Advance in free-point determination saves operator $500,000

Overview 

A deepwater operator working in the Gulf of Mexico encountered stuck pipe that stalled operations. A competitor already on site deployed a strain-gauge free-point tool to identify where the pipe was stuck so it could be effectively recovered. But after 18 hours of unsuccessful attempts to locate the free point, the operator turned to Halliburton for a more advanced solution. That solution turned out to be the Halliburton Free-Point Tool (HFPT). It quickly and accurately identifies the free point by measuring changes in the magnetic properties of the pipe. A Halliburton engineer deployed the HFPT on the competitor’s wireline. Within 45 minutes of reaching bottom, the HFPT positively identified the free point and accomplished in just 7.5 hours what the competitor’s tool could not achieve in 18 hours. This saved the operator at least 10.5 hours of NPT, valued at approximately $500,000.

Challenge

When faced with stuck pipe, the operator needed a fast and accurate way to locate the free point before pipe recovery operations could begin. After the operator struggled with a strain-gauge tool for 18 hours with no conclusive results, they turned to a faster, more advanced technology. 

Strain-gauge tools have exposed and moving parts that can cause false readings, malfunctions and miscalibrations. A strain-gauge tool doesn’t function well in pipe with changing internal diameters. It also requires multiple stops to stress the pipe, exposing personnel to increased HSE risk.

The operator began the job using a competitor’s wireline equipment. When the competitor’s strain-gauge tool failed to deliver accurate results, the operator needed a better solution that had to work on the same competitor’s wireline. There wasn’t enough time to bring out a new wireline unit.

Solution

 Halliburton’s HFPT technology eliminates the trial-and-error method used by strain-gauge tools. It relies on altered magnetic properties of the pipe to accurately locate the free point in one run. In this case, the operator successfully located the free point within 45 minutes of reaching bottom.

 The HFPT is a slick cylindrical tool with no anchors or protrusions to cause problems downhole. It collects all the data it needs in real time on a single trip during which the pipe is stretched only once. This greatly reduces HSE risk.

 The HFPT is completely conveyance independent. It can work on any service company’s e-line equipment without compatibility issues. The operator previously qualified the HFPT for use in the field, so when the pipe stuck, they had confidence the tool would work successfully

Result

 Unlike a strain-gauge tool, the HFPT measures changes in the magnetic properties of the pipe to determine a free point. It is the only technology of its type in the industry. While traveling downhole, the HFPT records the magnetic properties of the pipe and creates a baseline log curve. The pipe is stretched or torqued and set back to neutral weight. Then the HFPT travels uphole and records the changed magnetic properties of the pipe to create a second log curve. The pipe’s magnetic properties will change after being stressed. The two log curves compare the pipe’s magnetic properties before and after stress. The point where log curves overlay indicates the stuck point. Where they separate indicates free pipe or partially free pipe. This makes log interpretation simple and completely eliminates the need for the trial-and-error system of the strain-gauge free-point tool. 

Strain-gauge tools have bow-spring anchors that can slip and do not work well in pipe where the internal diameter changes, further complicating operations. But the HFPT features a slick, cylindrical design that works well in pipe of different diameters – without a strain gauge or anchors. It also eliminates the need for multiple stops to stress the pipe. Less rig time is spent working the pipe because, with the HFPT, pipe is only stressed once. This greatly minimizes HSE risk by reducing exposure to rig-floor hazards and improves safety for the entire rig crew. 

 If the operator had not called Halliburton, the next step would have been to mobilize a second strain gauge and crew, causing additional delays and costs with no guarantee of success. The operator estimates the HFPT saved at least 10.5 hours of rig time worth $500,000. If the operator had run the HFPT to begin with, the savings would have been even greater