The DAR Technology

DAR - Density Activated Recovery. A technology based on the ERV© invention.

The challenge

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 related to 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

The goal for the development of the DAR technology is to enable inflow control without limitations by providing solutions to known gaps in existing technologies. This way, successful IOR technology becomes available to all horizontal wells, regardless of fluids and reservoir properties.

Our approach

Capabilities that differentiate the DAR technology

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.

System description

The Density Activated Recovery (DAR) technology by Innowell is a modular Inflow Control System (ICS) based on simple and robust mechanical principles that resolves all the challenges listed above and therefore represents a new generation of inflow control technology: the Universal Inflow Control System (UICS).

Furthermore, the DAR technology imposes negligible pressure loss unless an additional ICD effect is requested to delay water/gas breakthrough. Hence, unconstrained oil production and local control of ANY undesired fluid can now be achieved, which opens up for increased recovery anywhere, with no negative impact on production.

Prototype testing of the DAR technology has been a huge success! The tests were performed in a state-of-the-art HPHT test facility for inflow control technology in Norway. Testing with real reservoir fluids at reservoir conditions demonstrated excellent results, robustness and repeatability for both water and gas!

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 drilling/completion fluids, oil, gas and water.

The DAR ICS consists of fluid control modules, which are designed to automatically identify the flowing fluids and control their flow rate 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.

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. The operator can specify the limiting volume fractions of unwanted fluid, at which the fluid control module shall close and re-open, respectively.

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

Achievements and benefits

  • Automatic control of fluids at sand-face based on density differences rather than viscosity differences
  • Ability to choke back 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
  • Does not choke 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 ICS 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