Practical Approach to Greenhouse Gas (GHG) Emissions Reduction in Stranded Oil Producing Assets – Technical Feasibility Safeguards 15MMscf/d Gas Supply

Abstract

Global climate change concerns and the need for decarbonization of the energy sector make it imperative for oil and gas companies to reduce greenhouse - gas (GHG) emissions in their operations. In Nigeria, the Federal Government Gas Commercialization Programme (FGCP) stipulates fines for routine flaring above specified thresholds in Nigeria. Most oil wells in the Niger Delta are produced with Associated Gas (AG) and high gas-oil-ratios (GOR) wells result in significant flares and attendant GHG emissions where there isn't gas gathering facility to process the AG. In addition, the remoteness and unavailability of nearby gas markets in the locations of some assets in the Niger Delta threatens the economic viability of standalone AG processing facility in these assets. Based on these limitations, an optimal solution of re-routing producing wells to the nearest available gas processing facility was assessed for Alpha & Beta Fields. Alpha & Beta Fields commenced production in 1973 without AG processing. Oil production peaked in 1975 at ca. 50kbopd with current production at 11kbopd. The producing reservoirs have a combination drive mechanism with both an active aquifer and a gas cap. Consequently, the wells completed in these reservoirs have a GOR ranging between 500 – 2000scf/bbl and about 15-20MMscf of gas is flared from the facilities daily. To manage the flare volume, the oil wells are typically beaned down to produce on restricted rates, resulting in production deferments. This paper outlines the technical assessments using Integrated Production System Modelling (IPSM) with the Petroleum Expert IPMTM tool to confirm the viability of bulk flowing the wells from the Alpha & Beta Fields to the nearest facility with AG gathering capability to manage flaring, reduce GHG emissions and create value by unlocking additional gas and oil production. Re-routing to the 120MMscf/d capacity AG compression facility, located ~30km from the fields required the isolation of the wells from the existing delivery line and installation of multiphase header and flowmeters. Results of the analysis indicated that the wells could deliver the expected production to High Pressure (HP) Separator in the Central Processing Facility (CPF). In addition, the wells are expected to sustain production with peak gas rate of 15MMscf/d. The project is expected to contribute to the company's net-zero emission ambition through reduction of GHG emission from flares and combustion engines, enable OPEX savings associated with flare penalties and maintenance activities while providing revenue from unlocking oil production as well as the monetization of the produced gas.