Abstract
With an average gross operated production of 211,671 boepd in FY2015, Cairn India Limited (CIL) is the largest private sector producer of crude oil in India. In FY 14-15, around 120 wells were drilled in Mangala, Bhagyam and Aishwariya alone. Waste water generation in Operations has seen a massive increase in recent years because of increased production and an aggressive drilling campaign.
CIL operates on Zero Surface Effluent discharge philosophy making it imperative to deliberate on waste water disposal strategy. Managing the huge volumes of waste water in a sustainable manner is a challenge. Accordingly, waste water treatment plant for reuse and waste pits and guard ponds were created to evaporate waste water. Due to waxy nature of oil in waste water, high level of suspended solids and bacterial degradation, natural evaporation is almost negligible. Waste water accumulation over a long period of time has resulted in inventory buildup of all the pits. It has become business critical requiring strategic focus to ensure business continuity and sustainability.
Given the challenges of waste water management in onshore Oil & Gas operations, the paper describes the various technologies available in the market and tested by Cairn, results of market studies carried including pros and cons of each option, followed by pilot-scale implementation of the chosen technologies. The paper not only describes the success of the pilot studies and the related technical aspects, but also the commercial, socio-economic and stakeholder challenges and the approach to applying the selected option for full-field implementation. The paper concludes with suggested way forward for full-field implementation including associated challenges and success factors.
The objective of this paper is to share the experiences of an operating company with other oil & gas Companies worldwide on various aspects relating to waste water treatment and management in onshore oil & gas operations. The typical process for an Oil & Gas Operator is to evaluate all aspects, right from technology finalization to economic optimization and finally develop an integrated roadmap for the entire project. A firm methodology was adopted to validate the technical as well as the commercial aspects of the project. The final treated water is put for reuse thereby delivering twin benefits in terms of handling waste water in a sustainable manner as well as optimizing the water footprint.
