This dummy valve is “smart”
Gas lift is an artificial lift technology that uses gas injected (generally) from the surface through an opening in the production tubing to lower the density of the liquid column, allowing the well to be produced. In most modern completions, gas enters through one or more gas lift valves placed in side pocket mandrels. The use of side pocket mandrels obviates the need for a major workover to replace a valve. Fluid production rates generally increase with volumes of injected gas up to a certain point, at which the pressure drops associated with the produced gas offset the benefits.
Gas lift is one of most common forms of artificial lift for offshore wells because of the availability of high-pressure gas, relative downhole simplicity, flexibility, reliability, and ability to operate over a large range of rates.
The ideal depth for injecting gas may change with time as the well’s pressures, fluid type, and productivity change. Multiple gas lift valves (GLVs) may be installed at different depths, and the opening characteristics of these valves may need to be modified over the life of the well. In many systems, dummy valves are loaded in side pocket mandrels to isolate the annulus from the tubing where pressurization is required to test the tubing, test the annulus, set a hydraulic packer, or activate an isolation device.
If the well then requires gas lift to unload the completion fluid or to assist the well to flow, wireline intervention is required to remove the dummy valves and install the live gas lift string. This can be time-consuming and can pose risks to existing infrastructure. Production is also delayed while a new live valve unit is installed.
The Baker Hughes Transmatic™ Gas Lift Valve, which uses nanotechnology in its temporary internal plug, can be installed in wells to function as a “smart” dummy valve. The Transmatic valve automatically converts to a live valve through disintegration of the temporary internal plug. This completely eliminates wireline intervention and workover costs to replace dummy valves with live valves.
The key to the success of Transmatic GLVs is the smart nanostructured composite material, InTallicTM, developed and patented by Baker Hughes materials scientists and used in the internal plug. InTallic material is lighter than aluminum but as strong as mild steel. It is chemically resistant to drilling mud, slightly reactive with fresh water, and will disintegrate in salt water in 12-50 hours, making it an ideal designer material, perfectly engineered for offshore gas lift valve application.
The self-disintegration of the Transmatic plug after a short period of time completely eliminates the need for change-outs of dummy valves by wireline operation and allows unloading and immediate production of these wells under optimized gas lift conditions. This technology eliminates the need to wait for wireline crews and can eliminate many costly production delays. Transmatic GLVs also eliminate cement damage to GLVs in cement-through completions. The damage can junk a well or leave it incapable of gas lift optimization.
Readers can download this pdf to read about a successful application of this technology in Thailand. The technology was a finalist for Best Production Technology in the 2012 World Oil Awards.
Most of the information for this entry comes from Dr. Zach Xu, one of the Baker Hughes Material Science researchers.
Dr. Zach Xu is the Manager of the Advanced Composite Science group at Baker Hughes. Zach leads the development of Disintegrable InTallic Material, a Baker Hughes flagship materials technology that is used in the InTallic Frac Ball and seat and Transmatic Gas Lift Valve, and is being lab and field tested in other downhole tool applications. Dr. Xu’s areas of research interest include advanced engineering materials and oilfield tools, mechanical and physical metallurgy, nanostructured materials, material characterization and failure analysis, surface modifications and coatings, welding and welding metallurgy, laser materials science, and processing. Zach joined Baker Hughes in January 2009 with extensive R&D and project management experience on advanced engineering materials and oilfield tools. He previously worked at the U.S. DOE Argonne National Laboratory and taught at Southwest Petroleum Institute of CNPC. Dr. Xu received his Ph.D. in Material Science & Engineering from Illinois Institute of Technology, MSc in Materials Science from University of Southern California, and BSc in Oilfield Mechanical Engineering from SWPI/ChongQing University. Zach is a certified Project Management Professional (PMP).