Permeability Evaluation of Zubair Formation Using Well Logs
Alameedy, Usama S.*1
(1) Wireline & Perforating Services, Halliburton - Drilling & Evaluation Division, Basrah, Iraq.
This study is focused on the evaluation of formation permeability for a sandstone reservoir in three southern Iraqi oil fields which are Zubair, North and South Rumaila at Zubair formation. Methods of determing permeability form logs are reviewed. A case history is presented showing how an optimum empirical relationship to predict permeability can be developed, with commonly available core and log data for a particular formation and area. Verifiable and accurate permeability prediction from well logs in a well with no core measurement data are presented by improved log derived permeability relationship. Sandstone grain size and sorting, and hence permeability are often related to the amount of interstitial silt and shale and this in turn may be reflected in the natural radioactivity. Because of this, in some areas permeability of sandstone can be estimated from carefully calibrated gamma ray curves as the proposed relationship (√k=1/2 Exp(4.5φ2+4 (1-IG))). For the South Rumaila and Zubair fields it is found that the permeability is a function of porosity, irreducible water saturation and volume of shale. It is also found that the correlation coefficient between predicted and observed permeability for the above function is increased by taking the square root of the permeability (√k).
AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain