir pressure Discontinuous UBO likely (numerous trips, connections, surveys) High production rates possible at low drawdown

7. Harold Vance Department of Petroleum Engineering Poor candidates for UBD Weak rock formations prone to wellbore collapse at high drawdown Steeply dipping/fractured formation in tectonically active areas Thick, unstable coal beds

8. Harold Vance Department of Petroleum Engineering Poor candidates for UBD Young, geo-pressure shale H2S bearing formations Multiple reservoirs open with different pressures Isolated locations with poor supplies Formation with a high likelihood of corrosion

9. Harold Vance Department of Petroleum Engineering Good candidates for UBD Pressure depleted formations Areas prone to differential pressure sticking Hard rock (dense, low permeability, low porosity) �Crooked-hole� country and steeply dipping formations

10. Harold Vance Department of Petroleum Engineering Good candidates for UBD Lost-returns zones Re-entries and workovers (especially pressure depleted zones) Zones prone to formation damage Areas with limited availability of water

11. Harold Vance Department of Petroleum Engineering Good candidates for UBD Fractured formations Vugular formations High permeability formations Highly variable formations

12. Harold Vance Department of Petroleum Engineering Good candidates for UBD Once the optimum candidate has been identified, the appropriate technique must be selected, based on much of the same data required to pick the candidate.

13. Harold Vance Department of Petroleum Engineering Candidate Decision Tree