Sunday, November 11, 2007

Stimulation Techniques used in Oil Drilling

Fictional media depictions of oil drilling have given the general public an inaccurate picture of the ease with which oil is removed from its rocky reservoirs. Typically it is not all gushing geysers in response to a little drilling. In actuality an oil-bearing formation may contain a large amount of oil, but low flow rate as a result of low permeability or blockage from debris may slow the extraction process. This is especially true for tight sands, oil shale, and coal bed methane. There are two major categories of stimulation techniques used by oil drillers to help alleviate this problem and restore flow of fluids from the reservoir to the borehole. They are called hydraulic fracturing, and acidizing or matrix treatments.

Hydraulic fracturing is a method that creates new pathways for the oil to travel by injecting fluid underground at high pressures. This causes the formations to fracture, and the oil or gas flows more freely out of the formation .Typically, in order to create fractures a mixture of water, proppants (sand or ceramic beads) and chemicals is pumped into the rock or coal formation. Eventually, the formation will not be able to absorb the fluid at the same rate that it is being injected. At this point, the pressure created causes the formation to crack or fracture. The fractures are held open by the proppants, and the oil or gas is then able to flow through the fractures to the well. Coal bed fracture treatments use between 50,000 and 350,000 gallons of various stimulation and fracturing fluids, and anywhere from 75,000 to 320,000 pounds of proppant during the hydraulic fracturing of a single well.

Chemicals commonly used in combination with stimulant fuels include diesel fuel, which contains benzene, ethylbenzene, toluene, xylene, naphthalene, polycyclic aromatic hydrocarbons, methanol, formaldehyde, ethylene glycol, glycol ethers, and sodium hydroxide. This fracturing method is performed above the fracture pressure of the formation and creates a highly passable flow path between the reservoir and the borehole.

Acidizing involves injecting the formation with acid, typically hydrochloric acid, which causes the rock to dissolve opening rock pores and allowing fluid to flow more easily. Matrix acidizing is administered at a high rate, but at treatment pressures below the fracture pressure of the formation. This allows the acid to saturate the formation and amplify the depth of treatment while averting further breakdown of the reservoir formation. These methods are sometimes combined to create an acid fracture treatment.
These important techniques are helping companies like Triple Diamond Energy Corporation to get the maximum benefit out of their wells, by reducing costs and environmental impact of oil and gas drilling.

Chris Jent is the chief marketing officer of Triple Diamond Energy Corp. Triple Diamond Energy specializes in acquiring the highest quality prime oil and gas properties. For more information, visit http://www.triplediamondenergycorp.blogspot.com.

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