Drilling Waste Management: The Policy of Zero Discharge in the Adriatic Sea Activities

Abstract

Abstract At the beginning of the 1980's the introduction in Italy of tighter regulations for protecting the marine environment led to an exhaustive analysis of all the possible technical solutions available to continue the offshore drilling activities in the Italian sector of the Mediterranean Sea in the total respect of the marine life and environment. The results of the studies performed, and mainly devoted to verify the fairness of the new, non-hazardous mud formulations proposed to the industry and the real effectiveness of the systems developed with the goal to minimize the oil content on the cuttings drilled with Oil Base Muds, showed that the new technologies did not give sufficient guarantees for what was concerning their impact on the environment; for these reasons, Agip took the independent (not forced by any Authority) decision to pursue a policy of "zero discharge" at sea in the operations carried out in the Italian waters. This paper, after a review of the legislative developments which took place during the last years, presents the technical solutions adopted by Agip to minimize, first of all, the volumes of wastes created while drilling and producing a well or a field, the logistic solutions envisaged and routinely introduced in order to realize an efficient balance between the normal operations on a platform and the management and disposal alternatives of the various wastes and the more recent contractual forms designed to further improve and optimize treatment and disposal costs, involving in the process also Drilling Contractors and Service Companies. Introduction The search for hydrocarbons offshore by the Oil Industry dates back to the early 50's. Agip drilled its first well offshore in 1959 (it represented also the first trial in Europe) in the Sicily Channel in front of the town of Gela and, from that time to present days, about one thousand wells have been drilled in the Italian waters, in particular in the Adriatic Sea, where most of Agip gas fields are concentrated, and in Sicily. For a certain period of time, more or less till the middle 80's, in absence of a well-articulated environmental legislation regulating in detail the matter, the drilling activities were carried out by using mainly Water Base Muds (WBM) and discharging at sea both fluids and cuttings. The use of Oil Base Muds (OBM) was restricted to particular cases, justified by evident technical needs, such as drilling of highly deviated wells, of overpressured formations with hole instability problems or depleted reservoirs; in these cases, very few during the period, the cuttings were discharged at sea, while the base muds were recovered and brought ashore. During the last 80's, the introduction of more stringent environmental regulations by the Governmental Bodies, the uncertainties pending over the future course of the legislative decisions and tendencies on the matter, experienced not only in Italy but in the majority of the developed Countries, particularly in USA and in North Europe, the steep increase (observed, above all, in Italy) of the bureaucratic requirements to comply with in order to obtain the authorization to discharge at sea the WBMs as well as their cuttings (this aspect became so critical that, in certain circumstances, the delay in receiving the necessary authorization to discharge the wastes caused the postponing of spudding some wells, with obvious, detrimental consequences on the Company exploitation and development plans and, therefore, with strong, negative impact on the costs), the doubts and concerns, still existing within the Oil Industry and the Governmental Entities, about the real effectiveness of the new "green" mud additives and systems to actually minimize the impact on the marine environment of this category of wastes, all these arguments forced Agip to reconsider the entire process and evaluate both from the technical and economical point of view, the various possible options at hand. P. 91^