Well Integrity Diagnosis in an Aging Onshore Field Using Modern Diagnostic Tools to Remediate Risk & Inform Completion Strategy
Authors: Snasiri Fatemah Akbar Abas , Roy Alistair , Biery Michael , Jalan Shiv , Landi Nancy , Ali Yousif , Nguyen Bien , Duong Lea , Aparicio Ciro 
Published: November 2024

A Middle East Operator has extensive ongoing well integrity remediation programs in an aging field with significant remaining reserves. Modern diagnostic tools are utilized to improve understanding of considerable well integrity issues. Subsequently, effective remediation reduces risk which allows wells over 50 years old to continue safe production to improve recovery. Well Integrity challenges included: High Pressure, 18 pounds per gallon (ppg) formations interspersed with depleted horizons (9ppg)High H2S & CO2 content.Compromised surface well equipment integrity due to severe damage.Poor zonal isolation leading to downhole fluid communication and ultimately resulting in casing corrosion.Managing learnings resulting from sub-optimal choices in early well construction and metallurgy selection, cementing and logging practices.

Two Case studies will be presented which will demonstrate that focused application of modern technology well integrity diagnostic tools results in successful remediation of complex problems: Diagnosis and Remediation of a 1986 vintage well (Well X). A loss of pressure containment and subsequent hydrocarbon release in 2021 prompted the deployment of a well integrity logging suite including a novel telemetry system. This successfully allowed: Detection of multiple tubing leak points and reservoir fluid communication paths from tubing to annuli ‘E’ to ‘F’, and to the atmosphereIdentification of sources of downhole gas migrationCorrection and update of well records from 1986 and post-war remediationDevelopment of coiled tubing program to isolate High Pressure (HP) permeable zones and facilitate well workover/abandonment.Logging in electrically "noisy" environmentReal Time diagnostic logging and remediation to convert an uneconomic deep exploration well to production service by recompleting two shallower horizons (Well Y). Well integrity logs were performed to diagnose & remediate poor zonal isolation of high-pressure zones in two outer annuli. Diagnostic sensor suite included highly sensitive hydrophone array for flow detection, frequency domain corrosion tool to determine condition of multiple casing strings, circumferential scanning ultrasonic cement evaluation tool, and a through-tubing pulse neutron technology to detect gas migration. These sensors were deployed in several runs during the workover for planning and subsequent confirmation of successful remediation. The operation was successful, and the well is producing normally.

Novel approaches and applications of technology to these well integrity issues included: Real time Well Integrity diagnostics and remediation to convert an exploration well to a producer.Preliminary trial to extend electromagnetic casing corrosion monitoring from existing 5 string capability to 7 strings.Improved telemetry system to allow logging in "noisy" electrical environments.Use of Well Integrity logging suite to infer/determine missing well construction data to design an appropriate safe well remediation program.