Feasibility of Conducting Zero Discharge in Offshore Myanmar Drilling Operations

Abstract

International oil and gas operators have been conducting exploration and development drilling in offshore Myanmar since 1990s. There are an increasing number of wells being drilled each year. This paper is intended to discuss on drilling discharge operations due to the fact that, Myanmar have gradually introduced new environmental regulations and guidelines since 2015 based on guidelines from International Finance Cooperation (IFC) from World Bank. Generally, oil and gas operators have used various Water Based Mud (WBM) and synthetic based mud (SBM) systems in drilling operations. The usage of SBM is generally used to reduce drilling operations problems related to formation. Along with the usage of SBM trend, new discharge regulations were also implemented in various countries. Some countries establish the strictest regulation on discharging drilling waste (Zero Discharge). This paper will emphasized on the feasibility of conducting zero discharge in offshore Myanmar. Zero discharge is conducted in areas where regulations dictates. The aim of zero discharge from drilling activities to the sea was introduced in Sorting White Paper No. 58 (1996-97) by Norweigian authorities. In early oil and gas development periods, drilling waste were generally discharged from the platforms directly to the sea without any limitations. In March 1991 US Environmental Protection Agency (USEPA) implemented all discharges to comply with fixed limitations and required zero discharge for wells drilled within four miles or less from shore. Zero discharge are required for wells drilled at a distance of four miles or less from shore. Discharge from wells drilled at a distance greater than four miles from shore were proposed to be limited by a prohibition on the discharge of free oil. This is achieved by usage of Best Available Technology (BAT) equipment’s such as cutting dryer, during that time. This limits the oil on cutting (OOC) discharges to <6.9% for drill cuttings for specific base oil. Additional requirements for drilling fluids discharges: (1) Toxicity limitation set at 30,000 ppm in the suspended particulate phase; (2) a prohibition on the discharge of detectable amounts of diesel oil used either for lubricity or spotting purposes; (3) no discharge of free oil based on the static sheen test; and (4) limitations for 3mg/kg cadmium and 1mg/kg mercury in the stock barite. In Myanmar, guidelines were issued by host authority for waste discharge according to IFC regulations. This is similar to the regulations from USEPA agency. In Myanmar, offshore exploration and appraisal well was drilled at M12, Gulf of Mottama in November, 1992 and followed by development wells in 1996-1997. This is the first offshore drilling in Myanmar and this was followed by other offshore fields such as Yadana, in Gulf of Mottama, Shwe in Bay of Bengal and Zawtika fields in Gulf of Martaban. No operators have adopted zero discharge drilling in offshore Myanmar yet. Drill cuttings and drilling fluids discharge is the main waste stream from drilling activity. Host governments are imposing regulations and guidelines on the drill cuttings management. Zero discharge is one the strictest legislation of drilling fluids and cuttings waste management. This paper will focus on the feasibility of conducting zero discharge in Myanmar offshore drilling operations. The paper shall discuss the drilling operations limitations and costings to implement zero discharge from Yetagun field. The paper will also highlight the differences in South East Asian countries regulations for zero discharge requirements.

AAPG Datapages/Search and Discovery Article #90336 ©2018 AAPG Asia Pacific Region, The 4th AAPG/EAGE/MGS Myanmar Oil and Gas Conference, Myanmar: A Global Oil and Gas Hotspot: Unleashing the Petroleum Systems Potential, Yangon, Myanmar, November 13-15, 2018