Estimating rock mechanical properties of the Zubair shale formation using a sonic wireline log and core analysis

摘要

The Zubair Formation is the most prolific reservoir in Iraq, which is comprised of sandstones interbedded with shale sequences. Drilling boreholes in this formation has always been a challenge due to the weak nature of the shale sequence. Historically, over 90% of wellbore problems in the Zubair Formation are due to shale instability. To solve this problem, it is necessary to understand the rock mechanical properties and the response of shale. The main objective of this study is to develop local empirical correlations of rock mechanical properties that can be used to estimate a continuous profile of these properties throughout the depth of the Zubair shale formation directly from a wireline sonic log.