Automatic Custody transfer

(ACT)

Most crude oil is sold automatically through Automatic Custody Transfer (ACT) units as follows:

– When the oil level in the run tank rises and triggers a high-level switch, the ACT pump pulls oil from the bottom of the run tank.

– An electrical capacitance probe inserted in the crude stream monitors the S& W content of the liquid being pumped to detect “bad oil“. If S& W contamination rises above the purchaser’s maximum (often 1%), valves are automatically switched to divert the crude stream back through the treating facilities.

– If S& W remains acceptable, the crude volume is measured by an extremely accurate positive-displacement meter that automatically adjusts the recorded volume for temperature expansion or contraction. The meter is equipped with a printer that automatically prints the volume sold on the “run ticket“ that verifies the sale.

– Every few seconds, an automatic sampler extracts a small quantity of the passing crude stream and stores it in a sealed sample container.

– Custody transfer is now complete and the crude enters the purchaser’s pipeline, marine tanker, or other facility.

– Periodically, often once a week, representatives of the producer and the purchaser meet at the ACT unit to process the accumulated sample.

– The sample is thoroughly mixed and a test-tube full is “ shaken-out “ in a centrifuge to determine the percent of S& W it contains. The S& W volume will be deducted before payment is made. Another portion of the sample is tested with a hydrometer to determine the crude’s API gravity.

– The S& W and gravity data, witnessed by both parties, is entered on the run ticket, which already has the metered volume printed on it. The run ticket is then the basis for payment.

– Every few months, the meter is “ proved “ by installing a highly calibrated check meter in series with it. Crude is pumped through both meters and the quantities they each record are then used to calculate the meter factor that is used to adjust the metered volumes until the next proving.

To review, the following data is required to transfer custody of crude oil

– Volume

– Temperature

– S& W content

– API gravity

7.2 Comprehension questions:

1 What is ACT?

2 How is “ bad oil ” detected?

3 How is the crude measured?

4 When does the crude enter the pipeline?

5 What do the representatives of the producer and the purchaser meet at the ACT unit for?

6 What is the basis for payment?

7.3 Give Ukrainian correspondences:

positive displacement meter; “ run ticket ”; treating facilities; crude stream; “ shaken-out ”; gravity; volume; a test- tube; run tank.

7.4 Make 3 sentences using the above mentioned words.

7.5 Match the pairs:

oil stream

crude container

sample factor

gravity level

meter data

7.6 Make interrogative and negative sentences:

1 The ACT pump pulls oil from the bottom of the run tank.

2 The crude stream is diverted back through the treating facilities.

3 The positive-displacement meter automatically adjusts the recorded volume for temperature expansion or contraction.

7.7 Try to explain why crude oil cannot be used as a fuel itself.

7.8 Retell Text 7

8.1 Read and translate Text 8

Text 8