Shale gas is natural gas that is tightly locked in very small spaces within the shale rock formation. To unlock it, Nexen uses technology to horizontally drill and stimulate (fracture) the gas-bearing zones. The creation of fractures within the shale releases the gas. Once released, shale gas is produced the same way as conventional natural gas.
Drilling and Fracing Process
Step 1: To begin developing a well, a vertical surface hole is drilled, reaching past the deepest water aquifer, and then protective steel pipe (called casing) is installed, cemented in place, and pressure tested to ensure the integrity of the well and protection of water aquifers.
Step 2: Drilling continues vertically until the well reaches a point (kickoff point) just above the shale formation where the drill bit gradually curves and then enters the shale formation horizontally, where drilling continues.
Step 3: After drilling the total depth of the well, secondary or intermediate casing is installed and cemented through the entire length of the well, including the horizontal section, to ensure well integrity is maintained.
Step 4: A temporary wellhead is installed and the well is prepared for the fracturing process.
Step 5: Small perforations (tiny holes) are created in selected horizontal sections of the well that are in contact with the shale formation.
Step 6: Following all required regulations and guidelines, fracing fluid (made up of approximately 99.5% water and sand) is then pumped into the well at high pressure, creating fractures in the shale formation. Typically in the Horn River Basin, the fracture network extends to 200-250 metres laterally, and 100–150 metres in height.
Processing the Natural Gas
Connecting to surface facilities: Once the fracing is completed, the well is connected by a pipeline to surface facilities.
Distribution: At a central field facility, the natural gas is compressed to allow it to enter a gas gathering pipeline to flow to third-party processing plants. Natural gas is then made available to consumers through distribution pipelines to residential, commercial, and industrial users in North America to heat homes, generate electricity and power vehicles like trucks and buses.
Reclamation: After production is depleted, we reclaim all disturbed areas, and the area is brought back to its original land capability.