Dissolvable Check Valves for Improved Oilfield Completions
Publication Date: 2013-Apr-15
The IP.com Prior Art Database
A better solution is an interventionless check valve that will disappear. A disappearing check valve will provide the fluid control that is needed during installation, during wellbore cleanup, and during gravel packing as well as disappearing completely once production commences.
Check Valves for Improved Oilfield Completions
In a typical wellbore completion, production tubing serves as a conduit for fluids to travel from the formation to the surface. The production tubing has inlets near the formation to allow the production fluid to enter the tubing. While these inlets are critically important during production, these inlets are unnecessary and often are detrimental prior to production. An example of a typical wellbore completion is shown in Figure 1 showing a wellbore with inlets in the deviated section.
Figure 1: Dual completion featuring inlets from the formation into the tubing.
The inlet paths can be damaged during installation and are detrimental during wellbore cleanup and gravel packing. Blocking the tubing inlets allows for more a reliable installation, for more effective wellbore cleanup, and for a longer and more reliable gravel pack. During installation, the inlet pathways can be clogged with filter cake, drill mud, or other solids. Sometimes during installation there are extended periods of time without circulation and these muds can become increasingly viscous and exhibit an increasing shear strength. The result is that the muds can become locked in the inlet and can be difficult to be cleared by the production pressure.
During wellbore cleanup and during gravel packing, the inlet pathways allow the injected fluids to prematurely enter the tubing. In wellbore cleanup, the injected acids prematurely entering the inlet paths and are not circulated along the entire length of the tubing which results in a less efficient wellbore cleanup. During gravel packing, the carrier fluids can prematurely enter the tubing through the inlet paths and can result in a reduced amount of liquid supporting the gravel. This loss of carrier fluid results in dehydrating the gravel pack and has the potential to form bridging in the gravel pack and potentially to create voids in the gravel pack. Both of these detrimental behaviors limit the quality of the gravel pack and limit the length of hole that can be gravel packed. All of these detrimental behaviors can be mitigated if the inlet paths were closed until production was ready to commence.
There have been previous products to block the inlets between the tubing and the formation. Halliburton’s galvanic time release plugs[i] create a complete seal in the tubing inlets and this seal is designed to disappear with time. As a result, the galvanic time release plugs provide a seal during the installation and gravel packing but is no longer present when production commences. Halliburton’s check valve system[ii] is another product that seeks to address the issue of premature flow through the tubing inlets. The check valve system uses a check valve to restrict the flow through the tubing. Additionally, sliding sleeves have been used to block the inlets. Sliding sleeves are typically shifted with a wellbore intervention, such as with...