Oil casings are the lifeline which keep oil wells running. Oil casing needs to bear the complicated force coming from pulling, pressing, curving and twisting under oil well, because of the different geological conditions. Therefore, oil casing needs to have high quality. Once oil casing is damaged for some reasons, it may lead to reduction of output for oil well, even become useless.
Oil casing is a kind of pipe with large diameter, which immobilizes the wall and pit of oil and gas well. Oil casing is used to insert into the oil pit and immobilized with cement, to prevent the well from stratum and collapse, make sure the circular flow of the drilling mud for drilling.
Oil casing is steel pipe that is used to support walls of oil and gas well and assures the operation in and after the drilling process. We need to use several layers of casings based on the different drilling depth and geological conditions for each oil well. We should use cement to immobilize the oil casing after being put in the oil well. Oil casing can't be reused, it belongs to disposable material, which is different from oil pipe or drill pipe. So the consumption of oil casing makes up 70% of the whole oil pipes. Oil casing can be classified into conductor casing, surface casing, intermediate casing, production casing according to its using.
After nearly 20 years' effort, China's oil casing production develops from nothing, low price to high price, low steel grade to API series and to specific requirements, our oil casing products nearly reach international level from quantity to quality. China's oil casing products have taken up over 80% of domestic market and become net export for years in a row.
According to the analysis and forecast report of production and sale requirement and investment of China OCTG industry from 2013 to 2017, Chinese crude oil output reached 204 million tons in 2011, which has increased 0.32% compared with 2010. Gas output got to 102.531 billion cubic meters, increased 6.9%, which reached the highest record. We are still in the rapidly developing stage of urbanization and industrialization, the oil demand in the coming years is expecting to grow about 4%. The increasing demand for oil promotes petroleum drill and exploitation equipment in China.
The demand for OCTG casings no longer focuses on the east of China from geographical view. And if we see it from the trend of oil-gas field, initially develop from east to west, that is, from Daqing, Liaohe, Shengli to Sichuan, Xinjiang. Besides, it is going to develop from land to mudflat, epeiric sea to deep sea. In addition, with the increasing drilling depth, the drilling work is going to be more complicated, which requires more for OCTG casings.