Sand production and sand prediction

"Seventy percent of the world oil and gas reserves are contained in sandstone reservoirs where sand production is likely to become a problem at some point during the life of the field..." report the experts of the Society of Petroleum Engineers (SPE). Sand production occurs during the hydrocarbon production from a well when the reservoir sandstone is weak enough to fail under the in situ stress conditions and the imposed stress changes due to the hydrocarbon production. The oil or gas flow transports the failed rock causing a variety of problems ranging from erosion of the surface facilities, to well integrity, and sand disposal. On the other hand, limited sand production has been proven to increase the productivity of a well and when tolerated it may eliminate altogether the need for sand control.

SINTEF Petroleum Research has had continuous research activity in sand production prediction and control for more than 20 years with a series of joint industry projects and various other research projects and studies. Among the results from this research are:

• Sand production and hollow cylinder test system with one or two-phase oil-water fluid flow
• Polyaxial test system for borehole stability under fully anisotropic stresses
• Sand production in cavities with gravel pack or screens
  

Theoretical and numerical models

• Constitutive model for the poromechanical behavior of soft-weak sandstones for sand production and borehole stability
• Constitutive model for coupled erosion-mechanical behavior of soft-weak sandstones for volumetric sand predictions
• Numerical finite element model for bore stability, sand production initiation and volumetric sand production predictions
• Classification of sandstones in terms of sand potential
• Mechanics of sandstone interaction with sand control tools such as screens and gravel packs
• Effects of production parameters, rock properties and water cut on sand production initiation and volume of produced sand or sand production rate
• Engineering tool for sand production prediction

In 1998 the three-year multi-client project, "Sand production in open hole completions", was completed with a sand production workshop in Diablerets, Switzerland. This project was followed by the three-year multi-client project, "Volumetric sand production", which is focusing on volumetric sand production prediction and well productivity. This last project was extended into the ongoing phase "Volumetric sand production II", which looks into unconsolidated reservoirs, gas reservoirs and water-producing reservoirs and post-failure modeling of sanding, in effect establishing a bridge between sand production and sand transport research.

Contact: Pierre Cerasi