This paper highlights several opportunities to maximize the total crude oil yield of typical Gas Oil Separation Plants (GOSP's), gas handling and crude oil stabilization systems. This can be achieved for existing facilities by optimizing operating parameters without capital cost or plant modification. Maximizing GOSP's yield (oil recovery) has many advantages such as revenue generation, reducing energy requirements of associated gas handling, mitigating export gas transportation challenges as well as reducing capital cost for new facilities.
Throughout three case studies, this paper demonstrates the impact of operating parameters change in reducing GOSP's total oil shrinkage:
Case Study-1: Pressure let-down optimization of multistage separation
Case Study-2: Temperature optimization of compressors after-coolers
Case Study-3: Temperature optimization of crude stabilization
The analysis was performed for each case study utilizing HYSYS process simulation to establish the optimum operating window for the subject process area. The theoretical results were advanced by conducted field trials under governing operating procedures to validate the conclusion and further explore the benefits as well as the potential challenges of these opportunities.
In case study 1, for high GOR GOSP where more than 3 stages of pressure letdown are required, pressure optimization of the intermediate and low pressure gas/oil separation stages achieved an oil output increase of 3.5 MBD for the same base rate (500 MBD) with dropping gas compression power requirement by 10 MW.
In case study 2, for GOSP's where steady-state hydrocarbon condensate recovered from compressors after coolers knock-out drums is spiked into main Light crude production, optimizing air coolers operating conditions result in a gain of up to 2 MBD in export oil for the same base rate (200 MBD). Moreover, 50% drop in export gas water load can be achieved which helps mitigating pipeline corrosion challenges in gas transportation given the unavailability of a gas dehydration system in the facility.
In case study 3, optimizing inlet temperature of light crude stabilizer enhanced column stripping capability and enabled meeting the required H2S and vapor pressure specification with minimum hydrocarbon liquids losses. A Reduction of 20 °F in inlet temperature resulted in savings of up to 2 MBD stock tank crude for the same base rate of 500 MBD in the expense of reboiler's duty.
