WorkflowPipelines, Midstream & LNG

Custody Transfer Measurement Audit

Custody transfer measurement checked against the contract that governs it, with every miss priced day by day before the statement is released.

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Follow one chromatograph error from 09:40 to the notice ↓

The problem

The lab sample disagreed with the chromatograph, and it went into a folder

Flow computers keep their audit records, technicians file verification reports and photos, chromatographs keep their calibration reports in their own software, and lab results arrive by email. The contract sits in another system again. Each month the analyst validates volumes by exception and checks the paper by sampling, if at all.

When something is found, the correction is worked in a spreadsheet, the letter to the other side is written by hand, and the edit gets keyed into the measurement system. A missed notice lets the other side ask for the test again, and a correction worked over the wrong days is a dispute waiting to happen.

Built forMeasurement analystsMeasurement leadsField meter techniciansGas contracts managersInternal auditors

The Problem Today

Money moves on the meter, and the proof sits in logs, certificates, lab reports and forms nobody reads together.

527 h: a month to check one month's records by hand, at 2 minutes each our estimate
$32,000: a month for each 0.1% heating value error at one busy station our estimate

Checked by hand today

Meter logs
Calibration
Lab reports
Witnessing

A report filed, not comparedThe lab sample was right, and it sat in a folder
Missed notices undo testsWithout due notice, the other side can ask again

The Solution

Reads each recordFlow computer exports, calibrations, certificates, lab reports and forms
Draws the stationEach part marked with its last check and the clause that governs it
Puts a dollar on a missPeriod, clause, volume, energy and money, day by day, with the sums shown
Signed before it leavesThe lead signs, the contracts manager countersigns and sends the notice

Built-in controls

Lead opens each record before signing
Agents never sign, send or post
Figures post through your measurement system

What You Get

Measurement teams settle each miss on the contract's own terms, before the bill goes out.

A file per station and monthWhat is on file, what is missing, what blocks it
Missed notices caughtEach one with the test it puts at risk
The largest number has two ownersAbove a set amount, the contracts manager countersigns

One station, one morning

Custody transfer measurement at a plant tailgate, from drawing to notice

A sales gas station at a plant tailgate read its heating value high for weeks, and the month's statement has not gone out yet. Here is the morning that prices the error and puts it in front of the buyer, on the working screens.

demoThe station, both companies, the contract wording and every figure here are sample data.

0109:40
Three duty runs, a check meter, and a chromatograph 0.6% high
Measurement analyst
The station opens as it is built: filter separator, three ultrasonic duty runs, a check meter on the header, the flow computer, the chromatograph with its calibration standard and heater. Each part carries its last check. Under the drawing, the heating value strip shows this station stepping up while the station downstream on the same gas stays flat.
0209:40
A cabinet heater tripped before a 19 °F night, with no alarm
Measurement analyst
Opening the analyzer cabinet heater shows the station event log: the heater fault, a 19 °F night, and the automatic calibration that ran the next morning. The agents offer this as the likely cause, for a person to confirm: the calibration gas went short of heavy components in the cold. The expired certificate the technician found moved no reading.
0309:40
The lab read 1,036.7, and nobody set it beside the chromatograph
Measurement analyst
The spot sample point is marked never compared. Its lab report, emailed to the measurement mailbox, read 1,036.7 Btu per cubic foot while the chromatograph was reporting 1,043.0. It was filed. A person found the fault later, and the first agent cycle priced it. From here on, each report is compared when it arrives.
0409:43
17 gas days, known definitely, so the fallback clause does not apply
Measurement analyst
Across 31 daily calibration reports, the heavy-component factors stepped down at one calibration and came back when the standard was replaced; the meters' speed of sound and the downstream station agree on the same days. The tolerance clause allows 0.5% and the error is 0.60%, so the correction clause applies to the known period.
0509:43
Each gas day is a row, and the rows add to 44,611 MMBtu
Measurement analyst
Read volume, read and true heating value, and the overstatement, day by day. At the sample contract price of $3.00 that is $133,833 off a bill not yet sent. The screen also shows the fallback, half the days since the last check: 14 days, $110,319. Nothing posts from here, and the statement stays held.
0609:49
Hexanes plus fell 79.0% at one calibration, and no alarm sounded
Measurement lead
The analyst sends the working to the lead, and nothing reaches the buyer. Before she can sign she must open four records herself. The first is the calibration report: the response factor changes against the day before, and an alarm window of plus or minus 100% that let them through. That window is a finding of its own.
0710:01
Four records opened, then her signature on $133,833
Measurement lead
She opens the standard's certificate, the correction clause and the day-by-day working, and her own opening is what counts. Then she signs. The chain across the top moves to countersigned, with the contracts manager, because the amount is above $50,000. A send-back would clear her openings and need a reason.
0810:04
The contracts manager reads the correction clause in its own words
Gas contracts manager
Clause 9.4 is quoted, never paraphrased: correct to zero error for the period known definitely, otherwise half the time since the last check. The contracts manager opens it and the working before the countersign button turns on. Unclear wording comes to this desk, never to an agent.
0910:13
Notice sent with the working, and the statement still held
Gas contracts manager
Countersigned at 10:10, the notice of correction goes to the buyer with the working attached, inside the contract's notice clock. Sent notices are frozen by version. The buyer's measurement representative, who witnessed the tests on the old cylinder, now has it. The lead decides and posts only after that reply.

