Proactive well integrity up-keep is an important health, safety, security and environment (HSSE) factor in the industry. Any lapse in well integrity can cause unintentional leaks, which can result in well control situation in terms of safety. This could also lead to aquifer contamination, which is a health and environmental concern. As both subsurface and surface are continuously exposed to deteriorating conditions associated with producing corrosive subterranean fluids from the well and the increasing age of wellstock, the possibility of incidents increases with time. At this point, developing a reliability management system of existing wellbores and wellheads is crucial to ensure optimum HSSE compliance. The objective of such a system is to optimize productivity and add value, by enlisting the causes and the available tools and methods against given well conditions, to ultimately extend the life of the wells, reduce HSSE concerns while reducing operating costs associated with post incident rectification, cleanup and improve reliability.
This paper presents an integrated approach that Saudi Aramco employed to address surface and subsurface well integrity by the incorporation of these types of management systems. In this approach, subsurface integrity issues are addressed through careful well design, continuous monitoring, and re-use of existing wellbores. This approach also provides a wider investigation of surface assets by revealing solutions to surface integrity problems, including unsecured wellheads, leaking wellheads and Christmas trees and limitation of offshore platform design.
To provide a broader insight of well integrity, this paper also focuses on the operational and well intervention phases of a well's life, and discusses evolution of the well integrity management system. The data management processes used to monitor the well integrity system is also discussed.
As Saudi Arabia's oil and gas fields are becoming mature, the well integrity insurance is becoming more important to maintain the wells in a safe condition. Asset safety and integrity are essential elements of Saudi Aramco's corporate vision.
Extensive efforts are being exerted in both the initial well design as well as during operating life of the wells to ensure healthy wells are constructed and maintained. During planning and drilling stages all measures are taken into account, such as covering the corrosive reservoirs with intermediate casings, a proper in-depth casing design which is different for each field and sometime differ in certain area on a field based on experience in drilling neighboring wells, externally coated casing joints across the corrosive water aquifer, ensuring proper casing cementing job to prevent any behind pipe communication, using logs to evaluate and ascertain cement bonds, and finally completing the well with redundant safety equipment, both surface and subsurface i.e. Subsurface safety valve, Surface Safety Valve, Proper Tubing-Casing Fluid with corrosion inhibitors and oxygen scavengers to name few.
