China Oilfield Services Limited, together with its subsidiaries, provides integrated offshore oilfield services in Mainland China and internationally. The company operates through four segments: Geophysical Services, Drilling Services, Well Services, and Marine and Transportation Services. The Geophysical Services segment provides marine seismic acquisition, seismic data processing and interpretation, geo-technical survey, geotechnical and marine environmental investigation, subsea engineering, deep water engineering surveying, groundwork and foundation construction engineering, offshore engineering support, consulting services, and equipment manufacture. The Drilling Services segment provides jack-up drilling rig, semi-submersible drilling rig, modular rig, and land rig services; lift boats and accommodation rigs; and casting and tubing running pipe inspection and repair services. The Well Services segment offers onshore and offshore well services, including logging, drilling and completion fluids, directional drilling, cementing, well completion and workover, stimulation, and oilfield production optimization. The Marine Support Services segment offers anchor handling, towing for drilling rigs/barges, oil lifting, cargo transportation, standby, firefighting, rescue, oil spill response, and other marine support services. The company was incorporated in 2001 and is based in Sanhe, China. China Oilfield Services Limited is a subsidiary of China National Offshore Oil Corporation.