Well integrity/control

Well Integrity

Statistics on well-integrity incidents are difficult to find in the literature. There are some examples of kick and blowout events, but normally they are scarce and focus on the number of incidents and their root causes.

Statistics on well-integrity incidents are difficult to find in the literature. There are some examples of kick and blowout events, but normally they are scarce and focus on the number of incidents and their root causes. There is, however, one example of statistics that has been inspiring me throughout the years when I prepare my lectures on how we can drill, complete, and produce wells safely. It is one that is presented in the excellent textbook on high-pressure/high-temperature wells published by Aberdeen Drilling Schools that shows human factors related to offshore blowouts. On the basis of those statistics, I divided these factors into four groups: (1) inattention to operations (25%) and inadequate supervision/work supervision (20%); (2) improper maintenance of equipment (20%) and improper installation/inspection of equipment (2%); (3) inadequate documentation (2%) and improper method or procedure (11%); and (4) improper planning (12%). No direct human error involved was stated for the remaining 8%. Here, I will show how these factors can be addressed to make a well-integrity system efficient.

The first group represents 45% of the human factors related to offshore blowouts. One efficient way to address it is through training and assurance of personnel competence. A well-integrity system implemented by any company of the oil industry can be robust only if it strongly considers this aspect. Regrettably, this topic only barely appears in the literature and conferences on the topic of well integrity. Recently, the International Oil and Gas Producers Association presented appropriate recommendations for technical enhancements to well-control training, examination, and certification that can be extended to other activities related to well integrity.

The second group encompasses well-equipment-related issues. An adequate well-integrity system should have the necessary safety barriers in place, understood, tested, verified, and maintained. It should also have proper contingencies in case of failure of these primary barriers.

The third group refers to documentation. Currently, there is a strong movement toward elaborating or revising regulations related to well integrity by entities such as the American Petroleum Institute and the International Organization for Standardization. Creation of new or improvement of existing design and operational procedures that result in safer operations throughout a well’s life cycle is mandatory for an effective well-integrity system. It is also important that any well-integrity anomaly be documented, analyzed, and transmitted to all involved parties.

The last group refers to planning. Many well failures are a result of poor well design and operation planning. A strong well-integrity system should rely deeply on approaches such as risk assessment, management of changes, action plans, and design basis.

This Month's Technical Papers

Uncertainty Evaluation of Wellbore-Stability-Model Predictions

Zonal Isolation Through Gas Hydrates Offshore Tanzania

Perforating Through Casing Strings To Remediate Annulus Gas Leak

Recommended Additional Reading

SPE/IADC 163417 Detection of Kicks Prompted by Losses and Direct-Measurement Well-Control Method Through Networked Drillstring With Along-String Pressure Evaluation by Daan Veeningen, NOV IntelliServ

SPE/IADC 163445 Feasibility Study of Applying Intelligent Drillpipe in Early Detection of Gas Influx During Conventional Drilling by Karimi Vajargah, The University of Tulsa, et al.

SPE/IADC 163438 Analysis of Potential Bridging Scenarios During Blowout Events by S.M. Wilson, Apache, et al. 

Otto Luiz Alcantara Santos, SPE, is the coordinator of the well-control training and certification program of Petrobras, instructor of deepwater and advanced well-construction technologies at Petrobras University, and a senior technical advisor of Petrobras. He holds a BS degree in civil engineering and an MS degree in petroleum engineering from the Colorado School of Mines and a PhD degree in petroleum engineering from Louisiana State University. He has written several technical papers in well-construction technology, especially on well integrity and directional and horizontal drilling, and he coauthored the book Directional Drilling. Santos is editor of the SPE book Drilling and Production Operations in HPHT Wells. He was an SPE Distinguished Lecturer for 2009–10. Santos is the current chairperson of the SPE Bahia/Sergipe Section and has served on several SPE committees. He is a member of the JPT Editorial Committee.