HydraCHEK®

When hydrates form they exclude salts and thermodynamic inhibitors such as MEG and Methanol from their structures. If an increase in the concentration of salts or hydrate inhibitor is detected it could therefore be an indication that hydrate formation is taking place.

As described in the SPE paper (SPE166596), Total has used this technique to operate inside the hydrate stability zone, controlling the concentration of hydrate slurry allowing them to extend the life of the NUGGETS field.

Produced water consists of condensed water and formation water. Condensed water is the water present in the gas phase at reservoir conditions and is produced as a gas from the reservoir. At some point condensation of the water takes place due to changes in pressure and temperature conditions but the salinity of condensed water is normally very low.

Formation water on the other hand is the water which leaves the reservoir as a liquid and does contain salt. Production of saline formation water can have a number of issues associated with it, including; corrosion, water handling capacity, slugging, salt formation, etc. Therefore, it is important to detect formation water production and consider potential techniques to minimise its production as early as possible.

HydraCHEK can determine the concentration of salt in produced water and can be used to detect formation water production.

HydraCHEK can measure the concentration of both lean and rich methanol or MEG streams before and after regeneration units or gas dehydration processing and can therefore be used to monitor the efficiency and performance of regeneration units.

Multi-Phase Flow Meters (MPFM) generally measure two physical properties of the produced mixture. Knowing the relevant physical properties of individual phases (i.e., gas, oil and water) using a combination of experimental measurements and predictions, together with material balance, will enable the calculation of the rate of individual phases. The presence of both salt and hydrate inhibitors can change the physical properties of the water phase, resulting in erroneous readings.

HydraCHEK can provide independent information on the amount of salt and hydrate inhibitor in the water and be used to adjust the properties of the water phase helping to improve the accuracy of MPFM readings.

The concentration of contaminates in the water for disposal is an important factor for avoiding further problems downstream (e.g., in produced water re-injection).

HydraCHEK can measure the concentration of selected impurities and/or simply changes in the properties of the liquid phase to minimise associated problems.

In some fields, there is no accurate way of determining the rate or quantity of water being produced. HydraCHEK measures the amount of salt and hydrate inhibitor in the produced water and if the rate of hydrate inhibitor injection and the concentration of the hydrate inhibitor in the produced water are known it will enable the operator to back-calculate the rate of water production.

This could be of particular interest in wet gas conditions where the amount of produced water is too low for accurate measurement by Multi-Phase Flow Meters (MPFM).