The mechanical strength of a reservoir formation is the most crucial information required for predicting sand production and recommending sand control completion. The only reliable technique, so far, to obtain the formation strength quantitatively is to perform laboratory tests on core samples. The laboratory tests require substantial volumes of cores which, in most cases, are not available. In this study, we present a new method to avoid this restriction. The significance of this approach is its simplicity and efficiency in constructing a reliable mechanical failure envelope. The key results of this study, based on measurements on a variety of sandstones, are:
Sandstone formations are characterized by a single normalized failure envelope. This universal curve makes it possible to construct the failure envelope for a sandstone formation from the knowledge of critical pressure.
There exists a correlation between the critical pressure and the compressional wave velocity (at equivalent depth of burial).
The failure envelope for a sandstone formation can then be constructed simply from compressional wave velocities. These velocities are generally accessible from conventional logging data.