CHAPTER ONE
PROBLEM FORMULATION
1.1 Introduction
The production of formation sand is a major problem encountered during the production of oil and gas. Over 70 % of the world’s oil and gas reserves sit in sand formations where sand production is likely to become an issue during the life of the well (Osisanya, 2010). Sand production is typical of tertiary formations (with permeability of 0.5 to 8 Darcy) and older formations as they enter their mature stages of production due to poor completion and impact of depletion. Areas where severe sand production problems occur include Nigeria, Trinidad, Indonesia, Egypt, Venezuela, Malaysia, Canada tar sands and Gulf of Mexico. The reservoirs in these formations lie between 3,500 ft and 10,000 ft (subsea). Generally, the effects of sand production ranges from economics and safety hazards to well productivity and therefore has been an issue of interest to tackle in the petroleum industry. Some of these effects include erosion of downhole and surface equipment, pipeline blockage and leakage, formation collapse, damage to casing/production liner due to formation subsidence, and increased downtime. These devastating effects lead to more frequent well intervention and workovers generating additional needs for sand disposal particularly in offshore and swamp locations. The effects of sand production are nearly always detrimental to the short and or long term productivity of the well (William and Joe, 2003). In order to mitigate problems related to sand production new strategies are being continuously investigated, from prediction to control and management. The ability to predict when a reservoir will fail and produce sand is fundamental to deciding whether to use downhole sand control or what type of sand control to use (Bellarby, 2009).