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Calibrating Fracture Gradients—An Example Demonstrating Possibilities and LimitationsNormal access

Authors: S. Wessling, J. Pei, A. Bartetzko, T. Dahl, B. Wendt, S. Marti and J. Stevens
Event name: IPTC 2009: International Petroleum Technology Conference
Session: World Energy Challenges: Endurance and Commitment
Publication date: 07 December 2009
Organisations: EAGE
Language: English
Info: Extended abstract, PDF ( 783.15Kb )
Price: € 20

The fracture gradient is the upper boundary for the annular mud pressure while drilling and is one important parameter for
wellbore integrity. Its calibration using reliable data such as Leak-off-Tests (LOT) and events such as mud losses is essential
and can save the operators large amounts of money. Mud losses are often encountered when the annular pressure exceeds the
fracture gradient. Such an event can thus be useful to re-calibrate the fracture gradient in real-time in order to circumvent
additional losses while continuing drilling. However, analysis of causes for losses and the resulting delivery of proper
calibration data have rarely been reported in the past. In most cases, losses were analyzed after drilling, and the information
gained from this analysis has been used to plan future wells.

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