Well Integrity Evaluation and Management: Development and Application of Real Time Online System in High Temperature and High Pressure Gas Wells, Tarim Oilfield
Authors: Cao Lihu , Liu Hongtao , Zhang Bo , Zhang Hongyuan , Kong Change , Liu Wenchao , Zhang Anzhi 
Published: November 2020

Well integrity failure leads to sustaining annular pressure in high temperature and high pressure gas wells. Timely management and evaluation are essential for the safe production and effective measures under such conditions. However, it's difficult for engineers to monitor large numbers of wells located in large area. Therefore, we develop a real-time online system to timely manage and evaluate the integrity of HTHP gas wells to keep safe production and avoid potential accidents.

To develop this system, we build an integrity regulation and database for every stages of HTHP gas wells, including drilling, completion, testing and production. This system has three modules. The first one is to collect production dynamic, formation properties, well structure and strengthen. Second one is to evaluate the potential risk by analyzing well barrier integrity and annular pressure changing trend. Finally, the system provides gas leak path, cement quality, safe annular pressure range and risk level. This system links the oilfield, research institute and field engineers to get timely and effective reaction for the well integrity evaluation and management.

This system has applied to manage and evaluate hundreds of wells in the largest HPHT gas field affiliated to CNPC. The application of this system reduces the cost and burden while improves the management level. This system has developed as a comprehensive well integrity software platform combining data collection, pressure calculation, figure drawing, risk evaluation, report of well condition, statistics of whole filed integrity data and real time monitoring. The annular pressure, production rate, wellhead temperature can be real-time collected and monitored. Once abnormal annular pressure happens, the system can immediately send alert to engineers and administrator. The researchers and engineers can evaluate the risk and integrity status. This system can also provides reliable support to generate a report about how to management gas wells with integrity failure through analyzing the leak path and maximum allowable annular pressure. The figures drawn by the system include well structure, well barrier, leak path, cement quality, risk level matrix, production dynamic curve, allowable annular pressure range and management chart. This drawing makes the well integrity status and management measures vivid for field company administrator, thus helping making rapid and effectively decision.

The system considers every stage of gas wells and combines the function of data collection, pressure calculation, figure drawing, risk evaluation, report of well condition, statistics of filed integrity data and real time monitoring. It makes the work easier and faster for filed engineers. Moreover, it helps filed administrator get comprehensive understanding of well integrity and make reliable decision. The system can also be extended to gas storage and offshore well management.