Prior period adjustment: 44,611 MMBtu from two causes, one price

A heavier reading raises heating value and, through compressibility, volume too. The volume share is the agents' estimate, and the measurement system's own re-run decides it.

From heating value, 1,043.0 read against 1,036.8 true	36,161
From volume, 5,832.7 MMscf read against 5,824.6 true	8,450
Overstated, MMBtu	44,611
At $3.00, the sample contract price	$133,833

demoSample data, from the working solution.

Five corrections in the month, and the chromatograph is the largest

Each one worked on its own contract's clause. Only the chromatograph case is built out in full in the working solution.

Station fault	Period	Amount
Chromatograph read heating value 0.6% high	17 gas days, known	$133,833
Ultrasonic path failed, meter read 0.24% low	9 gas days	$41,199, in dispute
Orifice plate found bent	Unknown: half of 77 days, capped at 30	$18,582
New flow computer set to 14.65 psia base, contract 14.73	14 gas days, known	$9,876 credit
Temperature transmitter read 1.8 °F high	Unknown: half of 30 days	$6,414

demoSample data, from the working solution. $209,904 gross across the five.

Across the fleet

Findings, lots, station files and witness notices behind the meter

Beyond the one station, the measurement team's other queues, any of them opened large with a click.

October findings queue: 214 findings across the fleet by kind, station, owner, clock and state — **October findings**214 findings from 15,818 records, by kind, each with an owner and a clock. Late spot samples lead at 46, then 41 missed witness notices.

Lot of 43 late lab samples with 8 drawn by the system for the lead to judge, none judged yet — **A lot, judged by sample**43 late lab samples with no correction proposed. The system draws 8 for the lead to open one by one, and any failure returns the lot.

Audit file for one station and month: required records found, six blocking items, and the complete mark unavailable — **The station-month file**What the contract and the standard ask to have on file, and what blocks it. Six items stand open here, so nobody can mark it complete.

Witness register for one station: tests with notice sent, hours of notice, attendance and form, one marked notice short — **Witness register**Each manual test against the time its notice went out. One transmitter check had 24 hours where the contract asks 48, so it needs a re-test or a written waiver.

Gas sales agreement measurement articles with what the agents check against each clause, and other contracts' terms — **The measurement articles**The contract's measuring, notice, tolerance and correction clauses, each with what is checked against it, beside the terms of the other contracts.

Audit trail of the adjustment: records opened by the lead and contracts manager, signature, countersignature and the notice sent — **Audit trail**Who opened which record, minute by minute: the lead's four, the contracts manager's two, both signatures and notice version one as sent.

demoSample data, from the working solution.

Who prepares a correction, who signs it, and who tells the buyer

Nobody checks their own work, and nothing reaches the other side before both signatures.

