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Geofluids
Volume 2017, Article ID 3179617, 12 pages
https://doi.org/10.1155/2017/3179617
Research Article

Real-Time Pore Pressure Detection: Indicators and Improved Methods

1Geomech Energy, Houston, TX, USA
2North China Institute of Science and Technology, Yanjiao, Beijing, China

Correspondence should be addressed to Jincai Zhang; moc.oohay@iacnijgnahz and Shangxian Yin; moc.621@30xhsniy

Received 6 June 2017; Accepted 1 August 2017; Published 27 September 2017

Academic Editor: Fengshou Zhang

Copyright © 2017 Jincai Zhang and Shangxian Yin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

High uncertainties may exist in the predrill pore pressure prediction in new prospects and deepwater subsalt wells; therefore, real-time pore pressure detection is highly needed to reduce drilling risks. The methods for pore pressure detection (the resistivity, sonic, and corrected -exponent methods) are improved using the depth-dependent normal compaction equations to adapt to the requirements of the real-time monitoring. A new method is proposed to calculate pore pressure from the connection gas or elevated background gas, which can be used for real-time pore pressure detection. The pore pressure detection using the logging-while-drilling, measurement-while-drilling, and mud logging data is also implemented and evaluated. Abnormal pore pressure indicators from the well logs, mud logs, and wellbore instability events are identified and analyzed to interpret abnormal pore pressures for guiding real-time drilling decisions. The principles for identifying abnormal pressure indicators are proposed to improve real-time pore pressure monitoring.