Author: bomuo

A well that has not encountered hydrocarbons that can be extracted economically and has thus been abandoned

The oil drilling segment covers firms that provide drilling rigs and personnel, plus related equipment and services. Customers include oil and gas producers

A term mostly employed to describe a variety of organizations established to attract venture capital to oil and gas exploration and development

To prevent build-up of solids in the wellbore, hole-cleaning of the wellbore must be achieved by the drilling fluid. In fact, one of the primary functions of the drilling fluid is to carry the “cuttings” from the bit where they are created to the surface of the earth. In vertical or near vertical wells, the drilling fluid is normally formulated to have viscosity high enough to decrease the settling velocity of cuttings to a value much less than the upward velocity of drilling fluid in the hole, so the cuttings will be efficiently carried from the wellbore. Drilling mud is the fluid which is pumped into the well when it is being drilled in order to lubricate, control pressure and remove cuttings. It is a special mixture of clay, water, or refined oil, and chemical additives pumped downhole through the drill pipe and drill bit. The mud cools the rapidly rotating bit, lubricates the drill pipe as it turns in the well bore, carries rock cuttings to the surface, serves as a plaster to prevent the wall of the borehole from crumbling or collapsing, and provides the weight or hydrostatic head to prevent extraneous fluids from entering the well bore and to control downhole pressures that may be encountered. There are basically two types: oil based – which is safer (better at controlling the well) but poor for environment and health and water based – which is more environmentally friendly but not as good for well control. Characteristics of the mud include its weight/density which is measured in pounds per gallon – high ppg = heavy mud can cope with higher pressure. “On balance” is when the mud exerts enough pressure to stop fluids coming in and mud invading the formation. “Over balance” is when the pressure exerted by the mud forces it into the formation and damages the reservoir. “Under balance” is when the pressure exerted by the mud is less than the formation pressure and may thus not suffice to stop formation fluid influx (a kick)