Water Disposal Options for Small and Stranded Assets in the Niger Delta

Abstract

The conventional produced water disposal options approved under the Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN) for inland and nearshore assets in Nigeria is water re-injection for reservoir pressure maintenance and injection into disposal wells. Full compliance to these regulatory requirements would need the drilling of injectors, or conversion of old producer wells to injector wells. These traditional practices are however not feasible for small assets with marginally profitable resource volumes, or for stranded assets which require huge investments for evacuation of well fluids to third-party facilities. Such operators are unable to drill injectors due to the massive financial implications of such an operation. One of the ways of overcoming this challenge in a small and stranded asset in the Niger Delta is to consider alternative and innovative water disposal options to manage water production. This paper explores the concept of produced water management in small and/or stranded assets in the oil and gas industry with no proximity to processing infrastructures. The study reviewed the available water management techniques in the oil and gas industry. Furthermore, this study investigated and evaluated alternative water disposal options suitable for small stranded assets in the Niger Delta. The proposed alternative methods include; evaporation (natural, solar-driven, and flare-assisted evaporation), collaborative water disposal arrangement and onsite water treatment and reuse. A techno-economic analysis of the proposed methods was conducted to inform the choice of any of the proposed water disposal methods. The field life considered for the analysis was 15 years. The results showed that the cost of drilling an injector well increased capital expenditure significantly; $945.9 million compared to the alternative disposal methods (evaporation = 376.1 million, collaborative disposal = 258.8 million and membrane distillation = 404.7 million). Analysis showed that adopting evaporation, membrane distillation and collaborative disposal resulted in cost savings of $569.8 million, $541.2 million and $687.4 million respectively. Proper considerations of the findings of this paper will aid the operators of small and stranded assets in managing produced water effectively and economically within the regulations of EGASPIN which permits; no discharge of produced water into the surrounding inland and nearshore fields.