Well integrity/control

Study Sheds Light on Optimization of Well-Diagnostics Investigation

This paper defines conditions for optimized well-diagnostics investigation and describes a rigless solutions for common well-barrier failures and lessons learned from operator field trials.

Bismuth beads and resulting bismuth plug.
Fig. 1—Bismuth beads and resulting bismuth plug.
Source: SPE 216484.

The complete paper defines the conditions for optimized well-diagnostics investigation, allowing preservation of resources and minimization of response time to well failure. It also describes a rigless solutions for common well-barrier failures and lessons learned from the operator’s field trials. This information is valuable for companies aiming to optimize their sustained annulus pressure (SAP) well-management process. The main objective of the paper is to identify scenarios in which the failed barrier element can be recognized from surface data alone.

SAP Management

Well-diagnostic activities can be divided into two classifications: surface activities and subsurface activities (well interventions). Common surface investigation activities include the following:

  • Bleedoff/buildup test
  • Sampling and analysis of the effluent
  • Wellhead seal test
  • Revision of well history
  • Leak-rate measurements
  • Echometer surveys
  • Pressure tests
  • Tracers

Subsurface well diagnostics may include the following:

  • Pressure and temperature surveys
  • Corrosion logs
  • Leak-detection logs
  • Mechanical communication tests
  • Fiber-optic surveys
  • Various slickline tools
  • Installation of downhole gauges

Root Cause Analysis (RCA) of Premature Well-Barrier Failures

For wells with premature integrity failures (when the failure occurs within 10 years of the last rig entry), a new RCA process was implemented.

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