The Lead Impression Block in oil and gas is designed to give an imprint of the top of a fish in the hole to help determine the condition and position of the top of the fish. The Impression Block can also be used to give clues on how to retrieve an unknown fish in the well, and used in wireline fishing operations to identify obstructions. It is also can be run to get the dimensions of the casing collapse zones.
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There is a tapered type that is designed to check damage inside internal fishing necks . Such runs to be effective, we shall always clear the bottom surface before running LIB. Also, Such a tool shall be run slowly through the wellhead and completion string. In fishing operations, once you have confirmed contact with the top of the fish, the lead blocks should be set down carefully and only one jar will be enough to take such an impression of the fish. More than one impression will cause confusion. Also, heavy downward jarring (check also : Drilling Jars) will cause the lead to extrude out and may cause interference with the retrieval of the block through any restrictions on the hole.
Lead Impression Block Operations
It may be run on wireline, coil tubing, or drill pipe. An impression is obtained by simply setting down weight onto the fish. The Lead Impression Block is then pulled out of the hole and inspected by the oil and gas fishing tool operator.
Baker Hughes Block Features
- One-piece construction with a cast lead head
- Can be reworked for multiple runs
- Available in many sizes for a wide range of impression possibilities
Bowen Block Features
Bowen Impression Blocks consists of a soft lead insert in the steel housing lower end. To use a Bowen LIB, you can follow this procedure:
- Lower the tool into the well to be run on the fishing string lower end.
- After there is a contact with the top of fish, lower the string weight straight down and never make any rotation against the fish
- After POOH with fishing string, the impression in the lead block will reveal the condition of the fish.
It is also available in two styles:
- Solid Impression Block (conventional type)
- Watercourse Impression Block: This type have watercourse through tool which is used to wash off top of fish to get good impression.