Being "the authority" on wellhead compression really doesn't mean much--engineers have been avoiding that horrible subject for nearly 100 years. Most wellhead compressors I see were designed for a traditional plant or pipeline application and then pulled off of a surplus list to supply a field foreman with some hp (e.g., "this application is 3 compression ratios, so you obviously need this 3-stage recip compressor that I've got in my back yard").
P&ID's are typically proprietary to the packager or (rarely) to the purchaser. I've done a few for clients, but the client owns them at the end of the job. There really isn't any such thing as a "standard P&ID". I've been thinking about writing something for Pipeline & Gas Journal about screws that might include a simplified schematic, but I don't know when (if ever) I'll find the space in my schedule to do that.
When you're evaluating designs of flooded screws, the absolute key is oil. Flooded screws have only been around for 30 years or so and they spent the first 20 years almost exclusively inside plants (either as air conditioning units or air compressors). In virtually all plant applications, the conditions are very well defined (e.g., the gas might be dehydrated so oil temp is a secondary consideration, or the machine will always have a 50 psi dP so an oil pump is not required). For wellhead use, an oil pump is always required. If anyone tells you differently then RUN AWAY from them.
As I've said many times in this forum, compressor oil is hydrophilic and would make a very good dehydration media if it wasn't so expensive. You must get the oil hot enough to cook the water out of it or the oil performance will rapidly degrade (i.e., the surface tension will increase which allows progressively larger droplets to avoid coalescence, lubricity will degrade, and viscosity will increase). The typical plant approach of using a 3-way valve to manage oil temp into the start of the oil system is evaluating the wrong thing and is only effective at exactly one set of operating conditions. I like to use a secondary cooling loop that has a temp sensor at the outlet of the screw and manages secondary cooling loop flow to keep that temperature constant. If you can cook off water, the oil will last indefinitely and becomes very inexpensive.
David
