Abstract

The new OSPAR regulation (OSPAR 2000/3) on drill cuttings is due to be effective by January 2005 at the Norwegian continental shelf. Drilling operations planned to be performed from to date and onwards therefore have to take into account that the forthcoming regulation has important implications with respect to selection of adequate and compliant technology.

Drilling will commence at a new HTHP Statoil operated field offshore middle Norway, by late summer 2003. Ahead of the spudding in, a detailed and comprehensive review of technological solutions has been carried out to resolve the issues of zero discharge and use of best available technique.

The paper describes the challenges associated with the forthcoming zero discharge regulation and the different technological scenarios that have been reviewed. Waste minimisation methodology has been of major importance in the decision process. Treatment of oily drilling waste, applying new technology at the rig, was studied in detail. The respective energy budgets, environmental impacts and risks associated with the different solutions are also presented, as well as a suggested best technique.

The paper offers a study of how operators may comply with a zero discharge in drilling operations, with reference to BAT (best available technique). On a general basis the ultimate goal of environmental legislation is discussed with reference to the forthcoming discharge regime and how to decide BAT; achieving the right balance between technology and value.

Introduction

Statoil ASA is the operator of a sub-sea high temperature high pressure (HTHP) gas and condensate field offshore mid-Norway.

Due to increasingly tighter legislation and regulations with respect to discharges and emissions during drilling operations applied drilling and waste technologies must be of a high standard. Further, for confidence building preferred technological solution should be accompanied by a transparent decision making procedure, allowing insight for any stakeholder.

Recognizing that no common acknowledged formula exists, e.g.: a discriminative instruction for deriving at an exact solution, decisions related to drill cuttings disposal have to be weighted up against several adequate issues. The new OSPAR regulation (1) on drill cuttings is due to be effective by January 2005 at the Norwegian continental shelf. The zero discharge regime will then prevail. The planned drilling operations aspire to comply with this regime. A European Council Directive (2), the "IPPC Directive" is also important, as a secondary legislation adopted to pursue a certain purpose within a given hierarchy and legal framework. Of particular interest is how this Directive addresses the concept of new technology aiming to qualify as best available under the terms of the Directive (BAT = Best Available Technique). The "integrated approach" pursued under the IPPC Directive is essential as it addresses the problem of a number of highly undesirable environmental impact "transfers" that resulted from previous discrete, source specific legislation:

  • "shifting of pollution" from one media to another,

  • shifting of pollution between different geographical areas,

  • and the replacement of pollution emissions by increased energy and/or material consumption.

Balancing zero discharge and BAT is by no means straightforward. In order to comply with the new legislation and regulation a detailed and comprehensive review of technological solutions was carried out to resolve the issue of zero discharge and use of BAT. As will be presented a new offshore waste minimization technology, a hammermill unit (TCC) capable to treat drilling waste at the drilling rig was evaluated as a possible BAT. This technology in many respects intensifies the discussion about right or wrong decisions, and therefore the implication of this technology is given particular attention. Is a literally zero discharge regime justified, and can it be defended against the renunciations it apparently encompasses? This is an intriguing question that tickles the wits of stakeholders.

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