POWER has established a complete Sand Control technical system, and successfully implemented in many oilfields in China and overseas.
Common Sand Control Techniques
– Gravel packing
– Frac Packing
– Slotted liners or screens
– Consolidated gravel
– Chemical consolidation
l Some wells require filtration systems in order to keep the wellstream clear of sand. In addition to running a casing with a liner, gravel packing is used to prevent sand from entering the wellstream.
l More complicated than cementing a well, gravel packing requires a slurry of appropriately sized pieces of coarse sand -- or gravel -- to be pumped into the well between the slotted liner of the casing and the sides of the wellbore. The wire screens of the liner and the gravel pack work together to filter out the sand that might have otherwise entered the wellstream with the hydrocarbons.
l Frac-Packing is general term applied to process of combining a hydraulic fracture with a gravel pack. It provides both for Sand Control and for Reservoir Stimulation – NWD removal(Near-Wellbore-Damage)
l Main purpose is to provide the optimum combination of productivity improvement through damage bypass, and well life improvement through effective sand control
l Significant increase in propped fracture conductivity to the reservoir fluid as compared to the conductivity prior to the treatment (Dimensionless Conductivity)
l Mainly applied in cased hole completion.
Slotted liners or screens
l Slotted liner or screen used as a down hole filter
l Best results in uniform, large-grained formations
l Plugging and erosion of screens is main risk
l Widely applied in open hole horizontal wells with mixed success
l Consists of gravel pack sand or proppant coated with a thin layer of resin that cures when exposed to heat.
l A slurry of resin coated gravel is pumped to fill voids behind casing, perforation tunnels and wellbore across entire perforated interval.
l After curing, the gravel in the wellbore is drilled out, leaving gravel in perforations and outside casing to control sand production.
l Goal is to inject plastic resins into the formation to provide increased compressive strength while maintaining acceptable permeability.
l Treatment objective are:
– Cover entire perforated interval
– Coat all sand grains with resin
– Concentrate resin at grain contact points
– Leave pore spaces open