A wellbore is drilled to aid in the exploration and recovery of natural resources. This wellbore allows hydraulic fracturing fluids to travel down the well while natural gas  flows back up the well. To ensure natural gas exploration is done in an environmentally friendly way, wellbores are constructed in a very meticulous manner. They are made with multiple layers of thick industrial grade steel pipe casings and cement sheaths. Due to their great significance, wellbore construction is highly regulated.
The depths and number of the casings for each wellbore fluctuate depending on the well and rock formations in the area. Wellbores are specifically designed for the requirements of each formation which is why there isn’t a “cookie cutter” wellbore construction.
Typically, there are four casings used on a regular basis:
The outermost layer is known as the Conductor Casing. It is placed into the surface hole and cemented. This layer is used as a barrier to keep surface sediments and water away from the frac’ing procedures, it also helps to stabilize the sides of the hole.
Next is the Surface Casing. This casing is cemented into place from bottom to top and it completely cuts off the well from all surrounding water aquifers.
Then, the Intermediate Casing, this is used for added stability and security. It separates the well from pressured rock formations that could potentially compromise the well’s production.
Finally, there is the Production Casing, this is the innermost layer. It is made to contain all of the frac fluid that is forced down the well in addition to all of the natural gas that flows up as a product. This casing is the longest, it reaches the bottom of the well and it is completely surrounded by cement.
Cabot’s operators use a rotating cement head to rotate each string of casing as cement is being pumped in. This step is necessary so that the cement goes completely around the whole circumference of the steel pipe.
Proper wellbore construction is critical to protecting groundwater, and we take great care to ensure the integrity of the wellbore

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Kelly Grago was born and raised in the quaint town of Sewickley, Pennsylvania. She is a recent graduate of Robert Morris University where she earned a B.A. in Communications with a concentration in Public Relations. Kelly currently works as an Intern in External Affairs for Cabot Oil & Gas Corporation where her responsibilities include writing for Cabot’s social media, scheduling content and event planning.