Exploration Drilling in the Russian Far East: Two Years of Experience and Learning Offshore Sakhalin Island

Abstract

An exploration well drilled by a joint venture between Rosneft and BP in the summer of 2004 was the first success after a long period of no exploration activity. It represented a step out into a new and untested exploration play. Wells in Sakhalin involve a permitting cycle that lasts for 7 months and a logistical supply chain that extends 3,500 miles back to Singapore, Figure 1. The sea ice-free weather window lasts from late June until mid-November, with severe storms building from September onwards. Environmental restrictions stipulate that all mud and cuttings from below the 30″ conductor, even though the well may be drilled with a water-based mud, cannot be discharged to the environment and must be recovered for disposal. The team overcame a wide range of organisational, logistical, regulatory, environmental and technical challenges to drill the well in the summer of 2004. Despite the highly compressed schedule, the operation was conducted with no harm to people or damage to the environment. The lessons learned were consolidated and formed the basis for a successful season in 2005 with a different rig. Introduction Oil has been produced from Sakhalin since the 1920s. Offshore exploration was carried out in the 1970s and 1980s leading to the discovery of the major fields presently being developed by the Sakhalin 1 and Sakhalin 2 Production Sharing Agreements, figure 2. In 1996, Marathon published an account of their 1992 operation, reference 1, describing how they drilled their early appraisal wells using mostly locally supplied drilling units, aviation support and services. At that time it was still possible to obtain a permit to discharge drilling fluids and cuttings to the sea and Marathon carried out significant work to compare the discharge requirements in Russia with those in Europe and the USA, reference 2. BP is a 49% shareholder in a joint venture with Rosneft. The operations base is located in Yuzhno-Sakhalinsk at the South end of Sakhalin Island (47 deg N, 143 deg E). The operation takes place offshore at the North end of the Island, in about 100 m water, 500 miles away from the base office, figure 2. Although the southern Sakhalin ports are ice-free all year round, the main logistics base at Moskalvo, in the North, is only accessible from early June and freezes up in early November. The drilling location is clear of ice by late June. The weather is generally fine during the summer although typhoons moving north from Japan can give rise to storms with 90 kt gusts. Weather forecasting is difficult, the consistency being low. Storms gather pace rapidly during September and remain intense through the winter. The Organisation Within the Joint Venture Company, Rosneft personnel contribute their understanding of operations in Russia while the BP heritage staff brings their technical knowledge of safe operations in remote harsh environments. The operations team is based in Sakhalin. After the initial phase in 2003, all the engineering, logistics and permitting activities were carried out on the Island. The subsurface team are located in Houston. The project team is responsible for executing the entire scope of the activity. With limited infrastructure, this involves: well engineering, operations supervision, aviation, logistics, shore base, incident management, blowout contingency planning, health, safety, environmental compliance, cuttings disposal, permitting, IT systems and all aspects of telecommunications. In 2003 a project organisation was created to fulfil all of these functions based on experience from earlier campaigns, reference 3. With continued operations, this has now evolved into a permanent team staffed on a rotational basis.