The DAR technology

based on the patented ERV© invention

First Universal Inflow Control System (UICS)


The Density Activated Recovery (DAR) by Innowell is a new generation inflow control technology based on simple and robust mechanical principles, that resolves the challenges associated with current inflow control technologies and provides truly game-changing capabilities:

  • It can control any undesired fluid regardless of fluid properties – even water in low-viscosity oil reservoirs
  • It works independently of reservoir conditions, opening up for increased recovery anywhere, with no negative impact on production
  • It imposes a negligible pressure drop on the reservoir inflow, thereby allowing unconstrained oil production

The DAR technology therefore represents a new generation inflow control technology: the Universal Inflow Control System (UICS).


In many high-productivity fields, oil recovery has been radically improved through downhole inflow control, initially through passive fixed-geometry Inflow Control Devices (ICDs) and later through Autonomous ICDs (AICDs), which discriminate between wanted and unwanted fluids. There are however challenges with existing technologies:

  • ICDs cannot distinguish between wanted and unwanted fluids
  • Both ICDs and AICDs restrict oil production due to large pressure drop
  • AICDs will not work for reservoir fluids with small viscosity contrasts
  • AICDs are sensitive to uncertain variations in reservoir properties
  • There are challenges associated with mud handling during well clean-up

If these gaps and limitations of existing technologies were sorted out, higher deployment rate of downhole inflow control could be achieved, especially for maximum reservoir contact wells, which typically penetrate several formation layers with large variations in reservoir properties.


The goal for the development of the DAR technology was to enable inflow control without limitations by providing solutions to known gaps in existing technologies. This way, inflow control as a very successful IOR technology could become available to a substantially larger number of fields and wells, regardless of fluids and reservoir conditions.

Our approach

Innowell’s DAR technology requires negligible pressure drop and works independently of fluid viscosities, pressure conditions, local inflow rates and reservoir properties. Negative consequences of geological uncertainty are thereby eliminated, and sustained high oil production can be combined with an insurance against loss of revenues caused by early breakthrough of water and/or gas.

Early visualisation of the technology.

Working principle

The DAR technology is based on the ERV© invention, which is a patented technology for controlling fluids with different densities. Density is a reliable physical property to use for identifying different fluids normally present in wells, like oil, gas, water and well construction fluids.

Individual fluid control modules are designed to automatically react to fluids with different densities and control their flow by use of flotation elements that distinguish between desired and undesired fluids. For example, a water control module has a flotation element with a density somewhere between that of oil and water, thereby closing for water and opening for oil. The binary characteristics of the DAR system ensure it is either open or “closed”.

When “closed”, there is always a small “control flow” through the fluid control module to ensure that it can continue to identify and react to the fluids flowing through it, thereby allowing it to re-open if oil comes back. This dual ICD functionality allows for an individual control of the flow rate and restriction in either position. The operator can also specify the limiting volume fractions of undesired fluid, at which the fluid control module shall close and re-open, respectively.

The fluid control modules are integrated in the lower horizontal well completion using an assembly developed for this purpose: the DAR Assembly. This assembly ensures correct orientation and functionality of the control modules.

Achievements and benefits

Prototype testing of the DAR technology performed in a state-of-the-art HPHT test facility for inflow control technology in Norway was a huge success! Testing with real reservoir fluids at reservoir conditions demonstrated excellent results, robustness and repeatability in controlling both water and gas! The most important benefits of the DAR technology are listed here:

  • Automatic control of fluids at sand-face based on density differences rather than viscosity differences
  • Ability to control water on fields with small viscosity contrast between water and oil
  • Autonomous function:
    • No remote control lines or power requirements
    • No need to shut down production to monitor/verify inflow performance or settings
  • Provides unrestricted oil production unless ICD effect is requested by operator
  • ICD functionality in closed position
  • Improved clean-up of long horizontal reservoir sections
  • No restrictions on future well operations:
    • Allows pumping/bullheading for stimulation, scale squeeze etc.
    • Inner diameter maintained, allowing well intervention, logging etc.
  • Universal design, independent of variations in reservoir properties:
    • One design and dimension for all positions in the well
    • Easier to implement in heterogeneous reservoirs, long horizontal sections and multilateral/MRC wells
  • Negative consequences of geological uncertainty are minimized
  • Fewer production and injection wells needed in new field developments
  • Reduced GHG emissions


So far, the technology development has led to the following patents:

  • WO 2014/081306 A1
  • WO 2018/080313 A1
  • WO 2019/1603423 A1
  • WO/2020/046135

Patent applications are pending in several countries.