shanly15
Mechanical
- Jul 7, 2007
- 1
Will appreciate your valuable suggestions on feasibility of a process design and required process control for below case.
Well fluids enter a vertical pressure vessel located on wellsite. The well fluid comprise of oil, gas, water and sand. GOR is about 70 m3/m3. Water cut is about 5%. Sand content is about 150 mg/lit. Liquid rate is about 16 m3/hr. Pressure at vessel inlet is about 26 barg. Vessel pressure is to be maintained about the same.
Main objectives are to separate the different components and transport to the production station. Required pressure for this is about 25 barg. Following points may be noted.
- Sand settles at the vessel bottom to be taken by pipe to a production station, using the vessel pressure
- Gas separate from liquids in the vessel. Gas free liquid is fed to a positive displacement pump from a takeoff point below the mid section of the vessel.
- Mixture of gas and liquid is taken from a takeoff point above the mid section of the vessel at the gas liquid interface level (this gas-liquid interface is also expected to serve as an auto liquid level controller)
- The line from the vessel bottom that continuously takes the solids (with some liquid) to the station is joined by the gas liquid line. Thus a single line from the location takes the mixture of sand, liquids and gas to the production station.
Questions are....
- Is it a feasible solution to use the vessel pressure to discharge the gas-liquid mixture (from vessel upper section) and liquid-solids mixture (vessel bottom) joining downstream into a single line? As mentioned above, a third line takes pure liquid (from below the vessel mid-section) to feed the pump suction.
- Is any control instrumentation required to ensure that the liquid level doesn’t drop below the design level (gas and liquid takeoff point). Maintaining this level is important to prevent any gas reaching the pump suction takeoff point?
- What kind of design considerations / control instrumentation will ensure that the sand & liquid from vessel bottom and the liquid gas from the vessel upper part continuously flow without interrupting/ obstructing each other?
See attached a rough schematic of the concept to help visually explain.
Appreciating your valuable feedbacks....
Well fluids enter a vertical pressure vessel located on wellsite. The well fluid comprise of oil, gas, water and sand. GOR is about 70 m3/m3. Water cut is about 5%. Sand content is about 150 mg/lit. Liquid rate is about 16 m3/hr. Pressure at vessel inlet is about 26 barg. Vessel pressure is to be maintained about the same.
Main objectives are to separate the different components and transport to the production station. Required pressure for this is about 25 barg. Following points may be noted.
- Sand settles at the vessel bottom to be taken by pipe to a production station, using the vessel pressure
- Gas separate from liquids in the vessel. Gas free liquid is fed to a positive displacement pump from a takeoff point below the mid section of the vessel.
- Mixture of gas and liquid is taken from a takeoff point above the mid section of the vessel at the gas liquid interface level (this gas-liquid interface is also expected to serve as an auto liquid level controller)
- The line from the vessel bottom that continuously takes the solids (with some liquid) to the station is joined by the gas liquid line. Thus a single line from the location takes the mixture of sand, liquids and gas to the production station.
Questions are....
- Is it a feasible solution to use the vessel pressure to discharge the gas-liquid mixture (from vessel upper section) and liquid-solids mixture (vessel bottom) joining downstream into a single line? As mentioned above, a third line takes pure liquid (from below the vessel mid-section) to feed the pump suction.
- Is any control instrumentation required to ensure that the liquid level doesn’t drop below the design level (gas and liquid takeoff point). Maintaining this level is important to prevent any gas reaching the pump suction takeoff point?
- What kind of design considerations / control instrumentation will ensure that the sand & liquid from vessel bottom and the liquid gas from the vessel upper part continuously flow without interrupting/ obstructing each other?
See attached a rough schematic of the concept to help visually explain.
Appreciating your valuable feedbacks....