Lead Impression Block

Description

Lead Impression Block (LIB)

Technical Description and Specifications

The Lead Impression Block (LIB) is a critical non-fishing diagnostic tool used in slickline and wireline operations. Its sole function is to obtain a physical imprint of the top profile, condition, size, and orientation of a downhole obstruction (“the fish”). This impression is vital for accurately selecting the correct subsequent fishing tool (e.g., spear, overshot, skirted finder).

Key Technical Specifications and Operation

• Function: Diagnostic retrieval of the downhole obstruction profile to characterize the fish before initiating mechanical engagement.

• Design: Consists of a body (top sub) attached to a base plate that holds the primary impression medium. The medium is a solid, cylindrical block of pure, soft lead (or a high-density, impression-grade polymer for certain applications).

• Impression Medium: The lead is designed for maximum malleability and minimal recoil. The cleanliness and composition of the lead block are paramount for obtaining a clear, undistorted imprint.

• Operation: The LIB is run downhole and gently set down onto the top of the obstruction. Minimal weight is applied to deform the soft lead base against the fish profile. The tool is then retrieved without any jarring to preserve the impression. Analysis of the retrieved lead reveals:

  • Diameter of the fish.

  • Concentricity of the obstruction.

  • Presence of profiles (e.g., threads, breaks, uneven surfaces).

  • Relative hardness (indicated by the depth of the impression).

• Connection (Customizable):

  • Standard interfaces include proprietary slickline pin threads (e.g., $15/16″-10$ UN, $1-1/16″-10$ UN).

  • Custom order connections are available to ensure seamless integration with non-standard fishing string threads and proprietary quick-connect systems.

• Material (Customizable):

  • Tool Body: Standard construction uses high-strength alloy steel (e.g., AISI 4140).

  • Impression Medium: While pure lead is standard, custom polymer blocks or specific lead alloys are available for ultra-high temperature wells or environments where lead contamination is a concern. NACE MR0175 compliance applies to the tool body and subs.

• Critical Parameters (Customizable Size):

  • Base OD and Length: Must be closely matched to the target tubing ID to maximize the diameter of the impression possible. Standard ODs range from 1.5″ up to 5.5″.

  • Custom base ODs are fabricated to meet exact dimensional requirements for optimal coverage within specific tubing ID and restriction constraints. Clients must specify the target tubing ID and the required impression diameter when placing a custom order.

SEO Keywords (Targeted for Slickline Procurement)

Primary: Lead Impression Block (LIB), Downhole Diagnostic Tool, Slickline Fish Profile Tool, Wireline Impression Sub.

Secondary: Wellbore Obstruction Profiling, Soft Lead Impression Tool, Fishing Diagnosis Equipment.