Surface Facilities Design for the First CO2 EOR Demonstration Project in Saudi Arabia

Abstract

Abstract Saudi Aramco has a strong and extensive history in environmental protection. The list of activities includes energy conservation, flare reduction and carbon management. As part of Saudi Aramco's environmental stewardship program, the company has moved forward, designed and executed its first carbon capture, utilization and storage (CCUS) through an enhanced oil recovery (EOR) demonstration project using carbon dioxide (CO2). The main objectives of the demonstration project are quantifying the amount of CO2 sequestered or stored in the reservoir, addressing the risks and uncertainties involved, including remaining oil saturation, the migration of CO2 within the reservoir, identifying operational concerns, and estimating the incremental oil recovery (beyond waterflooding). Two sets of facilities were specifically constructed for the project: the CO2 capture plant and the produced fluid handling facilities. The CO2 is captured from an industrial plant where it was previously being vented to the atmosphere. It is captured, dehydrated and compressed using a built-for-purpose capturing and compression unit at an existing gas plant facility. The capture plant includes: a seven-stage integrally geared compressor, a tri-ethylene glycol (TEG) dehydration unit located between stages of the integrally geared compressor to dry the CO2, an inter-stage water cooling system, and a dense-phase pump (DPP), which compresses the dry CO2 and then transports it to the field location via an 85 km pipeline for injection. The project includes a row of four injectors and four producers, and two observation wells for monitoring and surveillance. The produced fluids from the EOR wells flow to a nearby gas-oil separation plant (GOSP), where a new stand-alone high-pressure production trap (HPPT), a new compressor and associated facilities have been built for handling the high concentrated CO2 production streams. The produced fluids from the CO2 wells are separated into oil, water and gas, are measured individually, and then connected to the dedicated streams from the GOSP. The HPPT was specially designed and is a fit-for-purpose vessel to handle the produced fluids from the four producers. A unique vertical four-stage compressor was also installed to compress the produced gas. The produced gases are not recycled and join the gas stream going to a gas plant where they are processed and separated. The amount of injected and produced CO2 are measured accurately to determine the amount sequestered in the reservoir. This paper covers the details of the overall facilities design for the first CO2 EOR project in Saudi Arabia.