Pore morphology effect in microlog for porosity prediction in a mature field

By: , and 


  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS | Dublin Core


In an matured field, developed during the 1950s, no porosity logs were available from sources other than invaded zone resistivity Rxo . The microresistivity porosity is calibrated with the core porosity to yield an accurate estimate of the porosity. However, the procedure of calibrating the porosity with Rxo for a linear regression model may not be predictive without an understanding of the pore types in the reservoir interval. A thorough investigation of the pore types, based on the lithofacies description obtained from the core analysis, and its role in obtaining a good estimate of porosity is demonstrated in the Ogallah field. Therefore, the objective of this paper is to separate the porosity-microlog data into pore-type based zones with characteristic cementation exponents (m) in this multi-petrotype reservoir with a complex mixture of Arbuckle dolomite and sandstone rock. The value of m is critical in making estimates of water saturation. "Rule of thumb" values of cementation might lead to errors in water saturation on either the optimistic or the pessimistic side. The rock types in the Ogallah contain interparticle/intercrystalline, vugs and fractures distributed through the rock-facies, which influence the values of cementation factor. We use the modern typed well to shed light on the Archie's equation parameter values. Rock fabric numbers and flow zone indices have been identified for classification of dolomite and sandstone, respectively. The analysis brings out characteristic cementation factors for distinct pore types in the Arbuckle rock. The porosity predictions The analysis results also compliment the petrofacies delineation using LDA in this complicated rock layout as a quality control of the statistical application. The comparison between the predicted and core porosities shows a significant improvement over using a single m value for carbonates and sandstones which will lead to improved description of a matured field. Copyright 2011, Society of Petroleum Engineers.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Pore morphology effect in microlog for porosity prediction in a mature field
ISBN 9781618390936
Year Published 2011
Language English
Larger Work Title SPE Eastern Regional Meeting
First page 477
Last page 488
Conference Title Society of Petroleum Engineers Eastern Regional Meeting 2011
Conference Location Columbus, OH
Conference Date 17 August 2011 through 19 August 2011