Wellbore Integrity Evaluation Method For Complex Oil And Gas Wells In Tahe Oilfield

The Ordovician in the B area of Tahe oilfield belongs to the ultra deep high temperature and high pressure acid medium gas reservoir,and there are different degrees of wellbore integrity since the trial production.The systematic study of the wellbore integrity of the complex oil and gas wells in the Tahe oilfield can provide technical support for the safe and efficient economic development of the Ordovician and in the B area of the northwest oil field.Based on the current situation of the development of wellbore integrity technology at home and abroad and the extensive investigation of typical failure cases,the analysis of failure modes and causes is carried out to identify the weak parts of the wellbore and provide reference for the study of the wellbore integrity of the complex oil and gas wells in Tahe oilfield.According to the calculation model and field production data of the annular space pressure in the B area of the Tahe oilfield,through the analysis of the oil pipe and the downhole tool and the calculation of the safety factor,the monitoring and management of the hoist pressure in the production period is carried out,and the mechanical analysis of the subwell tools such as the tubing,the packer and the downhole safety valve under different working conditions has been carried out.The influence of the source,temperature and pressure of the annular pressure on the annular oil sleeve pressure and the cause of the abnormal hoist pressure are analyzed,and the minimum safety factor of the pipe column,such as slurry filling,sitting seal,transformation and testing,is determined.Based on the above research results,the process,basis and method of well bore integrity evaluation for complex wells are formulated for different blocks.Finally,taking the Yingshan group typical gas well as an example,the integrity evaluation of wellbore is carried out in this paper.The main considerations are:stress analysis and strength check,casing cementing evaluation and annulus pressure management of tubing,tailpipe and oil casing.According to the research results,suggestions for on-site construction production are provided for reference.