Analogous GeologyEurope contains many underexplored basins with analogous pressure regimes, burial history, tectonic processes, and depositional patterns to North American shale plays.

By collaborating with North America’s leading shale gas technology company and their international network, Realm can rapidly transfer and modify best practices from all major North American shale plays to continental Europe and beyond, regardless of geologic or geographic differences.

Horizontal Drilling & Multi Stage FracturingHorizontal drilling and hydraulic multi-stage fracture stimulation are the most significant break throughs in natural gas extraction technology and are key to the success of increasing the volume of gas produced and recovered. 

The process involves mounting a drill bit on the end of a drill pipe. As the bit grinds away, a mixture of water and additives, called mud, is pumped into the hole to cool the bit and flush the cuttings to the surface. The mud also cakes on the walls of the well bore, keeping it in tact. Similar to a vertical well, the hole is drilled to just under the deepest fresh water near the surface. The drill pipe and bit are then removed. 

Surface casing is inserted into the drilled hole to isolate the fresh water zone and also serves as a foundation for the blow out preventer; a safety device that connects the rig to the well bore. Then, cement is pumped down the casing and out the through the opening of the shoe, at the bottom of the casing. It is then forced up between the casing and the hole, sealing off the well bore from the fresh water. The cementing process prevents contamination of the fresh water aquifers. 

The pipe and bit are lowered back down the hole to drill through the plug and cement and continue the vertical section of the well, to approximately 500 feet above the planned horizontal leg. This depth is called the kick off point, where the curve will begin so the horizontal section can be drilled. Up to this point, the process is the same as drilling a vertical well. Again, the pipe and bit are pulled out of the hole and a downhole drilling motor with “measurement while drilling instruments” (MWD) is lowered back into the hole to begin the angle building process. The distance to make the curve from the kickoff point to where the well bore becomes horizontal is just under a quarter of a mile. Once the curve is completed, drilling begins on the well’s horizontal section, called the lateral. The pipe used to drill the well measures 30 feet in length and weighs approximately 495 pounds each. It takes over 350 pieces of pipe weighing nearly 87 tons to drill a 10,500 foot well. 

At various stages of drilling, the pipe is taken out of the hole for tool and bit changes and put back in. This process is called tripping pipe. When the targeted distance is reached, the drill pipe and bit are removed from the well bore one last time. Production casing is now inserted into the full length of the wellbore.  Cement is again pumped down the casing and out through the hole in the casing shoe, forcing the cement up between the casing and the wall of the hole, filling the open space know as the annulus. 

Casing the well is a very important process because it permanently secures the well bore and it prevents hydrocarbons and other fluids from seeping out into the formation as they are brought to the surface. At this point, the drilling rig is no longer needed. A temporary well head is installed and the location is prepared for the service crew who will perf, frac and prepare the well for production. The first of these steps is to perf, or perforate, the casing. A perforating gun is lowered by wire line into the casing to the targeted section of the horizontal leg. An electrical current is sent down the wire line to the perf gun and sets off a charge that shoots small holes through the casing and cement and out a short distance into the shale formation. The perf gun is then pulled out of the hole.

Next, because the shale is tight or compressed, the well will have to be fracced, known as hydraulic fracturing. This is a process where water, sand and additives are pumped into the wellbore and down the casing under extremely high pressure. As the mixture is forced out through the perforations and into the surrounding rock, the pressure causes the shale to fracture. This creates a fairway connecting the reservoir to the well and allows the released gas to flow to the wellbore. Next, a temporary plug is placed at the heal (or left side) of the first stage frac. The plug closes off, or isolates, the perforated and fracced section of the wellbore so that the second stage section of the horizontal leg can be perforated and fracced. Tight reservoirs do not contain natural fractures and, therefore, cannot be produced economically without hydraulic fracturing. The permeability is increased by providing pathways through which gas can flow more easily. 

Micro Seismic Technology Large volumes of hydrocarbons locked into impermeable reservoirs are characteristic of unconventional natural gas resources. As such, operators rely on advanced technology to continually optimize and improve their production efficiency. As an example, recent technological break throughs have allowed an increase in the number of hydraulic fracturing stimulations within a single horizontal bore hole, which, in turn, has allowed more gas to be produced from a single well.

Micro seismic monitoring enables engineers to detect patterns of fluid movement, fracture development, compaction or faults in a hydraulic fracture. In recent years, the key to substantial technical advances has been the commercial success of monitoring, especially in real time.