SHOTGUNS, SPRAY, AND SMOKE: REGULATING ATMOSPHERIC DEPOSITION OF POLLUTANTS UNDER THE CLEAN WATER ACT
CHAPTER ONE
INTRODUCTION
The Exploration and Development activities for oil and gas involve seismic, drilling and well completion. Each phase differs to some extent in type and quantity of pollutants discharged. In Nigeria, the exploration and development activities may be found onshore, shallow (including swamps, coastal waters, estuaries, rivers, etc.) and deep offshore waters. These physical locations influence the manner in which the operations are conducted, and the effluents are treated and discharged. The relevant legal authority is provided for by the Petroleum Act 1969 with the Petroleum (Drilling and Production) Regulation 1969, Sections 25 and 36. Also the Explosive Act 1964 and Explosive Regulation 1967 govern the use of explosives during seismic activities. The main purposes of these guidelines and standards are to establish an effective uniform monitoring and control programme for the discharges arising from oil exploration and development and to ensure compliance with sound and efficient environmental management by all operators.
Exploration usually consists of special surveys, such as seismic, gravimetric & magnetic, to determine the subsurface structure and to estimate the potential for oil and/or gas accumulation. Having established the existence of favourable conditions, wells are drilled to determine the nature and extent of potential hydrocarbon reservoirs.
Exploratory drilling is performed with a rotary drill outfitted to a mobile rig for drilling wells and for determining the nature and extent of potential hydrocarbon reservoirs. Rig designs used in Nigeria are those for land, deep and shallow water drilling. The main purpose of an exploration rig is to house rotary drilling equipment whose only function is to make a hole. There are four main subsystems to perform this function, power, hoisting, rotating, and circulating. In addition, facilities for supporting a work crew (living, dining, etc.) for extended periods must be available. In Nigeria, two types of drilling muds - water based, and oil based (mineral/synthetic or pseudo) muds - are used. Drilling mud is a constantly circulating medium of communication to the surface of down hole conditions. It carries warnings of impending kicks, and