With soaring global demand, depleting supplies of crude oil coupled with the collapse in the oil prices, maximizing oil production in mature fields has become a priority. Such fields account for over 70% of the world's oil and gas production, with a worldwide average recovery factor of 35% for oil. Main challenge encountered by mature oil fields is the well pressure depletion over time. Since pressure depletion is inevitable, it is particularly challenging to continue to produce as there is insufficient reservoir pressure to push the well fluids to the main processing facilities.
The system discussed in this paper is an effective engineering solution designed for topside receiving facilities. The Low Pressure Production Unit ‘LPPU’ is a separation system for boosting the pressure of production fluids from low pressure wells. It is ideally suited for remote wellhead platforms where wells have insufficient pressure to deliver well fluids to production header, space is a constraint, and manning is not required.
Conceptual design of this system is based on the very low, almost atmospheric, operating pressure of the system, wherein the flow from the well to topside becomes easier without the need to inject the well itself with any foreign elements. The system is designed in such a way that it can receive continuous full flow from the well, and still manages –through intricate isolation methodology- to operate in batches. This batch operation arrangement allows for liquid accumulation which is then discharged to the production header after being pressurized.
System adopts different variations based on availability; it either uses HP gas -typically from existing gas-lift compressor from the main processing platform- or compresses the associated gas from the FWS to be used as ‘motive gas’ which is used to pressurize and push down the accumulated liquid towards the delivery of flow to the production header.
A characteristic optimization factor that contributes greatly to the economic and operational attraction of this system is its ability to utilize its equipment to combine solutions for the two challenges of 1-reduced pressure that's beneficial to the well flow, and 2-the higher pressure essential for the production header.