CRI troubleshooting should begin by locating the change before naming the failure. Rising pressure can originate in the surface line, injection string, perforations/near-wellbore region or receiving formation. Poor slurry can be the cause, a consequence, or unrelated. The safest and fastest workflow is therefore evidence-led: verify measurements, compare operating conditions, isolate a hydraulic segment only when authorized personnel can do so under the approved procedure, including required isolation, lockout/tagout, bleed-down and zero-energy verification without breaking containment, and escalate subsurface concerns through the approved assurance process.
This control belongs to a connected operating system. Use the CRI engineering pillar, the integrated surface process and formation capacity and containment together; changing one boundary can move the constraint elsewhere.
Step 1 — verify the signal
Confirm pressure and rate measurements, valve lineup, pump condition, tank level, slurry batch and recent operational changes. A bad transmitter or configuration change can mimic a developing restriction.
Step 2 — compare like with like
Compare pressure at similar rate and slurry condition. Check whether density, PSD, rheology, carrier fluid, temperature or batch source changed. Raw pressure comparison across different rates is weak evidence.
| Observed pattern | Evidence to check first | Possible direction—not a final diagnosis |
|---|---|---|
| Pressure up, rate down | Gauge validity, valve lineup, slurry batch, surface restrictions | Hydraulic restriction or changing injection response |
| PSD off project requirement | Sample method, feed, grinder/screen condition and recirculation | Preparation-system control problem |
| Tank settling / unstable batch | Agitation, residence time and slurry QA/QC | Slurry homogeneity / suspension problem |
| Volume mismatch | Tank levels, meters, transfers, flushes and time basis | Measurement/accounting issue or unrecorded movement |
Step 3 — look for surface restriction
Review de-trashing, grinder performance, strainers/screens where fitted, valves, hoses, bends and flush behavior. A restriction upstream of the well can raise surface pressure without any change in formation acceptance.
Step 4 — examine settling and shutdown history
Extended static periods, inadequate mixing or incomplete flushing can allow solids to settle. The location depends on geometry and velocity history. Do not force pressure through a suspected plug outside the approved procedure.
Step 5 — correlate with slurry QA/QC
Collect samples only from a designated, depressurized sampling point under the approved procedure. Do not loosen fittings, open pressurized containment or reach into moving equipment to obtain a sample; use the required PPE and exposure controls.
Retain and compare representative samples when possible. A coarse tail, foreign debris or unexpected solids loading can support a slurry-related hypothesis, but a single sample may not represent the material already in the well.
Step 6 — recognize subsurface escalation
If surface causes are not supported and the pressure-rate response has changed materially, involve the responsible subsurface/well-integrity team. Published CRI programs use injectivity tests, pressure analysis, temperature information and model updates for this purpose.
Do not troubleshoot by increasing limits
Changing an alarm, maximum pressure or pump setting to keep injecting is not troubleshooting. Limits belong to the approved design. A worsening trend should trigger diagnosis and the defined contingency, not normalization of the abnormal condition.
Symptom matrix: pressure up, rate down
If pressure rises while achievable rate falls, verify pump condition and suction first, then valve lineup and surface restrictions, then slurry changes and shutdown history. If surface evidence does not explain the change, escalate for well/subsurface assessment. The sequence is designed to eliminate accessible causes without assuming the formation is at fault.
Symptom matrix: PSD off specification
Check sample representativeness, de-trashing/screen condition, grinder wear/configuration, feed lithology and recirculation. Do not compensate indefinitely by reducing fresh-feed rate without understanding whether the root cause is wear, overload or a changed waste stream.
Symptom matrix: tank settling
Verify agitation, operating level, batch hold time and slurry properties. Inspect for dead zones where safe. Settling in a tank warns that static sections of the hydraulic path may be at risk too, but it does not prove that a line or well is plugged.
Symptom matrix: volume does not reconcile
Check tank gauging, meter totals, flush and carrier-fluid accounting, transfers, manual entries and unit conversions. A mass-balance discrepancy is first a data-quality problem to investigate; do not label it an environmental loss without evidence.
Close the loop after recovery
After restoring operation, record what changed and verify the expected indicator recovered. If cleaning a line reduced pressure at comparable rate, that supports a restriction hypothesis. If pressure remains abnormal, the original diagnosis was incomplete. Troubleshooting is not finished when equipment starts-it is finished when the evidence matches the explanation.
The key question is not “why is pressure high?” but “where did the system response change, and what evidence separates the possible causes?” That framing prevents expensive and potentially unsafe guesswork.
Common questions
What should be checked first when CRI pressure rises?
Verify instruments, rate, valve/configuration status, pump condition and slurry batch before assigning the problem to the formation.
Can poor grinding cause loss of injectivity?
Off-spec solids can contribute to restrictions, but the diagnosis requires evidence because surface, wellbore and formation mechanisms can produce similar symptoms.
Should operators increase the pressure limit to clear a suspected plug?
No. Follow the approved project procedure and pressure limits; do not improvise by raising safety or integrity limits.
