More and more, we are hearing about remarkable strides the United States is making toward energy independence, a national goal that has proven elusive. The U.S. is also achieving remarkable reductions in its carbon output. According to the Energy Information Administration, carbon emissions in this country are at their lowest levels since 1994.
There are many reasons for the progress toward energy self-sufficiency, just as there are many reasons for the reduction of our carbon footprint.
Certainly, technology advancements and improved production techniques have something to do with it. In no area is this fact more clear than domestic onshore oil development and production.
The technologies and techniques used in today’s oilfield depend upon the specific characteristics of the particular resource being developed or produced. Just as a bridge or skyscraper is designed and built taking into account site-specific conditions, so too are oil wells designed, constructed, and operated.
It is resource characteristics, such as oil saturation, depositional depth and thickness, rock density, and permeability, that caused hydraulic fracturing to be used over one million times since 1947. And hydraulic fracturing is helping make energy independence attainable; however, it is used more in North Dakota than California.
In California, over 100,000 wells have been steamed since the 1950s; steaming is a practice used more extensively here than other states. The use of cyclic steam techniques is another reason more and more U.S. energy needs are being met with domestically produced oil.
Cyclic steaming and hydraulic fracturing have very little in common except both have become safer and more effective over time, and both have found new applications since they were first used.
For example, cyclic steaming was first used in the 1990s to successfully produce oil from diatomite deposits in California. Diatomite is the accumulated skeletal remains of diatoms, single-celled marine organisms that died millions of years ago and sank to the bottom of the ancient sea they inhabited. Some, but not all, diatomite became filled with oil. However, oil found in diatomite tends to lack mobility, i.e., the ability to flow freely. The lack of mobility is overcome, in part, with heat from steam. The oil becomes more mobile and flows more easily, just as syrup does when heated.
Prior to the use of cyclic steam practices, oil production from diatomite was next to zero. It now accounts for 50,000 to 100,000 barrels of oil per day or between 10 percent and 20 percent of California’s total daily production.
Diatomite production in Santa Barbara County uses a carefully controlled and closely monitored three-step process: inject, soak, and produce. Steam is introduced into and oil is produced from the same well in repetitive fashion, hence the name: cyclic steaming.
Although commonly known, it is worth repeating, all oil development and production activities in California are extensively regulated. The Division of Oil, Gas and Geothermal Resources (DOGGR) oversees all aspects of oil production activities that occur below the surface. This makes DOGGR one of the key regulatory agencies overseeing cyclic steam operations.
DOGGR places limits on the pressure at which steam can be introduced to diatomite. The lower pressure used in cyclic steam operations is one of many differences that distinguish it entirely from hydraulic fracturing. The specific pressure limitations vary from location to location because resource characteristics vary from location to location.
As steam is introduced to the diatomite, it condenses back to water. The diatomite imbibes the water, and as it does, oil is expelled. Pressure limitations guard against steam unexpectedly finding its way to the surface, bringing with it oil to places it does not belong.
Of course, in Santa Barbara County, naturally occurring seeps routinely discharge oil. In some areas, natural seeps and cyclic steaming operations coexist, and there is often confusion about which came first. Without exception, seeps predate steaming operations, by hundreds, and perhaps thousands, of years.
DOGGR also closely regulates the design and construction of all wells in the state, including those in cyclic steam operations.
Just as a highway is a corridor upon which cars assemble and travel from one point to another, a well is a conduit into which oil migrates and through which it is produced to the surface. A well is constructed of multiple layers of steel and cement designed to ensure mechanical integrity, safety, and reliability.
The specific number of redundant protective layers and the specification of materials used depend upon many factors, including but not limited to the area geology, the depth of the well, and project operating parameters.
A successful cyclic steam operation requires heat. Heat is integral for success. At the same time, it also establishes operational boundaries.
Heat can travel only so far before it cools; in diatomite, it can penetrate a distance slightly greater than one hundred feet from the well. The distance it penetrates defines the area from which oil is produced. The limited distance heat can travel reduces greatly, if not eliminates, the possible impacts upon immediate neighbors.
To make steam, water must be heated, and as you would expect, the equipment used to do this is called a steam generator. Similar to any airplane, boat, bus, car, tractor, or truck powered by an internal combustion engine, a steam generator emits carbon through its exhaust. But as with every other aspect of a cyclic steam operation, these carbon emissions are regulated, albeit not by DOGGR; carbon emissions are regulated by the California Air Resources Board (CARB).
CARB regulates oil and gas industry emissions because the oil and gas industry is specifically subject to the California Global Warming Solutions Act of 2006. Also known as AB32, the law imposes strict limits on carbon emissions; limits that will become more stringent over time.
AB32 is part of the reason the U.S. carbon footprint has fallen to 1994 levels. It is part of the reason the carbon footprint will continue declining in coming years. Increasing oil production is part of the reason the U.S. is moving inexorably toward greater energy independence. Cyclic steaming done safely and responsibly can help achieve these elusive goals.