Off-balance drilling maintains lower pressure in the well than the oil and gas reservoir, reducing damage to the formation. Dry air drilling is one form of unbalanced drilling, but its effectiveness depends on the specific formation. Despite higher initial costs, unbalanced drilling can be more effective in the long term.
Off-balance drilling, also called pressure controlled drilling, is a form of oil and gas drilling that is a little less common than other forms of drilling. This technique maintains a lower pressure in the drilled well than the pressure exerted by the oil and gas reservoir. When the pressure in the well is lower than the pressure oil and gas can exert, the gas and fluid buildup caused by drilling can be brought to the surface and managed appropriately. Some view unbalanced drilling as a more effective technique, despite its higher initial cost.
Perhaps the most important benefit of such drilling is the reduction of damage to the natural oil and gas formation. In many other drilling techniques, the mud used for drilling and holding well pressure can be forced out of the well and into the reservoir deposit, damaging the well and the overall operation. Off-balance drilling, on the other hand, encourages gas, fluids, and rock material from the borehole to the surface using a variety of methods.
One form of unbalanced drilling is dry air drilling, in which air pressure alone is used to cool the drill bit and encourage the flow of gas, liquid and rock out of the wellborehole. With dry air drilling, only a small amount of oil is needed to lubricate the machinery and maintain optimum drilling conditions as well as air. Other forms of unbalanced drilling might include fog, foam, or stable foam drilling, where varying amounts of a foaming agent are used to gather materials and encourage their flow to the surface, to help maintain proper pressure. Of course, the specific form of off-balance drilling usually depends on the conditions of the specific oil or gas formation.
Despite the many benefits of this type of drilling, many operations prefer unbalanced drilling and other drilling methods. Conditions vary widely across oil and gas formations, so unbalanced drilling may not be effective for all operations. The initial cost can also be higher for this type of drilling, although the long-term benefits, including longer bit life, less tank damage, and handling of materials produced during drilling, could offset the cost. With proper planning, including intense pre-planning procedures and on-site engineers ready to handle drilling problems, unbalanced drilling can be more effective than many other forms of oil and gas drilling.
Protect your devices with Threat Protection by NordVPN
