Has anyone ever heard of a driller using bags of cement to line the bore hole by hand, instead of trucking the cement in?
It is tough to get a guy with a trowel down the hole.
No, I have never heard of a driller using bags of cement to line the bore hole by hand.
My buddy lives by a well and keeps asking when they will bring the cement trucks in, after seeing many pallets of bags of cement. The guard told him they are cementing this one by hand. That didn't sound right so I thought I'd ask here.
Back in the day, the derrickman would be assigned to cut cement sacks to feed the cement blender, much the same as his job to cut mud chemical sacks for the mud system.
I'm not aware of anyone cementing wells by hand, unless it would be to grout in an uncemented upper portion of a surface casing string, known as a " top job" in the business. I've not seen this done by hand, but I have seen it done by pumping through very small diameter tuning or open ended small diameter drill pipe, depending upon the system. The design of the wellhead system would dictate access method to any uncemented annuli.
Thank you, Brian Powers, for your thoughtful reply. I have leased land, but am no expert. It's nice to come here and get good comments that are from professionals.
Frank - You're very welcome, indeed. My oil and gas expertise is mainly in the production and petroleum engineering fields, with some reservoir and extensive well completions engineering expertise also . I've sat through hundreds of meetings and conference calls related to drilling, casing running and cementing problems, so my opinions now and in the future on this site will remain grounded within my main ares of experience and exposure.
Brian, you better be careful, we'll be inviting you to do seminars for us!!! Thanks Brian, you're a wealth of information!!
could be hand troweling to keep the trolls down there
not trolls.............skinny chinamen!
I talked to a guy whose companies does well casings. He told me they have high quality standards for the cement they use and only use product brought in just for well casing. They barge dry goods up the river and mix the cement on site.They don't use local cement yards to truck it in.
They also use a special mix that keeps the water in the mix. When you finish regular concrete the water will rise to the top. If you get a seam of water along the well casing or along the edge of the drilled hole, that seam can become a pathway for gas to travel.
They also use a lot of additives like hardeners, adhesives, and things to resist cracking. And additives to promote expansion to fill all voids. Like all things in the industry, more complex science than we would expect.
Thanks all. This is all very interesting. I love learning new things and I'm at the right place for it.
You are correct in that oilfield cement is very different than construction concrete. For starters, oil field cement contains no aggregate (sand or gravel). As you indicated, loads of additives (often very expensive and a great profit margin generator for the pumping companies are available to add strength, accelerate or retard the set time, alter the pumpability, etc.
You are also correct when you state that free water is the enemy of well casing cement, as it can create channel voids or pathways for unwanted gas migration. These channels are tough to detect and can be expensive to repair.
In offshore oil and gas operations, the cement is brought to location in large vessels and in powder form (the cement is ground to extremely fine particle size as dictated by American Petroleum Institute, or API, standards). The dry cement is "blown" from the boat to large hopper tanks on the rig near the cementing unit and kept dry until mixed and pumped. Many of the additives are included in liquid form, which eases handling and reduces exposure to the cementing crews.
Samples are mixed in advance and are generally supplied to the Company Man to ensure the cement sets properly (a set in a sample container or paper cup does not ensure adequate generation of compressive strength, though, these tests are run well in advance of ordering the product, equipment and crews to location). Various integrity testing or cement evaluation methods are available to ensure that the cement is working per design before the next phase of drilling commences.
Brian; Thanks for helping me understand well casing better. It is the most critical part of the entire gas production process and the one that we understand the least. Here's another aspect I wonder about.....how do they keep the the casing centered in the well bore while they are cementing it? Seems it be very easy for the casing to shift and leave thin spots or even sections with no cement if the casing were to shift up against the well bore wall.
Also, I had been wanting to thank you earlier for all your posts. They have been very helpful in helping us better understand the industry we will be working and living with for the next several generations. Not only will this info helps better understand the risks and rewards but will also help us fight back against the anti folks and their habit of using selective data and/or misrepresenting the facts. Thanks.