"Since the launch of the tubing joint strength influence factors and standardized technology research project, has achieved initial success, we apply a new short structure the patented technology, the tubing joint improved, have not occurred again with short slip accident." Lv Qinggang, director of the center for quality supervision and control of the oil field in the northwest, is pleased to say.

In recent years, points within the area of the company in the event of a failure to the tubing joint, such as the 2007 TK1025 well; 2009 yk8, YK14 well; 2011 S1072-2 well; 2012 BT5, TP148, Shun 9 well etc., the preliminary estimated economic loss of about 800 million yuan. Most failure analysis revealed that the short joint of the oil pipe material in line with company standard, the main failure mechanism for tensile overload fracture, this and short processing quality, field operation and connecting structure has the very big relations, especially with tubing hanging connected double male joint, the tubing hanger of wall thickness is far greater than the wall thickness of the short, resulting in tubing joint stress concentration, the connection strength is greatly reduced.

Northwest Oilfield Property Management Center of quality supervision department for safety production tubing joint failure to carry out technology research, they happened since 2011 more than 10 tubing failure, focus on analysis, established short joint of the oil pipe and tubing coupling model and the short joint of the oil pipe and the oil pipe hanger is connected model, completed the 32 finite element analysis cases, double male joint and the oil pipe hanging on the buckle torque analysis, a tubing nipple thread joints in under the condition of tensile failure analysis of the law, and clarify the effect of tubing joint failure pattern and main reason, to determine the influence of tubing joint strength of the main factors and key parameters control index.

Through the research, they worked out tubing short processing specifications and drawings, a tubing nipple order supplement technology conditions, a tubing nipple site operating norms, such as, to double male joint of stress analysis, determines the operation process and the lifting force. To optimize the structure and size of tubing nipple, nipple type by more than 30 kinds of simplified into 5 basic types. The short joint of the oil pipe and the oil pipe hanging field button control method and field application achieved good results, effectively reduce the tubing joint failure, improve the quality management level of the tubing joint, in tubing joint failure mechanism study, discovered for the first time external thread pipe end eccentricity of short connection strength was influenced the optimized for short structure, improve the short connection strength has important value.

"By improving the production tubing joint structure and specification tubing joint, use, engaged in the recovery transformation for the prior control and prevention, can significantly improve the tubing joint quality and service life, reduce the incidence of tubing joint failure accident of, for has very important economic value and social benefit safeguard company oil and gas Tian Anquan efficient production." Lv Qinggang minister to us.