On the early morning of May 13th,the first N80Q SEW oil casing pipes with DN139.7 mm and WT9.17 mm are independently developed by Baoji Petroleum Steel Pipe Co., Ltd  succeeded in going down a well once in Qinghai oilfield,which marks that Baoji high-grade octg steel pipe development has entered the applied stage.

SEW oil casing used TMCP rolled coils with high-dimensional accuracy control as raw material.Products with low energy consumption,high performance and high value-added are produced with the process of "high frequency welding tube and special heat treatment", which is not provided with good quality, high geometric accuracy, good anti-collapse performance and high material toughness , but also has  advantages of high frequency welded pipe and seamless pipe in the production process.That can greatly reduce the cost of oil well drilling.

In order to ensure this success in downhole work,Baoji steel pipe Co., Ltd conducted several technical exchanges with Qinghai oilfield. At 12 am on May 12th , the first N80Q SEW oil casing pipe started to descend the well, screw on smoothly and quickly. It only took 7.5 hours to finish descending 178 pipes in the well. It has been tested that colliding pressure was 22 MPa; stabilivolt for 4 minutes, 0 mpa of pressure drop after completing well cementation,which showed that the used oil casing pipes had good sealing, without any leakage.

As a domestic enterprise that was the first to carry out the research and development of SEW oil casing pipes , Baoji steel pipe Co., Ltd have completed a number of trial-produce tasks for new products since 2009. Among them, J55 and N80Q SEW oil casing pipes have tested evaluated through national OCTG quality supervision and test center, and have achieved API manufacturing license.

In 2011 August, Baoji steel pipe have built Asian first SEW oil casing production line with the highest level of equipment accross the country. Not only can produce oil casing pipes with various steel grade conforming to the API standard, but also can manufacture non API oil casing pipes with high toughness and high strength for special purpose.