Selected work/Produced water balance
Seven water streams tracked separately at each facility, disposal headroom taken at actual injection pressure, and the oil effect of each water limit stated.
Outcome
Objective met4 of 4 success criteria. Read the conclusionThe field produced water at rates close to its oil. Disposal into a shallow formation, re-injection for pressure support and evaporation ponds each had their own capacity, availability and reliability. Operating plans treated water capacity as one number. An earlier terms of reference had listed the known problems: interface control in the dehydrators, oil-in-water measurement, meter coverage, installed pump capacity, single-pump stability, and oil recovery from the ponds and drains.
We built the balance for each facility from the daily water summaries, the well tests and the pump logs. Seven streams were carried separately: water separated by train; water treated or transferred to disposal; water injected into disposal wells; water re-injected; water sent to ponds; oil-in-water excursions and recycled oil; and pump outages and disposal pressure. Disposal headroom was taken from the injection wells at their actual wellhead pressure, not from nameplate. A 2020 investment paper's requirement for 23 disposal wells was broken down into 11 for added capacity, 7 for N+1 cover and 5 replacements, and carried as a dated planning basis.
Each water limit was then written against its upstream effect: the wells, by facility, that would be cut back if a transfer pump tripped or an injection well lost injectivity.
Where the water goes
Produced water routes on a water-flooded field. Each route has its own capacity, pressure and way to fail.
Conceptual, not for constructionThe operator's optimisation cases were tested against the water routes they would load, not against one water number. The evaporation route was shown as its own stream so it was never counted as disposal.
The objective was a water balance the operator could test its optimisation cases against, with disposal headroom stated at real pressure. It was achieved. The balance closes by facility with the error shown, the headroom table carries a pressure and a date for every injection well, and two routing cases were withdrawn because the balance showed the disposal pumps could not take the water.
| Success criterion | Met | How it was achieved |
|---|---|---|
| iWater balance closes at each facility between separated, treated, disposed, re-injected and ponded water | Met | Balance issued by facility with the closing error shown, and refreshed weekly from the daily summaries |
| iiDisposal headroom stated at actual pressure, with the date of the pressure reading | Met | Headroom table issued with pressure, date and source for every injection well |
| iiiEvery optimisation case checked against the water route it loads | Met | Two routing cases withdrawn when the balance showed the disposal pumps could not take the water |
| ivEach water limit carries the oil that depends on it | Met | Limit-to-production table adopted in the operator's weekly capacity review |
Deliverables
Evidence note
Work done for the operator of an onshore field in the Middle East. Historic documents (a 2019 scheme, a 2020 terms of reference, a 2020 investment paper) were used as dated engineering context, not as current facts. Operator and facilities not named.
A flowline replacement programme brought from five workbooks into one record per well: risk, service test, replacement scope, construction and handover, planned against actual.
Met4 of 4 success criteriaOperator engagementRead the caseMiddle East·Producing field, flow assuranceA written workflow from pressure trend to field confirmation to targeted treatment to post-job review, adopted as the operator's surface scale identification procedure.
Met4 of 4 success criteriaOperator engagementRead the caseSend us the version you are dealing with. We will tell you what we would do first.
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