In part one of this multi-part blog series, we went over some of the basics for tubing anchors within oil drilling components. Also referred to as tubing anchor catchers (TACs), these products are vital for achieving efficient pumping operation through maintaining tension during pumping and preventing pipe from falling into the well.
At Oilfield Equipment & Manufacturing, we’re proud to offer a variety of drilling rig components, including tubing anchor products built using our Baker style. In today’s part two, we’ll go over a couple very important areas to consider when purchasing and installing tubing anchors as part of your oil drilling setup – some basics on the wellhead you use and the role this plays, plus some simple tips we can offer on installation of tubing anchor catchers.
A big factor we’ll dig into later in this series when it comes to tubing anchors is stretch, and the wellhead you choose plays a major role here. Generally speaking, there are two types of wellheads you might be choosing from: Screw format or slip format. Some basics on each:
- Screw format: For this wellhead, the tubing will be screwed into the bottom of the flange. This requires overstretching of the tube to at least 18 inches, allowing for installation of pulling unit slips under the top tubing collar. If the tubing is not properly stretched, there, may be slack in the tubing string that creates issues during operation.
- Slip format: Tubing here will be stretched, allowing the tapered slips to catch the tubing spring during operation. These slips have teeth, which offer friction and keep the string stretched and straight. This setup must be done with straightness in mind – crooked application will cause only part of the slips to contact the tubing, which will stress the tube and often result in failure at the contact point.
Our pros will be happy to answer any questions you have about wellhead choice and how this impacts your overall setup.
Here are some general tips on installing tubing anchor catchers within your oil drilling rig:
- The anchor should be placed immediately below the pump, with the seating nipple screwed into the top sub of the anchor (in cases where the pump must be below the TAC, there will be some specific factors on anchor and tensile strength to consider).
- Drag springs must get special attention – they hold the cage stationary while upper and lower cones can expand. Drag springs also guide the anchor through the casing. For this reason, drag springs should never be used as a handle for carrying or tailing – this might bend the springs and limit their function.
- One more note on drag springs: If your installation is at a particularly deep depth (below 8,000 feet), two or more drag springs should be utilized on top of each other.
- A general installation note: Tubing anchors should not be used in any well with bad casings, which can cause problems with sand or scale buildup. The casing must be redressed first in such cases.
For more on tubing anchor installation or wellhead considerations, or to learn about any of our oil rig components, speak to the staff at Oilfield Equipment & Manufacturing today.