Sand production onset using 3D Hoek-Brown criterion and petro-physical logs: a case study

Sand production is a serious problem while oil and gas producing from unconsolidated formation. The reasons for such damage are the loss of the balance of the rock's stress in a drilling situation, create a momentum in the grain by fluid movement, reduction in reservoir pressure, and fatigue formation in the rock. Therefore, it is significant to forecast and evaluate the sanding onset of the wells with the intention of drilling and production condition optimisation. In this study, first, a geo-mechanical model based on the reservoir and petro-physical properties was established. Then, a new analytical shear failure sanding onset prediction model was derived on the basis of the three-dimensional Hoek-Brown failure criterion. Furthermore, the developed model was applied to the prediction of the critical drawdown pressure causing sand production in one of the wells drilled in one of the fields located in southwest Iran. Finally, the sensitivity of the relevant parameters with respect to the sanding onset in this well was evaluated. The results showed that the three-dimensional Hook-Brown model was a good fit with well number 19 of the Asmari field. Therefore, this criterion was recommended for the sand production analysis in this oil field.

Automated summary

Sand production is a serious problem in oil and gas production from unconsolidated formations, caused by stress imbalance, fluid movement, reservoir pressure reduction, and rock fatigue. A geo-mechanical model was established and a sanding onset prediction model derived, successfully applied to analyze a well in a field in southwest Iran.