| ticle describes the three different techniques used in | | | | for the environment. It's a very positive scenario." |
| enhanced oil recovery (EOR) one of the growing | | | | EOR Technique: Thermal Recovery |
| trends in oil and gas exploration and drilling. | | | | Thermal recovery accounts for the other half of |
| EOR Technique: Gas Injection | | | | EOR production in the United States. The thermal |
| The most popular and growing EOR technique , | | | | recovery technique is primarily utilized in the oil fields |
| accounting for 50% of EOR production in the United | | | | of California. Essentially, thermal recovery uses heat |
| States, involves gas injection. Gas injection has | | | | to improve oil flow rates. Steam will be injected into |
| proven to be the most consistently successful | | | | the reservoir to lower the viscosity of heavy viscous |
| technique for increasing oil production in various types | | | | oil, allowing the oil to more easily flow through and be |
| of oil reservoirs. Many major oil companies have | | | | extracted. Dolberry Oil estimates that steam |
| taken advantage of the gas injection technique since | | | | accounts for 52% of the market methods utilized for |
| it was first attempted in Surry County, Texas in the | | | | EOR. In comparison with gas injection, carbon dioxide |
| 1970s. | | | | is at 31% and nitrogen is at 17%. |
| The ultimate goal of gas injection is to restore | | | | Gary Dolberry and Dolberry Oil and Gas actually have |
| reservoir pressure , increase oil production, and lower | | | | access to a proprietary steam injection thermal |
| operating costs. One reason that this method of EOR | | | | recovery technology that most oil production |
| has not seen more widespread application is the high | | | | management companies do not. The technology is |
| upfront investment costs for the requisite equipment | | | | commonly referred to as "steam slugging" and |
| and gas components. While gas injection can result in | | | | involves a mixture of carbon dioxide and steam that |
| lower operating costs, this high initial fixed cost was | | | | results in roughly twice the recovery efficiency of |
| the barrier to entry into gas injection EOR for many | | | | hydrocarbons in two-thirds the elapsed time. Steam |
| smaller independent oil companies. As previously | | | | slugging has typically produced results in the range of |
| mentioned, the investment return made possible by | | | | ten additional barrels per day, and also provides |
| rising oil prices has led the way for even smaller | | | | added benefits like well bore cleaning and water |
| independent oil companies to get into the game as | | | | disposal. |
| well. | | | | A strategy that is commonly utilized by companies |
| Gas injection involves carbon dioxide, nitrogen, or | | | | who have access to steam slugging is what is called |
| natural gas being injected into a reservoir. Once | | | | a "Huff and Puff" scenario. In this scenario, each well |
| injected, the gas expands and compels additional oil | | | | is subjected to 8-12 hours of injection - the "Huff." |
| into a production wellbore where it can be extracted. | | | | The well then undergoes a 12-15 hour "Soak" period |
| The gas will subsequently dissolve into the oil and | | | | in which carbon dioxide mixes with the crude oil while |
| both lower the viscosity of the oil and improve the | | | | nitrogen pull the oil to the lowest pressure area. |
| oil's flow rate. In many applications of gas injection, | | | | Steam then provides additional pressure that |
| up to two-thirds of the injected carbon dioxide will | | | | produces greater oil production as the additional heat |
| return with the oil that is produced. Re-injecting the | | | | assists in loosening the crude oil in the "pay zone" |
| recycled carbon dioxide to release additional oil will | | | | surrounding the well. Finally , during "Puff" cycle, the |
| then minimize operating costs. | | | | well bore and surrounding pay zone fill with fluid that |
| Communities such as Midwest, Wyoming, are also | | | | will be produced or recovered. |
| experiencing ancillary benefits from gas injection EOR | | | | EOR Technique: Chemical Recovery |
| performed by companies like Anadarko Petroleum. | | | | Another technique that is utilized in less than one |
| The utilization of gas injection EOR cleared the | | | | percent of all EOR efforts is chemical injection, in |
| landscape of many unsightly power poles, | | | | which long-chained molecules called polymers are used |
| conventional pumping wells, and power lines. Plus, | | | | to increase the effectiveness of water floods. Water |
| tons of greenhouse gases were prevented from | | | | flooding is a widely utilized secondary EOR technique |
| polluting the atmosphere . As Anadarko spokesman | | | | used to increase overall field output while achieving |
| Rick Robitaille told the Casper Star-Tribune, "It's good | | | | higher oil to water ratios. |
| for the economy. It's good for the country. It's good | | | | |