Flow Regimes Diagnostic Plot for well test analysis

Well test flow regime

1. Reservoir and Geometric Flow Regimes Diagnostic Plot © Copyright 2003 Schlumberger. Unpublished work. All rights reserved. This work contains confidential and proprietary trade secrets of Schlumberger and may not be copied or stored in an informational retrieval system, transferred, used, distributed, translated or retransmitted in any form or by any means, electronic or mechanical, in whole or part, without the express written permission of the copyright owner.

2. Outline Importance to Schlumberger Time regions. Flow regimes. Factors that affect pressure response in early time. Boundaries that affect pressure response in late time.

3. Objectives Describe the diagnostic plot. State the importance to Schlumberger Identify the Time regions. Identify the Flow regimes and their characteristic slope. List 3 factors that affect pressure response in early time. List 3 boundaries that affect pressure response in late time.

4. Importance to Schlumberger Engineers Allow us to use the proper Reservoir Model in the WELLTEST TM software Improve our stimulation design.

5. Reservoir Flow Regimes 1. Transient flow: Pressure disturbance has not reached the reservoir boundary and the reservoir seems infinite. Infinite-acting radial flow (IARF) occurs during this time. dP/dt = variable 2. Pseudo-steady state: Effects of the reservoir boundary are felt. Pressure starts depleting, however, rate remains same as long as the pressure drawdown remains the same. dP/dt = constant 3. Steady state: Pressure distribution uniform throughout the reservoir and the average reservoir pressure does not change with time. dP/dt = 0

6. The Log-Log Diagnostic Plot: Pressure Change, Derivative vs. Δt Elapsed time, hrs Pressure change, derivative, psi

7. Time Regions on the Diagnostic Plot Elapsed time, hrs Early-time region Middle- time region Late-time region Pressure change, derivative, psi

8. Geometric Flow Regimes Common geometric shapes Different flow patterns may appear at different times in a single test Flow regimes follow sequence within model

9. Volumetric Behavior

10. Radial Flow

11. Linear Flow

12. Bilinear Flow

13. Spherical Flow

14. Flow Regimes on the Diagnostic Plot Wellbore storage Spherical flow?? Radial flow Recharge PSS?

15. Flow Regimes and the Diagnostic Plot: RSB

16. Exercise 1: Flow Regimes and the Diagnostic Plot Type of well, geology…?

17. Fracture Linear Bilinear Formation Linear Elliptical Pseudoradial WBS Unit slope in all wells. ½ slope but normally hidden during WBS ¼ slope in finite cond. Fracs. wk f estimated if k is known ½ slope in infinite cond. fracs. x f estimated if k is known. Transitional period 0 slope seen in infinite cond. fracs. E stimate k and s. Skin factor used to estimate x f

18. Objectives Describe the diagnostic plot. State the importance to Schlumberger Identify the Time regions. Identify the Flow regimes and their characteristic slope. List 3 factors that affect pressure response in early time. List 3 boundaries that affect pressure response in late time. Questions and Comments!