China Oilfield Services Limited（'Cos'）is the leading integrated oilfield services provider in the offshore China market. Its services cover each phase of offshore oil and gas exploration, development and production. Its four core business segments are geophysical services, drilling services, well services, marine support and transportation services. Cos has listed its H shares on the Main Board of the Stock Exchange of Hong Kong Limited “HK SE” since 20 November 2002 under the ticker 2883. Since 26 March 2004, Cos’s stocks can be traded by means of Level I unlisted American Depositary Receipts at OTC over-the-counter market in the United States. The ticker symbol is Chloe. Cos has listed its A shares on Shanghai Stock Exchange “SSE” under the ticker 601808 since 28 September 2007.

Cos possesses the largest fleet of offshore oilfield services facilities in China. To date, Cos operated and managed a total of 27 drilling rigs of which 23 are jack-up drilling rigs one leased, and 4 are semi-submersible drilling rigs one managed, 2 accommodation rigs, 4 module rigs and 6 land drilling rigs. In addition, Cos also owns and operates the largest and most diverse fleets in offshore China, including more than 80 working vessels and 3 oil tankers, 5 chemical carriers, 8 seismic vessels, 4 surveying vessels, and a vast array of modern facilities and equipment for logging, drilling fluids, directional drilling, cementing and well work-over services, including FTC, EFT, LCD and Eric, etc.

As the largest listed offshore oilfield services company in China, Cos not only provides services of single operations for the customers, but also offers integrated package and turnkey services; Cos’s business activities are conducted not only in offshore China, but also extended to different regions of the world including North and South America, the Middle East, Africa, Europe, South East Asia and Australia. Cos and its employees are dedicated to provide premier quality services, while adhering to the highest health, safety and environmental standards. Cos has obtained the Is International Safety Management certifications, and in 2008, Cos was awarded QHSE management system certificates issued by DNV in compliance with ISO9001, ISO14001 and OHSAS18001 standards.