RE: Re-re the RNS this morning16 May 2025 06:51
The "siting" of gas casing refers to the time it takes for the cement behind the casing to properly set and harden, which can take 6 to 12 hours. During this time, pressure can be held on the inside of the casing to prevent it from collapsing due to the heat generated by the setting cement, especially with PVC casing.
Here's a more detailed explanation:
Cement Setting:
When cement is pumped behind the casing, it undergoes a chemical reaction that releases heat and causes it to harden.
PVC Casing:
PVC casing, often used in shallow wells, can be weaker and more susceptible to collapsing under the heat generated by the setting cement.
Pressure Holding:
To prevent the casing from collapsing, a pressure can be applied on the inside of the casing until the cement has fully set. This is usually achieved by using a "tremie line," a pipe inserted into the well, to maintain pressure.
Timeframe:
Generally, 6 to 12 hours is sufficient for the cement to set and allow the pressure to be relieved, according to a Driller article.