Level and Pressure Control in Oil and Gas Production

When production is mainly gas, and remaining liquid droplets have to be separated out, the two-phase separator can be a knockout drum (K.O. drum) to separate the gas and liquid phases.

The coalescer unit is used for final removal of water from the oil, reducing the water content to below 0.1%.

The coalescer is filled with liquid, with water at the bottom and oil on top. Internal electrodes form an electric field to break surface bonds between the conductive water and isolating oil in the oil-water emulsion.

<p>If the separated oil contains unacceptable amounts of salts, such as sodium, calcium or magnesium chlorides, they can be removed in an electrostatic desalter.</p> Signup and view all the answers

<p>The desalters will be placed after the first or second stage separator depending on the gas-to-oil ratio (GOR) and water cut.</p> Signup and view all the answers

<p>On an installation with a high water cut, there will be a huge amount of water produced, making water treatment an important part of the separation process.</p> Signup and view all the answers

<p>The key advantages of using vertical separators or cyclones (centrifugal separation) are to save weight, space, or improve separation.</p> Signup and view all the answers

<p>There must be a certain minimum pressure difference between each stage to allow satisfactory performance in the pressure and level control loops.</p> Signup and view all the answers

<p>The second stage separator receives production from wells connected to the low pressure manifold, in addition to output from the first stage separator. The pressure is now around 1 MPa (10 atmospheres) and temperature below 100ºC.</p> Signup and view all the answers

<p>The oil heater is used to reheat the oil/water/gas mixture, which makes it easier to separate out water when the initial water cut is high and temperature is low.</p> Signup and view all the answers

<p>The heat exchanger is normally a tube/shell type where oil passes though tubes in a heating medium placed inside an outer shell.</p> Signup and view all the answers

<p>The final separator is a two-phase separator, also called a flash drum, where the pressure is now reduced to atmospheric pressure of around 100 kPa, so that the last heavy gas components can boil out.</p> Signup and view all the answers

<p>To allow controlled separation of volatile components, achieve maximum liquid recovery, stabilize oil and gas, and separate water.</p> Signup and view all the answers

<p>It can cause flash vaporization, leading to instability and safety hazards.</p> Signup and view all the answers

<p>5 minutes.</p> Signup and view all the answers

<p>To reduce the effect of slugs (large gas bubbles or liquid plugs).</p> Signup and view all the answers

<p>Oil level control loop and gas pressure loop.</p> Signup and view all the answers

<p>Low oil level causes gas to exit via the oil output, leading to high pressure downstream.</p> Signup and view all the answers