Vapor control for storage tank with pump off unit
OwnerRandy Swaninventor
Life of this patent
Estimating the term…
Abstract
A system and method removes well fluids, which include gas and liquids, from a storage tank. The storage tank has a gas relief valve that opens to admit atmospheric air into the storage tank when the pressure of a gas cap decreases below a vacuum threshold pressure. Well fluids flow into the storage tank and the level of liquid is monitored. When the level reaches a first level, a pump is operated by a controller to remove liquid from the storage tank. The pressure in the gas cap is monitored while the pump is operating. The speed of the pump is adjusted to maintain the gas cap pressure above the predetermined pressure and avoid the introduction of atmospheric air into the gas cap.
Claims20
A well fluid storage system, comprising:
- a) a storage tank capable of holding well fluids, the storage tank having a gas cap located above a liquid, the storage tank having a fluid inlet, a liquid outlet and a gas outlet, the storage tank having a gas pressure relief valve that opens when gas pressure inside the storage tank decreases below a vacuum threshold pressure;
- b) a pump connected to the liquid outlet;
- c) a controller system comprising:
- i) a drive coupled to and operating the pump at a variable speed;
- ii) a gas pressure sensor in communication with the gas cap in the storage tank;
- iii) a controller connected to the gas pressure sensor and the drive, the controller operating the drive to slow the pump speed as the pressure in the gas cap decreases toward the vacuum threshold pressure so as to maintain the gas pressure relief valve in a closed condition.
A method of removing well fluids from a storage tank, the well fluids comprising gas and liquid, the gas located in a gas cap in the storage tank, the storage tank having a gas relief valve that opens to admit atmospheric air into the storage tank when the pressure of the gas cap decreases below a vacuum threshold pressure, comprising the steps of:
- a) allowing well fluids to flow into the storage tank;
- b) monitoring a level of liquid in the storage tank;
- c) operating a pump at a speed to remove liquid from the storage tank when the liquid level reaches a first level;
- d) monitoring pressure of the gas cap while the pump is operating;
- e) adjusting the speed of the pump to maintain the gas cap pressure above the predetermined pressure and avoid the introduction of atmospheric air into the gas cap.
Dependencies are inferred from the claim text.