Introduction A Flashcards
What methods of artificial lift do we know nowadays?
Rod pumps, Downhole pumps, Gas Lift, Plunger lift.
How does rod pump work?
On each upward stroke, the plunger lifts a volume of oil up and through the wellhead discharge. On the downward stroke it sinks (it should sink, not be pushed) with oil flowing though the valve. About 40 liters per stroke.
What is what there?
How do downhole pumps work?
Downhole pump insert the whole pumping mechanism into the well. Now we use an Electrical Submerged Pump (ESP). Long narrow motor and a multiphase pump, such as a PCP (progressive cavity pump) or centrifugal pump, hangs by an electrical cable.
What is the negative facts about downhole pumps?
Lifetime is sensitive to contaminants such as sand, and efficiency is sensitive to GOR (Gas Oil Ratio) where gas over 10% dramatically lowers efficiency.
How does gas lift work?
Gas Lift injects gas into the well flow.
The downhole reservoir pressure falls off to the wellhead due to the counter pressure from weight of the oil column in the tubing. By injecting gas into this oil, the specific gravity is lowered and the well will start to flow.
Typically gas injected between casing and tubing.
How does plunger lift work? When do we normally use it?
Plunger lift is normally used on low pressure gas wells with some condensate, oil or water, or high gas ratio oil wells.
The cycle starts with the plunger falling into the
well with its valve open. Gas, condensate and oil can pass though the plunger until it reaches bottom. There the valve is closed, now with a volume of oil, condensate or water on top. Gas pressure starts to accumulate under the plunger and after some time pushes the plunger upwards, with liquid on top, which eventually flows out of the wellhead discharge.
What is well workover?
Well workover is the process of performing major maintenance on an oil or gas well. This might include replacement of the tubing, cleanup or new completions, new perforation and various other maintenance works such as installation of gas lift mandrels, new packing etc.
What is well intervention?
Well maintenance without killing the well and performing full
workover is time saving and is often called well intervention.
What is wireline operations?
Various operations that are performed by lowering instruments or tools on a wire into the well are called wireline operations.
What is reservoir stimulation? Why do we need to use it?
Work on the reservoir such as chemical injection, acid treatment, heating etc is referred to as reservoir stimulation. Stimulation serves to correct various forms of formation damage and improve flow.
What damage is? (In terms of reservoir)
Damage is a generic term for accumulation of
particles and fluids that block fractures and pores and limit reservoir permeability.
What is hydraulic fracturing?
Hydraulic fracturing is an operation in which a specially blended liquid is
pumped down a well and into a formation under pressure high enough to
cause the formation to crack open, forming passages through which oil can flow into the well bore.
What is explosive fracturing?
When explosives are used to fracture a formation.
What do you know about coiled tubing?
Flexible coiled tubing can be wound on a large diameter drum and can be inserted and removed much quicker than tubing installed from rigid pipe segments.
