Other Cement LL with DNO

Gomez (2/5-15) – Intermediate section

What happened:

The PAB system failed before the cement job due to water ingress inside the unit which caused some of the automatic dosing valves to fail. The solution was to go back to the “old school” cementing method of pre dosing a pit of drillwater to make the cement mixwater.

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What was planned:

Normal cementing operations use a piece of equipment called a PAB ( Pressurised Additive Booster ). The PAB automatically doses drillwater supplied to the cement unit, turning the drillwater into correctly dosed mixwater.

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What was learned:

The rig used 15 m3 pit #5 and used it to mix 10 m3 of mixwater. 6 m3 required for the job so 10 m3 was made to ensure dead space and line volumes were taken account of. The cement recipe was scaled up from 6 m3 to 10 m3. The water additive chemicals were dispensed into the pit via a hose transfer line. There were three methods used to ensure the correct volume of each additive was correctly added to the pit. 1) The chemical containers had volume gauges on them. 2) The hose from the chemical container to the pit had a flow volume meter on it. 3) The chemical containers were physically dipped with a rod to check volume used.

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What actions are required:

No action required. Good to know that when required the cement mixwater can be generated in a pit.

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What Was Done

Job was carried out safely and successfully. A cement unit mechanic was sent out and fixed the PAB system.