Assessment of Casing and Annular Material in Heavy Mud Weight Systems and Thick Pipes - Case Study

Abstract

Abstract There has been an increased recognition in recent years of the importance of acquiring logs for casing corrosion and annular barrier evaluation for well integrity purposes. It has been a challenge to acquire data in High Pressure and High Temperature (HPHT) environments, where thick pipes and heavy mud weight systems are commonly encountered. In the past, the mud weight had to be decreased or mud changed to evaluate the casing integrity and cement placement, costing extensive time and money. However, recent developments in ultrasonic tools have enabled the acquisition of logs in these difficult environments. This paper describes the logging tool advances for cement evaluation and annular material characterization. It shows, through a case study, how advanced ultrasonic technology enabled the evaluation of the cement and annular material placement for the abandonment operations of an HPHT well in the North Sea. The challenging characteristics of this well are thick casing (0.672in) and heavy mud weight (14.9ppg OBM). A workflow was designed, from planning to execution, to ensure a successful logging job; thereby optimizing the project cost. The log results from advanced ultrasonic technology are discussed and a comparison of the data with the previous generation tool is made. The applied use of data is discussed to plan and optimize the well abandonment program.