Environmental Considerations for Transferring Offshore Facilities to National Oil Company Operators

Abstract

As the governments of developing nations strive to increase indigenous expertise in offshore oil exploration and development, the industry is also dealing with offshore concession (or lease) expirations on older fields that are to revert back to operation by national oil companies for the remainder of the life of the field. Unlike onshore developments, for which property transfer (or asset divestiture) due diligence protocols have been developed (E&P Forum 1996), few if any industry protocols address environmental risk management for the transfer of offshore facilities. Additionally, the longer-term operation of offshore facilities, from equipment/facility integrity, sustainability, and impacts to the environment during the transition period, needs to be considered by the divesting entity, such that national oil company operators have a clear understanding of the development and its future operation. This paper presents property transfer practices developed for offshore/subsea environmental sampling, including sampling design/program development, sampling protocol, and lessons learned from the implementation of such a sampling program. Additionally, a model for performing a property transfer Phase 1 Environmental Site Assessment (ESA) for an offshore development consisting of a wide range of facilities including well jackets, processing platforms, and accommodations platforms is presented. The results of the environmental sampling and property transfer Phase 1 ESA then provide a baseline to protect the original operator from future claims of subsea pollution or unacceptable environmental operating practices. Alternatively, if subsea pollution is identified, best management practices or safeguards protective of human health and the environment (e.g., fishing restrictions) can be implemented. Introduction The last 20 years have seen significant advancement in environmental controls associated with oil production. New technologies have emerged that have lessened environmental impacts, and new information regarding the impacts of certain activities has helped drive environmental policy and regulations. As a result, current environmental expectations associated with an older oil producing field are in many respects greater than they were when the field was originally developed, as well as during different periods in the life of production. For onshore developments, investigations and/or remedial actions have been taken in many fields to remove or minimize environmental impacts associated with past practices. However, it is more difficult to identify environmental impacts of past practices in the marine environment. The marine environment is dynamic, so it is difficult to imagine the impacts of drilling, produced water discharges, etc., after decades of operation. Additionally, visual inspections are not easily performed and even with subsea cameras, colors and patterns are often difficult to see. However, in some cases residual impacts occur, and it is becoming increasingly important to understand those impacts, especially in a property transfer situation. The two main steps associated with transferring an offshore property are performance of a property transfer Phase 1 ESA and Environmental Sampling (the sampling could be compared to a Phase 2 ESA, though the scope and logistics are different). These two steps are described below.

Features of localization of remaining oil in terrigenous reservoirs and potential for their recovery at the final stage of field development

“…The purpose of the study is to increase the degree of development of reserves by summarizing the indicators of the long history of field development and assessing the possibilities of introducing modern oil recovery methods. Therefore, the main tasks at the current stage of field development are as follows: localization of remaining oil in place, assessment of the efficiency of geological and technological measures (GTM), development of enhanced oil recovery strategy, and expansion of the detailed targeted program of geological and technical measures in the context of the complex geological structure of the field [9,10].…”