" Easy oil is over" – after decades of utilising existing oil and gas reserves, these supplies are coming to an end and the development of increasingly more difficult areas is under way. With conventional methods, average exploitation efficiencies of 30 to 40% are achieved. An efficient method for increasing the efficiency of oil and natural gas from its wells consists of installing multiphase downhole screw assemblies (MDA) in the wells in the immediate vicinity of the pay zone, and therefore contributing to securing the fossil energy supply for mankind over a longer period of time.
The multiphase pump downhole assembly (MDA) utilises the obvious advantages of displacement pumps in its contact-free design and therefore allows independent control of the two main conveying parameters, delivery pressure and delivery rate. Multiphase downhole screw assemblies were developed for two main uses:
Conveying gas-containing oil sources – this allows use of the MDA in the immediate vicinity of the oil-bearing formation.
Pumping from liquid-filled gas wells.
With its ability to pump oil and gas in almost any fraction, these machines extend the range of conventional downhole pumps and make a significant contribution to producing from difficult wells.
A further contribution is made through the splitting of complete transfer applications into subtasks, which are tackled by corresponding "conveying specialists". For this, MDA's are used downhole in combination with surface-bound multiphase screw pumps and with it levels of efficiency previously not achieved are obtained.
Screw pumps have been very well-known in the oil and natural gas industry for many years. They are used especially for higher viscosity media or to significantly modify the transport volume by regulating the speed. Owing to their volumetric character, they are also ideally suited for the transport of multiphase mixtures (oil, water, and gas).