China Oilfield Services Limited, together with its subsidiaries, provides integrated offshore oilfield services in Mainland China and internationally. The company operates through four segments: Drilling Services, Well Services, Marine Support Services, and Geophysical Acquisition and Surveying Services. The Drilling Services segment provides jack-up drilling rig, semi-submersible drilling rig, modular rig, and land drilling rig services; and casting and tubing, and running pipe inspection and repair services. This segment operates and manages 36 jack-up drilling rigs, 12 semi-submersible drilling rigs, and 6 modular rigs. 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 of drilling rigs/engineering barges, oil lifting, offshore transportation, standby, firefighting, rescue, oil spill assisting, and other marine support services. It operates and manages approximately 130 vessels, including anchor-handling tug/supply, platform supply, and multi-purpose vessels, as well as barges and shuttle-tankers. The Geophysical Acquisition and Surveying Services segment provides marine seismic acquisition, offshore geo-surveying, seismic data processing and interpretation, and underwater engineering services. This segment owns 6 seismic vessels, 2 ocean bottle cable teams, and 5 engineering surveying vessels. China Oilfield Services Limited also issues bonds. The company is based in Sanhe, China. China Oilfield Services Limited is a subsidiary of China National Offshore Oil Corporation.