Title: A novel approach for estimating geopressure in unconventional shale play

Authors: Alberto Lopez Manriquez; Kamy Sepehrnoori

Addresses: The Wayne H. King Department of Chemical and Natural Gas Engineering, Texas A&M University-Kingsville, 700 University Blvd., Kingsville, TX 78363-8202, USA ' Petroleum and Geosystems Engineering Department, The University of Texas at Austin, 200 E. Dean Keeton St., Stop C0300, Austin, TX 78712-1585, USA

Abstract: This paper presents the results of the application of a novel approach to estimate geopressure in an unconventional shale play using the diffusivity theory and information from well logs. Some of the most recurred post-drill methods to estimate pore pressures use empirical approaches carrying with them the drawbacks that it implies. Pore pressure is computed along the depth of investigation in a well located in the Southwest part of the Eagle Ford. The recorded rock properties from well logging are introduced into the solution of the diffusivity equation as 'normalised values' and a 'non-strict inverse method' is implemented to obtain the pore pressure distribution. The results documented here demonstrate that our approach is effective and reliable when comparing estimated pore pressure values against calibration data. The methodology provides a valuable tool to identify sources of abnormal pressures other than disequilibrium compaction such as secondary compaction or diagenesis. [Received: December 21, 2015; Accepted: October 5, 2016]

Keywords: geopressure prediction; diffusion; diffusivity equation; pore pressure; consolidation; abnormal pressure; secondary compaction; reservoir description; well logging.

DOI: 10.1504/IJOGCT.2018.090971

International Journal of Oil, Gas and Coal Technology, 2018 Vol.17 No.4, pp.391 - 411

Received: 21 Dec 2015
Accepted: 05 Oct 2016
Published online: 05 Apr 2018 *

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