Go Devil

Description

Slickline Go-Devil

Technical Description and Specifications

The Slickline Go-Devil is a specialized weight bar designed to be free-dropped down the wellbore. Its primary function is to mechanically impact and clear obstructions, typically used to sever a stuck slickline wire near the rope socket connection point, or to open specific shear-pin mechanisms on downhole tools.

Key Technical Specifications and Operation

• Function: To deliver a high-velocity, high-impact force to a specific target downhole, usually to:

  1. Shear a Stuck Wire: Impact the rope socket, shearing the wire or a designated weak point, enabling recovery of the main slickline unit while leaving the rope socket and tools behind for later fishing.

  2. Actuate Devices: Apply the necessary force to shear pins or impact surfaces on tools like safety valves or specialized shift sleeves.

• Design: A solid, heavy cylindrical body, often featuring a beveled or pointed leading edge to aid in centering and penetration of the obstruction. It is sized to pass freely through the tubing ID.

• Deployment: Deployed by free-dropping the tool into the well. The terminal velocity and kinetic energy ($E_k = 0.5 \times m \times v^2$) are determined by its mass, drag coefficient, and the length and viscosity of the fluid column it falls through.

• Critical Risk: Requires precise calculation of tubing ID restrictions to ensure the tool does not prematurely wedge or hang up downhole.

• Connection (Customizable):

  • While typically deployed without an active surface connection, retrievable Go-Devils can be fabricated with a fishing neck or profiled top sub (e.g., standard quick-connect or proprietary threads) to allow for later fishing retrieval if the primary impact attempt fails.

• Material (Customizable):

  • Standard construction uses high-density alloy steel (e.g., AISI 4140) to maximize weight and impact energy.

  • Custom material options are available, including Tungsten-filled variants to achieve maximum mass (impact energy) for a given OD, critical in high-viscosity or deep wells. NACE MR0175 compliant materials are available upon request for sour service environments.

• Critical Parameters (Customizable Size & Weight):

  • Tool OD and Weight: Custom fabricated to optimize the mass-to-clearance ratio. The OD must be sized accurately to ensure free fall through the smallest anticipated restriction.

  • Clients must specify the target tubing ID, minimum restriction, and the required impact energy (or calculated weight) when placing a custom order.

SEO Keywords (Targeted for Slickline Procurement)

Primary: Go Devil, Slickline Go-Devil, Wireline Cutting Tool (Free-Drop), Downhole Impact Bar, Slickline Shear Device.

Secondary: Slickline Severing Bar, Free-Fall Weight, Downhole Obstruction Clearing.