Field Booster Unit Installation
Field Booster Unit Installation
(OP)
I'm looking for someone who has any experience with installing small (1000 hp or less) skid-mounted reciprocating field booster compressors (nat gas service)?
My experience is mainly in large concrete-slab mounted units inside compressor buildings, and I have no practical experience in these cheap, in-the-dirt installations.
I'm probably making a mountain out of a mole-hill, but it's a hole lot more expensive to estimate a mole-hill and end up having to go back and build a mountain.
Some of my main concerns are:
-Settling of the any type of dirt bed (compacted or not)
-Piping strain due to movement due to settling or the skid "walking" around.
I'm specifically interested in what preferred method you may have in setting the unit. Examples:
-Concrete slab & anchor bolts
-Compacted dirt bed(such as caliche), and what materials are preferred for this type of bed.
Any ideas you may have and are willing to share would be appreciated.
Don't post if you have speculative ideas...looking for guys with real experience.
My experience is mainly in large concrete-slab mounted units inside compressor buildings, and I have no practical experience in these cheap, in-the-dirt installations.
I'm probably making a mountain out of a mole-hill, but it's a hole lot more expensive to estimate a mole-hill and end up having to go back and build a mountain.
Some of my main concerns are:
-Settling of the any type of dirt bed (compacted or not)
-Piping strain due to movement due to settling or the skid "walking" around.
I'm specifically interested in what preferred method you may have in setting the unit. Examples:
-Concrete slab & anchor bolts
-Compacted dirt bed(such as caliche), and what materials are preferred for this type of bed.
Any ideas you may have and are willing to share would be appreciated.
Don't post if you have speculative ideas...looking for guys with real experience.





RE: Field Booster Unit Installation
RE: Field Booster Unit Installation
RE: Field Booster Unit Installation
The units we're working on now will be in south and east texas.
I can confirm that the skids will be concrete filled.
So you do not usually install any kind of structure (concete anchor or sleeper) to keep the unit from moving back and forth or twisting?
Another question regarding rainwater: How do you deal with the rain water that collects on skid? Do you use a below ground sump and then pump it to a storage tank, or what other kind of method do use to remove the rainwater...we can't allow it to overflow onto the ground.
RE: Field Booster Unit Installation
Smaller than 1,000 hp there are very few foundation/grout jobs. There are hundreds of CAT 3412 (about 550 hp at this elevation) compressors dropped in the dirt. These also have concrete filled skids.
If you're looking to pay for an answer there are a lot of consultants out there.
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
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RE: Field Booster Unit Installation
However, most of the "consultants" I've worked with or run into are worth less than the Canadian change I have in my pocket.
RE: Field Booster Unit Installation
RE: Field Booster Unit Installation
I've set Cat 3606 (1700HP units on packed caliche. Normally thats just above the size normally set on "gravel". Cat 3516's and Wauk7042's are on gravel. A044 or cat 3520 or cat 3606's are a toss up. By the cat 3608 yeah, they are set on concrete, but no grouting in. A cat 3616, its grouting in time.
NOW a new revelation.... Screw piles, look them up. We aree seeing them used inlieu of concrete pads....
RE: Field Booster Unit Installation
I've used devices that look like the screws you use to shore up a sagging foundation with really good success. Is that what you mean? Again, it takes a well engineered skid, but seems to work really well.
At the other end of the spectrum, we had a site that was built on fill and the first three compressors installed were shaking themselves to death. I spent some time with a Geotech Engineer and he recommended that we excavate down to bedrock (the hole was 20 ft wide, 19 ft deep at the deep end and 9 ft deep at the shallow end) then fill it with "flowable fill". We set a matrix of rebar a couple of feet into the fill, then poured a conventional foundation and grouted the compressor in. The 7042 driving a HOSS compressor never shook at all. Nearly a perfect result.
Bottom line of the story is that a thousand hp is a reasonably big load, and the mass of the cylinders create some interesting moments and couples. Engineering is required (either in the skid and/or in the foundation) to create a way to manage those forces. I wouldn't have a problem setting a Cat3606 or a Waukesha 7044 on a gravel pad if the skid was designed for that service.
Now when we design a skid to be grouted and throw it in the dirt, things don't end well.
If the installation calls for a compacted 2 ft of road base, I'm pouring a foundation. It takes forever to compact a 2 ft thick pad in 6-inch lifts, and it isn't worth it. You can set a portapad cheeper.
David
RE: Field Booster Unit Installation
RE: Field Booster Unit Installation
Soil analysis is another thing. This one is such a rush job, that we can't get a soil guy out there in time to drill, analyze, and report back, before the unit is expected to be inservice, and the PM didn't do any of this ahead of time.
The skid is a vendor's standard, wide-skid, full runner, tall beam, concrete-filled, in the dirt design.
Hopefully, we'll get lucky and everything will be okay...and the PM will go off all proud and all.
RE: Field Booster Unit Installation