TBL reduces the risk and the cost of evaluating oil and gas wells using wireline-style logging tools. In this new system Reeves wireless Compact tools are run inside drill pipe and into open hole through a drill bit, and logs are taken while tripping the drill string over the interval of interest.
This saves wireline logging time as well as post wireline logging hole conditioning. In addition to saving time, the tools are guaranteed to get past any bad hole conditions that may exist higher up the well.
The system comprises a drill bit with an insert that can be removed from the bit, a latching mechanism for selectively removing the insert from the bit, and a running tool that interacts with the latch to enable the insert and logging string to move out of the bit. The running tool is connected to the lower end of the logging string. The logging tool is hung off in the bit by way of a hang-off tool, with ports to allow circulation while the logging tool is in place.
After an interval has been drilled, the drill pipe is pulled off bottom for a distance equal to the length of the logging string. The tool string and running tool are lowered on a slickline to engage the latch, taking the bit insert into open hole. Formation evaluation data is gathered as the drill pipe is then moved uphole. After logging the interval of interest, the tool string is retrieved on slickline, causing the insert to re-latch in the bit so that drilling or well conditioning is able to re-commence immediately.
The Reeves Compact tools are operated without a wireline, with power coming from batteries and data being recorded to memory. This allows rapid deployment and eliminates a costly conventional surface logging unit. Although the tools are small (2¼-inches diameter), they are designed to operate in hole sizes up to about 12-1/4 inches diameter. Their small size (about half the diameter of conventional tools) also makes them easier to transport, and improves operational efficiency.
Reeves has been working with Shell and industry partners for three years to develop and test the system. Weatherford BBL has supplied bits, and Pioneer Oil Tool Ltd has supplied the running tool.
An 8-1/2 inch PDC bit was initially evaluated in Shell's Drilling and Well Technology facility at Rijswijk in the Netherlands, where a performance advantage was measured relative to the un-modified bit. Latching trials were conducted at Reeves' R&D facility in East Leake, UK, and at the Downhole Technology Centre, Aberdeen. The full system was successfully demonstrated in an exploration well drilled by NAM in the Netherlands. TBL versions of 6-inch and 12-1/4 inch PDC bits have been subsequently developed.
TBL is one of several innovative logging technologies being developed jointly by Reeves and Shell.
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