Freeze services are used to place a temporary pressure barrier (ice) in a well casing, annular space, tubing, drill pipe, spool, valve, or other wellhead pressure containing component when the use of conventional barrier options is not possible. In its simplest form, a freeze involves bringing a wellhead component to a very low temperature in order to transform the existing fluid within the wellbore component into ice, and this ice is utilized as a testable pressure barrier.
In recent years, Wild Well has worked with Texas A&M University to explore cryogenic freezing. Using liquid N2, or CO2, in combination with integral temperature monitors, an effective freeze can be safely and efficiently completed. The freeze process is monitored and temperature precisely maintained to ensure it is kept within recommended guidelines. Through the use of N2, or CO2, the freeze can be put into effect and held to isolate inoperable tree components. Once the freeze is established, a positive and/or negative pressure test can be completed to confirm the temporary barrier is in place, allowing repair operations. Within certain parameters, cryogenic freezes can be set across multiple strings of casing resulting in an effective temporary barrier in the innermost tubular.
In order to establish a freeze barrier, there must be a freezable medium (brine, water, mud, etc.) in the ID of the component. If there is flow, any void, or gas or hydrocarbon-based fluid present in the freeze area, a freezable medium must be injected into the ID of the component. This can be through a hot tap to a tubular or possibly through the tree assembly. When liquid hydrocarbons are present, Wild Well’s newly developed FreezeLITE, a special water-based fluid, can be injected into the freeze zone. FreezeLITE will displace hydrocarbon-based fluids and stay suspended in the freeze zone above the hydrocarbon-based fluid. This allows a freeze to be put into effect without having to remove the hydrocarbon-based fluids in the well – saving thousands of dollars in terms of product and time. FreezeLITE is non-hazardous and safe for onshore and offshore applications. Cryogenic Freezing is proven to be a quick, cost-effective, and safe solution when a temporary barrier in the wellbore/component is needed for completing remedial work at the surface. Wild Well offers three proprietary freeze application systems: Flex Wrap, Coil Line, and Aluminum Canister Freeze.
Three freeze application systems are currently available, including Flex Wrap, coil line, and aluminum canister freeze. Our team assesses each individual situation to determine which system is most appropriate.
|Cannister Freeze||Nitrogen||Aluminum Canister||Tubular or Linear Up to 9-5/8” Diameter|
|Flex Wrap Freeze||CO2||Freeze Jackets 2 3/8”-36”||Valve and Tree Components Up to 4-1/16” Pressure Rating Sizes|
|Coil Line Freeze||Nitrogen||Stainless Steel Flex Hoses||Valve, Tree, and Linear Components - Length of Coil Line as Required|