Abstract

This paper presents the "Re-engineering of Mumbai High Field", the field is located at the western offshore of India. The field re-engineering has been conceptualized through the global business environment, constituting the exploration and production multidisciplinary teams contributing increasingly challenging and costly decisions in realizing early & recurring breakthroughs in the life cycle of oil and gas resources. Mumbai high is a matured oil and gas field producing for more than 30 years. The new technological inputs and engineering resources availability globally have been engaged to maximize the production through redevelopment exercises aptly described as " re-engineering of Mumbai High Field". This involves re-interpretation of 3D seismic attributes and reviewing the geological and reservoir modeling and planning of next phase of redevelopment through five yearly rolling development plans for next 25 years.

To make the organizational activities more effectively, Asset based management system was introduced in the year 2001 to have meaningful authority, responsibility, accountability and empowerment under Corporate Rejuvenation Campaign (CRC). The implementation of Information Consolidation for Efficiency (ICE) - the biggest Enterprise Resource Planning (ERP) under SAP is also one step ahead to tackle the financial and administrative issues of the organization timely and smoothly.

The field re-development exercise of Mumbai High North has been started in December 2000 with an initial cost of Rs 2929 crores ∼ US$ 650 Million & Mumbai High South in October 2001 with an initial cost of Rs. 5226 crores ∼ US﹩ 1160 Million. For redevelopment of the field a pragmatic approach has been conceived through multidisciplinary teams to enhance the production by adopting the frontal technology viz. horizontal, multilateral, high angle and ERD wells utilizing the LWD, RSS, Non-damaging mud system and aggressive side trackingof existing conventional directional wells through LDST, SDST, MRD and SRDH technology utilizing the whip stocks, expandable liners and now fish-tail multilateral are being completed and it is planned to have level-3 multilateral, ultra shot radius and way forward as Under Balance Drilling (UBD) and horizontal wells etc. This involves the higher well cost due to higher rig rate and more operational complications like stuck pipes & mud losses. Enough exercises were envisaged to optimize the cost wherever possible have been reduced about 8 number of well platforms in Mumbai High South through adoption of better drilling technology and facility optimization thereafter. The success of horizontal wells in this exercise have resulted in higher productivity of around 50% than the conventional well which in turn has improved the project viability. The Mumbai High Field is multi-layered limestone reservoir which needs meticulous analysis of geological and reservoir models for better reservoir characterization. In this direction a new approach was sought for production enhancement i.e Integration Asset Model (IAM) and Integration Production Model (IPM) which will provide the philosophy of systematic exploitation of the field with the optimization of surface facility and de-bottle necking the sub-optimal surface input through IAM.

ONGC has bigger plans ahead with respect to improving the recovery factor from the current level of 28% to 40% by 2020 in phases. New technologies are persistently being scouted in the field's perspective & getting infused. Services of domain experts are being sought in the chosen & identified domains like "Reservoir Modeling", "Water flooding", "Artificial lift", "Equipment Management" , "Drilling & Completion technologies", "Produced water conditioning & disposal", "Surface facilities utilization & optimization" & so on. The learning experiences too - both from being in the business for over 30 years and from the recent redevelopment exercises is the basis of road map for long term plan. With all these experiences and with the advice from domain experts, we shall be able to draw a realistic road map for exploiting production from the fields of western offshore for another 30 years or so. The re-engineering exercise of Mumbai High is still on albeit with new dimensions and with new convictions.

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