ENBD is a proprietary technology developed with the objective to keep pressure values at optimum levels inside the well during every drilling stage. It uses an innovative system for drilling fluid recirculation and for the relative pressure control that can dampen typical oscillations due to circulation interruption during pipes’ substitutions or any operation performed in wells.
It is therefore possible to drill fields with high over-pressures or sloped/horizontal wells, in witch continuous fluid recirculation guarantees better cuttings removal.

Flow Assurance in Petroleum Industry is the discipline which guarantees the achievement of the life-time production targets of a lifting and transport system, from the reservoir sand face to the storage tanks, by predicting, preventing and solving the problems originated by the behaviour of the transported substances, i.e. gases, liquids and solids either separated or in multiphase conditions.
Along the route from the reservoir to the receiving facilities, reservoir fluids usually undergo significant changes in pressure and temperature conditions. Beyond affecting the liquid/vapour ratio and compositions, these changes of conditions may induce several physical-chemical effects in the fluids, such as decreasing the solubility of some classes of compounds or creating new phases. Moreover, the presence of several phases in the pipes used for transportation (either in the well or on the surface) is the source of several complex rheological and fluid-dynamic phenomena. All these effects are not predicted and described by the basic thermodynamic and fluids dynamic models and affect, often negatively, the transportation process.
Flow Assurance is the technical discipline addressing such phenomena and their effects on hydrocarbon production.

Typical Flow Assurance problems:

• build-up of wax, asphaltenes, inorganic scale deposits or sand
• sudden formation of hydrates plugs
• occurrence of unacceptable flow regimes, like severe slugging
• lack of reservoir pressure required to move hydrocarbons to the receiving facilities
• increased pressure drop caused by high viscosity emulsions
• erosion phenomena due to high fluid velocity or to sand
• build-up of sand deposits or accumulation of liquids in gas pipelines
• restart difficulties due to high yield stress fluids, in particular at low temperatures
• corrosion phenomena due to the settling of water or to the water-wetting of surfaces in emulsions.

Typical Flow Assurance solutions:

• regular injection of chemical products acting as deposition inhibitors, batch use of solvent to dissolve deposits or regular launch of pigs to displace them outside the pipeline
• injection of hydrate inhibitors (either thermodynamic, kinetic or colloidal)
• appropriate selection of pipeline diameter / route or active flow control (by valves or chemical products)
• downhole or surface pumping technologies, multiphase pumping, gaslift
• usage of emulsion breakers
• pipeline diameter or appropriate material selection
• sand control or regular pigging
• yield stress reduction chemicals (e.g. pour point depressants or demulsifiers)
• optimal thermal insulation or active heating
• application of corrosion inhibitors, pigging or appropriate internal coating

Technologies available in Eni:

• PRIMEFLO® (technology in operations) provides detection of in–line blockages and leakages through in a non-invasive internal inspection of oil and gas pipelines based on fast flow rate transfer. 
• MAST - Multiphase Flow Analysis and Dynamic Simulations of Pattern Transition: (technology for design) is a transient one-dimensional simulator of multiphase flows for flow assurance studies. It is able to reproduce complex multiphase systems in order to predict integral parameters (pressure, temperature, geometrical issues) and proper quantities of the flow (such as slug lengths and frequency) for a correct design strategy.