Definition of Soft Sand Low unconfined compressive strength (UCS). Low Young’s modulus (E). Poro-plastic compressive behavior (low cohesion). Poor core integrity, core wash-out during lab tests Sand production and wellbore stability problems. Stress dependent porosity and permeability.

Formation Failure in Soft Sand Cavity Collapse. Backflow. Crossflow. Water Hammer Effects. Injectivity Decline due to Sand-Filled Perforations.

Design Criteria for Soft Sand Pressure Charged Wellbore Area. Solid Flow in Two Directions.

Completion Methods for Water Injection Wells Very weak consolidated formation from top to bottom. Gravel pack. Open hole completion with a pre-packed screen if zone isolation is not required and there is a narrow grain size distribution. Weakly consolidated formation, low injection pressure. Selective perforation with a propped hydraulic fracture Selective perforation with a frac pack, without a screen Weakly consolidated formation, high injection pressure. Selective perforation with a high injection pressure. Injectivity enhanced by thermal cracking. Consolidated formation with limited weak zones. Selective perforation Uniformly strong formation. Open hole completion, no screen Perforated completion with or without additional stimulation

Completion Methods for Water Injection Wells In Weak Formations Gravel/Frac Packing. Open hole with a screen or a pre-packed screen. Perforation with a propped hydraulic fracture or thermally induced fracture. Selective perforation.