Scope of Application

This technology is suitable for offshore and onshore formation sand control when sand production is caused by unconsolidation, high oil and gas drainage pressure, high viscosity crude oil, depleted zones and incursion of extraneous fluids. For the gravel packing in the open holes, the size of the hole must exceed 6-1/2"; and for gravel packing in the screen of casing, the size of the casing must exceed 5-1/2".

Technical Principle

Stand-alone screen sand control mainly depends on the gap spacing created when the screen was manufactured, which is able to keep out  sand particles bigger than the gap spacing, however, formation sand particles smaller the gap spacing can still pass into the well. Different types of screens can be chosen according to various sand producing tolerance and cost budgeting.

Gravel packing technology is using ceramic proppants to fill the space between the screens and the formation; therefore, ceramic proppants with size bigger than the screens’ spacing will not enter into the shaft while smaller spacing between ceramic proppants will ward off formation sand with different sizes, so as to build the second filter screen. And the third filter screen is built by the accumulation of the formation sand with different sizes outside the ceramic proppant layer to ward off much smaller formation sand particles.

Diagram of Packer Screen Tools

Assembly Diagram for Gravel Packing Service Tools

Main tools:

① Top packer assembly – setting pressure: 3500 psi.

② Screen – wire wrapped screen with adjustable wire-winding spacing and big open area which can be up to 10%.

③ Bottom sump packer assembly – using hydraulic setting with temperature resistance of 149℃；

④ Service tool assembly – switchable gravel-pack sliding sleeve which can provide 2-3/8" return passage.

Technical Features:

(1)Effective formation sand control with the period of validity above 180 days;

(3)Safe and reliable with mature technology application.

Service Ability and Performance:

As of June 2013, DOT has completed sand control for 72 wells domestically with 100% effective rate. Operations include several formation sand control processes, for example: stand-alone screen sand control, high rate water pack (HRWP) sand control, micro frac-packing sand control, frac-packing sand control and open hole horizontal well gravel-packing sand control.