This paper presents the concepts for two new artificial lift systems. The systems utilize the same operating principles. One system is for oil wells, the other unloads gas wells. The first system uses gas pressure to produce liquids through the tubing. This is called a Hydraulic Gas Pump. The other system uses gas pressure to unload gas wells and is called Gas Well De-watering System. In this system gas is produced through the tubing and liquid is produced through the casing tubing annulus.
The Hydraulic Gas Pump is suitable to pump oil wells with high gas liquid ratio and viscous crude production. The De-watering System can be used to maintain a gas well in an unloaded condition for maximizing its production rate and recoverable reserves.
Additional advantages of these systems are:
* They can be installed in shallow, deep, directional or offshorewells.* They are wireline retrievable systems.* Gas Lock and cavitation are not problems.* They preform well in corrosive environments.
The existing pumps for oil wells such as rod pumps, electric and hydraulic pumps have operational problems when they are installed in wells that produce viscous oil, sand or high gas liquid ratio fluids. In gassy wells, inefficient operation, reduction in lift capacity and gas locking can be expected. In viscous oil production rod fall problem can cause frequent mechanical failures for rod pumps. Rod pumping is difficult in crooked, directional or deep wells. For offshore wells, if gas lift or electric submersible pumps are not applicable, there is no other good artificial lift choice.
One type of pump that operates well in the producing environments listed in the above paragraph is the gas chamber pump (Reference 1). These pumps can pump any kind of fluid, from gassy fluids to viscous crude with or without entrained sand. They can be installed in crooked, deviated, high temperature well bores. In other words the gas chamber pump is an excellent pump, except for its major disadvantage that it is limited to shallow wells.
The Hydraulic Gas Pump introduces a new pumping technique that has the same operational advantages as a gas chamber pump in addition it will be able to pump liquids from deep depths. As a result it has the potential of becoming a useful artificial lift device for oil wells.