Adam Ferrari, CEO of Ferrari Energy Answers: What is the Difference Between Drilling and Fracing?
Over the last ten years, numerous credible news outlets have shown an image of a drilling rig and referred to said piece of equipment as a fracing rig. Let me be very clear — there is simply no such piece of equipment called a fracing rig.
Fracing or Drilling?
The journey into oil and gas development starts with a prospect that geoscience professionals believe contains economic volumes of oil and natural gas. A prospect is simply an area of land. To determine whether or not the prospect contains oil and gas, a well must be drilled. The sequence of events then goes something like this:
- A permit to drill is obtained from the regulatory authority in the state where the prospect is located.
- A drilling location is constructed, and a drilling rig is moved onto this location and assembled by experienced construction professionals.
- The drilling rig drills a hole to depth. This hole is typically less than 8 inches in diameter. This hole is then typically cased with steel pipe and cemented in place.
- The large drilling rig is then moved, and the frac crew then moves onto the location.
- Once the fracing is completed and the remaining construction is finished, the wellbore can produce oil and natural gas.
While this outline is simplistic, it is worth noting that drilling and fracing are two distinctly unique steps in oil and gas development. They cannot happen simultaneously, and there is no such thing as a fracing rig. Please take note of my recent article on fracing.
What is Drilling?
Drilling in oil and gas development is the process of putting a relatively small hole in the ground and securing that hole with a steel pipe surrounded by cement. The drilling rig that completes this step has lots of associated equipment to complete this process efficiently. The rig itself has a derrick (a large structure that could be upwards of 100 ft tall), a drill pipe with a bit on the end of the pipe, and a top drive. The derrick supports the weight of the drill string (drill pipe plus bottom hole equipment), and the top drive spins the drill string and the bit and drills through the material to “make hole.” The rig also has a pump that is circulating fluid as a hole is made in order to lift the cuttings out of the wellbore as drilling progresses. The fluid is pumped down the drill pipe and rises up the annular space between the hole and drill pipe, lifting the cuttings from the wellbore. This process can be as quick as three days or take up to a month or more, depending on how deep the wellbore is.
What is Fracing?
Once the drilling rig is finished drilling the well and the hole is secured with casing and cement, the completion process can begin. Completions is a broad term to describe all of the activities that happen once a well is drilled. The most significant step in the completions process is the fracing process, but some critical steps must occur before fracing. The first step in the completions process is to perforate the casing. This is done by using a perforating gun on the end of a wireline tool string. The string is run to depth, and a technician in the control truck activates the charges when the tool is at depth. Typically, there are anywhere from 10 to 30 half-inch charges fired off during each frac stage. Now the frac crew is ready to pump the first stage of the frac job. Fracing is simply the process of pumping water carrying beach sand into the oil-bearing rocks through the holes just created by perforating. After the correct volume has been pumped per the engineer in charge, it is time to move on to stage 2. More perforating holes must be shot into the casing uphole from stage 1, and a composite plug must be set in order to provide a barrier between stage one and stage 2. This plug is set on the same tool string that perforates the casing for stage 2. This process is repeated over and over until all of the stages have been fraced. Modern horizontal wellbores are up to 2 miles in length and typically completed with 50 stages of fracing. The first stage is often referred to as the toe, and the last stage is the heel of the wellbore.
Fracing and Drilling are Both Vital Steps in Oil and Gas Extraction, But They Are Not the Same.
After reading this article, you will now be able to spot inaccurate reporting on the subject of fracing and drilling, and next time you see an image of a fracing rig, you will know that it is just a drilling rig. You cannot frac a well that is not yet drilled, so think of it like a relay race with drilling leading the way and fracing taking it across the finish line.
About Adam Ferrari
Adam Ferrari is the founder of the mineral acquisitions company Ferrari Energy. He is a chemical engineer by degree and is an accomplished petroleum engineer by profession. He also has experience in the financial sector through his work at an investment banking firm. Under his leadership, his company has supported numerous charitable organizations, including St. Jude Children’s Hospital, Freedom Service Dogs, Denver Rescue Mission, Coats for Colorado, and Next Steps of Chicago.
