Game Changing Technology Developments for Safe and Cost Effective Determination of Free Point in Horizontal and Vertical Wells
Authors: Kessler Calvin W. , Hill JIm Taylor , Weiser Jerry 
Published: July 2010

The Halliburton Free Point tool is a game-changing technology in the determination of the free point/stuck point in support of drilling and well abandonment operations. The identification of the free point in drill collars, drillpipe, tubing, or casing is critical for successful drilling and pipe recovery or well abandonment operations. A new logging tool is available that will cost effectively identify the free point. Case histories have shown rig time reductions in excess of 50% when compared to legacy free point methods. The tool uses the property of steel called the magnetostrictive effect, by which the magnetization of the steel is modified when it is subjected to stress.

The procedure for using the new tool requires two logging passes. The first logging pass creates a small magnetic field on the pipe and records the pipe magnetization information with the pipe in a neutral weight condition. The second logging pass records the magnetization information after tension or torque has been applied to the pipe and released. When torque or tension is applied to pipe that can be stretched or torqued, the magnetostrictive properties of the pipe change. If a section of the pipe cannot be stretched or torqued, the magnetization effects remain unchanged. On this basis, the free point is easily detected by comparing two logging passes, the first pass is recorded with the pipe in a neutral weight condition, and the second logging pass is obtained after the pipe is momentarily stretched or torqued. In near-vertical wells, traditional e-line gravity deployment is used. In highly deviated or horizontal wells, either pump down or tractor conveyance can be used.

This new logging tool provides significant advantages from a safety standpoint; the application of pipe stretch is used for only a few minutes between logging passes. Legacy methods required numerous station measurements with the pipe being stretched. These station measurements consume rig time and can create possible HSE events because the pipe must be pulled/stretched or torqued above the neutral weight condition at each stationary measurement point. Also, because the determination of a free point with this new tool utilizes a comparison of two logging passes, real-time operations with continuous satellite communications readily enables the involvement of remotely-based pipe recovery experts with the pipe recovery planning and execution for freeing the pipe. The new technology is independent of a highly skilled on-site pipe recovery expert and the delays associated with waiting for the expert to arrive on location.

The tool is small in diameter and is run centralized; it does not require the addition of weight bars for slip engagement. These features shorten the length of the tool string and simplify e-line rig up procedures. The short tool length provides advantages in deviated and horizontal well conditions in which pump down free point tool deployment may be required.

The tool design incorporates safe electronic circuitry which enables explosive devices, such as string shots or other pipe recovery explosive devices, to be run in combination with the Halliburton Free Point Tool on a single e-line deployment. This safe combination of free point determination and pipe recovery on a single logging tool trip greatly reduces nonproductive time by eliminating the time required to trip out with the free point tool, pick up and run in the hole with the string shot, and perform depth tie-in.