Integrity Management and Risk Control of Oil Well Drilling Tools

In the complex oil and gas well drilling process such as deep wells, ultra-deep wells, horizontal wells and branch wells, the downhole drilling tools are prone to fractures and punctures due to the complex dynamic loads of tension, compression, bending, and torsion and wellbore media conditions. When the drilling tool fails, it will seriously affect the safety of drilling. In recent years, with the continuous increase in the number of complex oil and gas wells drilled, the problem of drilling tool failure has become increasingly prominent. How to timely and accurately grasp the technical status of in-service drilling tools, implement more scientific drilling tool integrity management, and prevent drill tools from re-entering the well and cause downhole failures, is a major issue that needs to be resolved urgently in complex oil and gas well drilling engineering.

At present, oilfields generally adopt a drill tool classification management model, which mainly relies on comprehensive inspection methods to conduct regular inspections of in-service drilling tools, and classify drilling tools according to the inspection results, and select corresponding grades of drilling tools according to specific well conditions. Although this management mode guarantees the reasonable utilization of drilling tools and the reliability of drilling tools into the well to a certain extent, there are still some problems: 

(1) For complex oil and gas wells, different blocks, different well types, different well depths and Under different conditions of use, there are obvious differences in the damage rules of drilling tools. The inspection and classification of drilling tools according to the inspection cycle determined by experience cannot accurately reflect the technical status of the drilling tools under complex working conditions, and it is difficult to ensure the reliability of the drilling tools;

(2) Regardless of the specific usage of oil well drilling tools, it will cost huge transfer costs and inspection costs to transport batches of drilling tools to the base regularly for systematic inspection and classification; 

(3) Because the existing conventional non-destructive inspection technology cannot reflect the thread of the drill tool joint At present, for drilling tools that have experienced bad well conditions, only cutting and repairing measures can be taken to improve or reduce the stress concentration of the sensitive parts of the joint thread. This has shortened the service life of the normal-state drilling tools, causing unnecessary resource waste of drilling tools.