Flow Assurance Technical Section

As a production measurement and allocation specialist I often get asked about various analyzers.  In the early days of the GOM Deepwater (circa 2002), I worked with flow assurance and production chemistry to solve the problem of high methanol concentration in the export pipeline.  I was asked if there was an online analyzer that could be used to monitor the concentration of methanol in the export pipeline.  Unfortunately, at that time there was no such analyzer, which was understandable given that the high concentration of methanol in crude oil and the knock-on effects within the refining sector were pretty new back in 2002.   As a result, we resorted to water washing within the production system to dilute the methanol.  And even then, we brought wells on very slowly just to be safe.  Of course, bringing the wells on slowly results in deferment (cost) and contaminating the midstream system results in very high cost.  Lately, this issue came up again.  So now that the industry is 20 plus years further down the technology journey, I thought I would check in on progress.  Does anyone know of an effective "online" way to measure the concentration of methanol in crude oil streams?

Hi Robert,

We were once confronted with this scenario and the research that i had done led me towards solutions like

• ParaFuel Analyzer system from AMETEK Grabner Instruments ;
• MOD-4100 Crude Analyzer by Modcon Systems Ltd ; and 
• Gas Chromatography- Based Analyzers from many providers just like PerkinElmer.

Just check them see.

Regards.

Hello Robert,

As far as I understand there are a couple of methods that are in use for controlling quality in low levels (less than 10 ppm) of methanol concentration measurements. The Multidimensional Gas Chromotography (MDGC), uses a switching device to isolate methanol from the oil mixture.

"Determination of Low Levels of Methanol in Crude Oils by Multi-dimensional Gas Chromatography (MDGC) Using Novel Micro Channel Flow Technology", Andrew Tiple; Lee Marotta; Frank DiSanz; Heidi Grecksek.

The other technique si the one recommended by the ASTM D7059, also based in chromatography which measurements ranges from 15 to 900 ppm. This designed methodology is well known for its accuracy and reliability. you can check the supporting documents within Scion Instruments web page: ASTM D7059 - Methanol in Crude Oil Analysis.

Both methods can be deployed on-line for real-time monitoring and control in the aim of keeping quality and safety for crude production and processing operation's.

I hope you find this information of some help.

Regards,

José Antonio Rodriguez Pimentel

Petroleum Engineer, SLB-Retiree 

Hi Robert, methanol is "easy" to detect and measure in real-time systems that include a measurement of RF permittivity. We can see it with our MicroSilicon Quantum RF Analyzer, for example.

The challenge with using permittivity is that it can't tell the difference between, say, 5% water and 3% methanol vs 2% water and 11% methanol - both would give the same effective dielectric contribution, so it really depends on what you are hoping to do with that measurement.

Regards, J.