A CRI facility combines a surface pressure-containment system with a well-barrier system. The high-pressure pump and surface iron must be managed to their approved design and test basis, while the well-barrier envelopes comprise only the qualified well-barrier elements identified in the approved well-integrity basis. Casing, cement, completion and valve elements provide credited isolation only where their defined acceptance criteria are met and their status is verified.
Define the pressure envelope before operation
The governing envelope must identify the pressure reference point, the active flow path, component ratings, hydrostatic contribution, calculated friction, thermal state and the approved subsurface boundary. Surface pressure, pump discharge pressure and bottomhole pressure are not interchangeable. A maximum allowable value must come from the approved well and geomechanical basis; a generic web value cannot substitute for it.
Map each required well-barrier envelope and its elements
For every credible operating state— injection, displacement, shutdown, bleed-down, maintenance and restart—identify each required well-barrier envelope, the well-barrier elements that form it, their acceptance criteria and how their status is verified. List process safeguards and non-return devices separately unless the approved well-integrity basis explicitly credits them as well-barrier elements. Record which element provides containment and how its status is verified. A closed valve is not evidence of isolation unless its required direction, test status and pressure boundary are known.
Cement and legacy-well uncertainty
Containment depends partly on cement placement and quality across the injection and confining system. Review available cement records, bond or evaluation data where applicable, pressure history and any unresolved loss or channel indication. Offset, legacy and planned penetrations within the regulator-defined area of review and any larger credible modeled influence domain—including uncertainty and upset cases—require screening, because a penetration can become a migration pathway even when the active injector performs normally.
Annulus surveillance is a trend, not a checkbox
Monitor the annulus or annuli specified by the well-integrity program with calibrated instruments and defined observation frequency. Interpret pressure with temperature, trapped-volume behavior, bleed-off or build-up history and valve configuration. A pressure change may reflect thermal expansion, communication, a leaking valve or a barrier failure; classification requires controlled diagnostics, not assumption.
Erosion, corrosion and solids service
CRI slurry is abrasive and may contain chemically aggressive water. High velocities, changes in direction, restrictions, chokes, valve seats and wellhead transitions can localize erosion. Corrosion risk depends on water chemistry, dissolved gases, temperature, metallurgy, oxygen entry and shutdown conditions. Inspection intervals should be risk-based and informed by wall-thickness, leak, solids-quality and operating history—not by calendar alone.
Pressure tests and functional tests
A pressure test demonstrates whether the tested boundary met the stated acceptance criteria for the tested direction, pressure, duration, medium and conditions, within the test method’s sensitivity at that time; it does not establish integrity outside that scope. Record the exact lineup, medium, stabilized temperature, instrument range and resolution, trapped-air control and observed leakage or pressure change. Functional testing of shutdown, relief and non-return devices complements pressure testing; it does not replace it.
Diagnose a suspected leak without escalating risk
Unexpected annulus pressure, inability to hold a test, unexplained pressure-rate behavior, visible leakage or inventory discrepancy requires entry into the approved abnormal-event procedure. Stabilize or stop as authorized, preserve synchronized pressure and rate data, verify the lineup from a safe position and control stored energy before inspection. Do not increase pressure merely to make a weak signal easier to see.
Restart requires evidence and ownership
After maintenance or an integrity event, restart should require closure of the defect, documented tests, restored safeguards, correct valve lineup, available contingency capacity and authorization from the named technical authority. A successful low-rate restart is an observation point, not proof that the original cause has disappeared.
Connected engineering controls
Well integrity must be read with pressure-trend interpretation, formation containment and shutdown governance. These controls share the same pressure references and event chronology.
Barrier and surveillance evidence
| Boundary | Evidence | Do not infer |
|---|---|---|
| Tubular flow path | Current schematic, ratings, pressure test and configuration | That cement is part of the slurry flow path |
| Casing and cement isolation | Approved evaluation and integrity basis | That one log removes every uncertainty |
| Monitored annulus | Calibrated pressure-temperature trend and valve lineup | That zero indicated pressure proves integrity |
| Surface safeguards | Function test and approved barrier classification | That a check valve is automatically a well barrier |
Common questions
Can MAASP be used as the CRI injection-pressure limit?
Not by itself. MAASP is an annulus-specific limit and may be one applicable constraint, including where an annular path is specifically approved. Maximum injection pressure, equipment limits and subsurface-containment limits must be evaluated for the actual flow path, load case and common stated pressure reference; operate within the most restrictive translated approved limit.
Does zero annulus pressure prove integrity?
No. It is one observation. Instrument condition, valve lineup, trapped volume, temperature and the complete barrier evidence still matter.
What is the safest response to an unexplained pressure change?
Follow the approved abnormal-event procedure, control stored energy, preserve synchronized data and obtain authorization before testing or restart.
For suspension, final reconciliation and long-term handover evidence, continue with CRI closure and post-injection monitoring.
