Casing Wear Series – 3: Prevention

Computer casing wear modeling reduces risks and can identify potential problems prior to its occurring. Necessary modifications on casing designs and drilling parameters could be made before the pumping starts once we can predict the location and magnitude of wear.

Figure 1 shows the 3D visualization of magnitude and location of wear in a previously set casing.

Figure 1. 3D Visualization of Casing Wear
Figure 1. 3D Visualization of Casing Wear

The knowledge we have acquired through decades of studies, lab testing, post-job analyses and computer modeling provides a good foundation for the following casing wear preventive measures:

  • Minimize dogleg severity and expect real dogleg at least 1.5 times higher than the planned value.
  • Use casing friendly tool joint materials.
  • Reduce rotor speed and use downhole motor.
  • Increase ROP.
  • Select proper mud type and add lubricants to reduce wear and friction.
  • Use drill pipe protectors.
  • Use thick wall casing in the anticipated wear section area.
  • Use software to reduce risks.

Please go to to download the complete Casing Wear white paper.

Drilling Software: See the Invisible

We just had a T-Shirt design contest. Graphic designers were asked to put drilling software in perspective of the design.

Nowadays, drilling engineering software is an indispensable tool for drilling engineers. Directional and extended reach drilling and HTHP wells challenge us with more and more technical difficulties. Software is one of the solutions to these problems. However, because of its abstract nature, it is not easy to illustrate drilling software in a T-shirt design. At least, it is difficult to have a good design without using abused images of drilling rigs and computers.

One of the submissions is a pair of glasses as shown below.

See the Invisible | Pegasus Vertex, Inc. - Drilling Software

As soon as we saw it, we liked it. It has a subtle message: our drilling software allows engineers to see the downhole condition, which is invisible to normal eyes.

Oil and gas well is created by drilling a hole of 5 to 50 inches in diameter into the earth with a drilling rig that rotates a drill string with a bit attached. During drilling process, engineers and drillers heavily rely on the limited information on the rig floor to determine the downhole condition, because they cannot see the subsurface.

Typically, only one tenth of iceberg is above water. Majority of iceberg is below water, making it difficult to determine its shape and size. Similar situation exists on the rig floor. Drilling engineers only have handful observations such as hookload, surface torque, pump pressure, ROP, RPM, etc. They can neither see what happens to drill string or formation nor accurately measure the buckling of the pipe. It is like a situation that we walk cross a muddy river: we cannot see the river bed, but our feet do their best sensing the water, mud and rock and send a message to our brains. Drilling operation is a dialog between drillers and formation in the dark. Drilling software turns on light to let engineers see the invisible.

Drilling Software Solves Puzzle

I once attended a Bible study, which focused on the book of Genesis. The teacher asked: “What is the most important piece of jigsaw puzzle?”  Students started to answer “The corner ones”, “One with straight edge”. After a pause, he slowly revealed “The most important piece of jigsaw is the box top.” We all smiled when he showed us a slide of a box of puzzle with puzzle image.

He further explained that the book of Genesis is the box top of the Bible. “Genesis maps out all the happenings of the entire Bible.” He said.

Many of us played with puzzles ourselves or with our children. The finished artwork bears no resemblance to the hundreds of pieces of colored cardboards in the box that initially greeted us. Although the individual elements remain the same, and do not reveal much information, the complete work allows us to see the whole picture.

In a similar manner, drilling engineers are constantly putting together the pieces of procedure, equipment, instrument readings from rig floor, and their own calculations. Our job is to fit them into the right places. This way, we can understand why certain drilling parameters change, why problems occur or what our observation mean.

The beauty of drilling software such as TADPRO (torque and drag) is its ability to put pieces of information including ROP, RPM and WOB all together to solve the puzzle. The integration of operation parameters, wellbore trajectory and advanced mathematics model produces more meaningful results.  Think of TADPRO as your box top!