An Innovative Solution to Accurately Address Water Detection in Subsea Wet Gas Conditions and Provide Accurate Condensate Gas Ratio (CGR)

Abstract

In wet gas business, the subsea oil & gas industry are struggling with the fundamental challenges to detect either condensed water or first formation water entry. This need is related to the flow assurance concerns, mitigation process with chemical injection, and detection of water breakthrough but beyond that, there are also challenges of custody transfer, fiscal allocation, and associated biases introduced to measurement devices by the change of fluid properties. In recent years, operators have requested multiphase and wet gas meter manufacturers to solve these challenges by additional measurement and specifically the ‘salinity’ measurement (i.e. conductivity). Most of the manufacturers have responded by incorporating additional sensors into their conventional meter, which address the fundamental problems that their technology faced to correct the bias, but unfortunately, it is also increasing the entire equipment cost. This paper is describing the development of the most innovative standalone solution to obtain this measurement without necessary the need for a subsea multiphase or wet gas meter. This versatility in the installation of the sensor is becoming an enabler for some oil and gas operators that can obtain a very cost effective solution in some development where a meter is not a requirement. The paper is explaining the fundamental principle, and the entire process of qualification encountered over 4 years for obtaining a commercial solution including for high pressure and temperature conditions. The performance of the conductivity measurement will be check against the best flow loop references around the world. The paper demonstrates that even in control conditions with only few tenth to hundredth ppm of liquid (0.001%), it is possible to discriminate the different phases, even the condensate formation inside the pipe (crossing the dew line). This innovative solution is a breakthrough for any wet gas development where flow assurance is critical.