Before we can begin to choose a drilling site, we strategically search for gas by using a variety of tools and testing mechanisms. Once we identify optimum locations to extract natural gas, we begin planning our operations and complete numerous environmental permitting requirements. After receiving regulatory approval and completing our planning process, we then begin drilling pad and location construction. Roads and drilling pads are built to allow equipment access and designed to minimize environmental impact from erosion and sedimentation. We may also construct lined water pits in order to store fresh water. We use double-walled and triple-lined above ground tanks to store flowback water from producing wells until this water can be reused in another well completion. Topsoil is kept for site reclamation and allows the restoration of a landowner’s property to its original condition.
Drilling and Completion
PennEnergy contracts drilling and completion operations to qualified and experienced specialists with strict oversight of all activities to ensure the safety of people and protection of the environment.
The drilling and activity includes several phases, all with the net result that the drilling equipment and drill bit breaks through the soil and the earth’s rock, penetrating numerous geological strata until the bit reaches the targeted interval for gas and oil extraction. Typically, the upper vertical section of the well is drilled with compressed air pumped down the drill pipe and bit, travelling back up the outside of the pipe to remove the drilled rock fragments from the wellbore. After the drill bit passes through the deepest fresh water-bearing zone, steel casing is run and set to the bottom of the drilled interval. Cement is then pumped down the steel casing and is circulated back up the annular space between the steel casing and rock to the surface, effectively sealing and protecting the fresh water strata. As the drilling process continues to deeper intervals, smaller diameter steel casing strings are used to protect and seal the lower strata. Each casing string is also followed by a layer of cement pumped between the steel casing and the rock (and the upper casing strings) surrounding it, further protecting the groundwater. The ultimate result is that there are several layers of steel casings and cement protecting the shallow fresh water strata. After the vertical section of the well is drilled, we typically use a second, larger drilling rig to drill the deeper horizontal portion of the well that can extend several thousand feet laterally. The complete process of drilling a horizontal Marcellus well can take upwards of 30 days.
After the well has been drilled to its total depth and length, it is necessary to create openings within the horizontal section of the well so that natural gas can flow from the targeted shale interval through the final casing string and cement into the well bore. One method that is often used to create these openings is by sending a special “perforating” tool downhole with explosive charges that are safely detonated remotely from the surface to create discrete and exact holes into the steel casing and cement.
After the well is drilled and the casing perforated, natural gas may still not travel in economically viable volumes to the surface without creating small pathways into the well borehole deep within the shale. Hydraulic fracturing is the method that has been commonly used to for decades to create those pathways into the geologic formation (Marcellus, Utica, or other) allowing natural gas to be extracted from the well. Modern hydraulic fracturing is a safe, well-developed and highly monitored procedure that is used to complete almost all gas and oil wells in the United States.
Hydraulic fracturing is a process that pumps a mixture of water, sand and very dilute additives, under pressure down the well and into the shale creating small pathways allowing natural gas to move from the rock and into the wellbore. Hydraulic fracturing typically requires several million gallons of water for each horizontal well that is drilled. The use and movement of water for hydraulic fracturing is closely monitored and regulated, and all oil & gas operators must obtain permits from regulatory agencies that require them to protect water supplies and aquatic life.For Additional Information: