Abstract
Often, the production of oil and gas from underground reservoirs is accompanied by produced water which generally increases with time for a matured field, attributable to natural water encroachment, bottom water ingress, coning effect due to higher production rates, channeling effects, etc. This trend poses a production challenge with respect to increased OPEX cost and environmental considerations of treatment/handling and disposal of the produced water considering the late life performance characterized by low reward margins. Hence, produced water management solutions that reduce OPEX cost is key to extending the field life whilst ensuring a positive cash flow for the asset.
SK field is located in the Swamp Area of the Niger Delta, with a capacity of 1.1Bcf gas plant supplying gas to a nearby LNG plant. Oil and gas production from the field is evacuated via the liquid and gas trunk lines respectively. Due to the incessant tampering with oil delivery lines and environmental impact of spillage, the condensate is spiked through the gas trunk line to the LNG plant. Largely, the water/effluent contained in the tank is evacuated through the liquid line. Based on the availability of the liquid line (ca. 40%-60%), the produced water is a constraint to gas production with estimated tank endurance time (ca. 8 days at 500MMscfd). This leads to creaming of gas production and indeed gas deferments due to produced water management, making it difficult to meet the contractual supply obligation to the LNG plant.
An interim solution adopted was to barge the produced water to the oil and gas export terminal, with an associated OPEX cost of ca. US$2Mln/month. Upon further review of an alternate barging option, this option was considered too expensive, inefficient and unsustainable with inherent HSSE exposure. Therefore, a produced water re-injection project was scoped and executed as a viable alternative to produced water management. This option was supported by the Regulators as a preferred option for produced water management for the industry.
A Literature Review of Hybrid System Dynamics and Agent-Based Modeling in a Produced Water Management Context