Measurement analyst

Sees: The station drawing, the findings queue and the agents' working
Signs: Nothing: prepares the correction and sends it to the lead

Measurement lead

Sees: The calibration report, the certificate, the clause and the day-by-day working, each opened by her
Signs: Signs corrections and lots, then decides and posts after the buyer's reply

Gas contracts manager

Sees: The clause and the working, opened again
Signs: Countersigns above the set amount, sends the notice and rules on disputes

Field meter technician

Sees: Checks due by station, with the notice date each one needs
Signs: Runs and records the tests, which the lead then checks

Internal auditor

Sees: Who agreed the largest number, and what each person opened
Signs: No signature: reads each record and keeps an evidence export

The agents

Eight agents read the meter paper, and none of them posts a figure

Each reads or works one part. People sign, send and post.

Record reader

Reads audit exports, verification and calibration reports, certificates, lab reports and witness forms.

Leaves each source record untouched
Holds an unreadable page rather than guessing it

Station checker

Checks each part against its schedule, certificate dates and tolerances.

Never decides a correction

Gas analysis checker

Compares chromatograph, lab sample and stations on the same gas.

Never rules on cause; says likely, and why

Clause finder

Finds the governing clause and quotes it with its place.

Never interprets beyond the words

Adjustment calculator

Works out period, branch, corrected values and money, day by day.

Never posts; figures go through the measurement system's import

Witness tracker

Tracks notices, attendance and missed notices, and what each blocks.

Never waives a counterparty's right

Notice drafter

Drafts the correction notice with the working attached.

Never sends

Audit file builder

Builds the station-month file and its evidence export.

Never marks a file complete with a blocking item

What measurement leads ask about a custody transfer measurement audit

What is a custody transfer measurement audit?

A custody transfer measurement audit checks that the meter records, calibrations, lab samples and witness forms behind a gas bill meet the contract. Here agents read those records for each station-month, tie each check to its clause and price any miss, and the measurement lead and contracts manager sign before anything reaches the other side.

How is the period of a correction decided?

From the evidence, where it exists: daily calibration reports, the meters' own diagnostics, a station downstream on the same gas and the lab sample. If the period cannot be known, the contract's fallback branch applies, and the working shows both so anyone can see why one was chosen.

Does this replace our measurement system or EFM audit tools?

No. Corrected figures go through your measurement system as a prior-period edit, and its own re-run must match the working before the statement is released. The agents read flow computer exports alongside the paper those tools do not hold: certificates, lab reports, witness forms and the contract.

What happens in a gas measurement dispute?

The contracts manager rules and writes down why. That ruling is your position, not a settlement. A revised figure goes to the other side as a new version of the notice, and earlier versions stay as they were sent.

Can the chromatograph's cause of error be trusted?

The agents say likely, and why, and cite each record behind it. A person confirms the cause. The money does not depend on it: the correction rests on the period the calibration reports show and on the contract's clause.

Whose contract terms are used?

Each contract's own. Tolerances, notice periods, correction branches and caps are read from the agreement, never typed into settings, because they differ from one contract to the next. Industry standards are licensed, so your team loads its own copies.

Pipelines, Midstream & LNG

Bring one station-month
and the contract behind it.

We’ll tie its checks to the clauses and show what a missed comparison would have cost.

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Custody Transfer Measurement Audit

The lab sample disagreed with the chromatograph, and it went into a folder

The Problem Today

The Solution

What You Get

Custody transfer measurement at a plant tailgate, from drawing to notice

Three duty runs, a check meter, and a chromatograph 0.6% high

A cabinet heater tripped before a 19 °F night, with no alarm

The lab read 1,036.7, and nobody set it beside the chromatograph

17 gas days, known definitely, so the fallback clause does not apply

Each gas day is a row, and the rows add to 44,611 MMBtu

Hexanes plus fell 79.0% at one calibration, and no alarm sounded

Four records opened, then her signature on $133,833

The contracts manager reads the correction clause in its own words

Notice sent with the working, and the statement still held