It takes about six weeks to drill, hydraulically fracture and complete a typical well, but the work begins long before a well is ever “spud,” and a producing well will continue working for North Dakota much longer thereafter. Read more about how the process works, from the initial lease to production to the plugging and reclamation of a well.
Before a well can be drilled, landmen must acquire a lease from mineral owners. The leasing process creates a legal agreement between the oil producer and the holder or holders of the mineral rights, which may be divided up among multiple people. The lease spells out the rights and responsibilities of all parties to the agreement, and specifies the payments that are to be made to the lessee.
In cases where the holder of the mineral rights does not own the surface land, the oil producer negotiates a Surface Use Agreement (SUA) with the landowner. The SUA typically spells out the location of the well pad, the amount of surface that will be used, easements, access to the location, and the rights and responsibilities of each party. Information about SUAs can be found in Chapter 38 of the North Dakota Century Code.
Locate a well
The Industrial Commission establishes drilling units and legal locations for wells. Although not always the case, the most common spacing units for horizontal wells are either 640-acre spacing units (or one mile by one mile) or 1280-acre spacing units (two miles by one mile). Advances in horizontal drilling allow the entire spacing unit to be developed from just one well pad, reducing impact to the surface. Up to 14 wells may be placed on a single well pad.
Horizontal drilling also allows for the development of energy corridors, which helps keep most of the oilfield traffic and impacts to one corridor every four miles. This also means that the four square miles in between each corridor is not impacted, allowing for continued use for agriculture, ranching, habitat, recreation or other development.
Once the well has been located, applications containing the proposed well construction are submitted to the Industrial Commission for permits to drill.
The first step of drilling a well is to prepare the land on which the well pad is to be located. Existing access roads to the site are used whenever possible. If an access road needs to be created, the road will take the shortest route that’s feasible to minimize the disturbance to the land. While the size of the land area needed for the well will vary depending on various conditions, average area needed for a typical well in the Bakken is usually about four to six acres during the drilling phase. For multiple wells on the same pad, approximately seven acres are usually needed. Once the well is in production, the area needed is usually reduced by about 25 percent.
Every wellsite must meet stringent environmental regulations that protect the surrounding land, water, air quality and wildlife. Topsoil is removed and stockpiled for future reclamation once the well stops producing and is plugged. Sites are built with multiple levels of protection, including liners, casing, cementing, protection mats, trenches, containment units, earthen berms, and blow-out preventers. Multiple wells on one site reduce the overall footprint. Infrastructure improvements, such as expanding pipeline and rail capacity and access, will also lessen the environmental impact.
Drilling a Well
A rig that can drill a 10,000 foot well typically requires 50 to 75 people to move and assemble. To prevent contamination of soil or water during the drilling, a pit is dug and lined with a thick layer of plastic. A pilot hole is dug for the well’s main hole. Two other holes are also dug to hold equipment and pipe during drilling. It usually takes three to four days to assemble a rig, which is then inspected before the drilling process begins.
Drilling occurs in stages: drilling, running and cementing new casing. There are five layers of cement and casing in a typical Bakken well to help protect groundwater from the drilling process. Once the casing and cementing is finished, the well is drilled to the target zone. Each bit usually lasts for 4500 to 6500 feet of drilling. Derrick hands circulate drilling fluid, called “mud,” through the hole to cool the bit. When the hole is at its designated depth, fluid is circulated through the hole to log information to determine if this well has the capacity to produce oil. If it’s designated as a producer, the casing is tested again, the drill pipe is removed, and the last string of production casing is inserted. The casing is cemented in the hole and the rig is prepared for production.
Well Completion and Hydraulic Fracturing
Once a well has been drilled, the next step is well completion or hydraulic fracturing, often called “fracking.” This technology allows engineers to extract oil and natural gas that isn’t recoverable with other methods.
Due to the unique geology of the Bakken, it’s usually necessary to fracture the well. Fracturing involves pumping a mixture of mostly water and sand into the oil to develop fractures, or pathways for the petroleum to flow out of the reservoir rock. The fracking fluid is about 90 percent water, 9.5 percent sand, and one-half of one percent chemicals that prevent corrosion and increase viscosity, allowing the mixture to flow freely. The precise mixture of the fluid and the time it takes to frack a well depend upon the specific composition and characteristics of each well site. A list of commonly used chemicals can be found at EnergyInDepth.org. The exact composition of the fluid will vary, based on the geology of each individual site.
While hydraulic fracturing has recently become a topic of contention, this process has been used on over one million wells in the U.S. over the past 60 years. Many years of experience have contributed to today’s high level of expertise in fracking, with proven standards, procedures and regulations in place to protect workers and the environment.
For more information on hydraulic fracturing and to view the chemical disclosure registry, visit www.fracfocus.com.
Once a well is drilled and completed, it will begin producing oil. After initial production, a well will usually need artificial lift to continue producing, such as the pumping unit shown to the left.
Most wells drilled today will continue producing for 45 years or more. That’s a very brief timeframe of construction work for a long-term investment in energy production.
Plugging & Reclamation
Once a well has stopped producing at a sufficient rate to be economical, the casing is sealed with cement, and the casing is cut off three to six feet below ground. The top soil is returned to the site and the land is restored to its pre-well construction condition. Only when the landowner and North Dakota Oil and Gas Division are pleased with the result is the operator released from his bond.
Next Steps: In-Fill Drilling and Multiple Wells
From approximately 2006 to 2012, the industry was in the “exploration phase,” which mean companies were working quickly to get at least one producing well on each lease in order to hold that lease. Today, the industry is in the development, or “harvest” phase, where they return to their productive leases and drill multiple “in-fill” wells from a single pad. The North Dakota Department of Mineral Resources estimates that it will take another 15 to 17 years to fully develop the Bakken with today’s technology and each of those wells will continue producing for 45 or more years.