Patent ID: 8720573

Claim:
A method for discontinuous use of a permanently installed system for subsea sampling and analysis for determining salinity of produced water from a single subsea well, the method comprising the steps of: integrating the system into a replaceable equipment module for a choke valve for subsea production systems, the system comprising an analysis circuit with a separation-and analysis receptacle equipped with an electrostatic coalescer and two instruments for measuring salinity of separated water, the instruments of which are placed in a restricted lower part of the separation-and-analysis receptacle; filling the analysis circuit from a well flow by opening gate valves and allowing a differential pressure across the choke valve, as measured with a differential-pressure transmitter, to set up and direct a part of the well flow into the analysis circuit, thereby filling the separation- and-analysis receptacle with a representative sample from the production of the well; separating the representative sample in the separation-and-analysis receptacle into fractions of condensate, crude oil and water using the electrostatic coalescer; measuring the salinity of the separated water using the instruments and transmitting these data to a point above the water surface via electronic communication; and upon having completed the measurement of the salinity, circulating hydrocarbons and water out of the separation-and-analysis receptacle and replacing them with Mono Ethylene Glycol, which is termed MEG.