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Reservoir Optimization

The open hole FLEX-WELL® design provides options for efficient long-term reservoir management and risk


Oil and gas reservoirs with a high degree of rock heterogeneity created through complex depositional environments, diagenetic or structural overprint, demand well completion solutions enabling response to changing reservoir conditions over the life of well to maintain maximum well delivery.

The open hole Flex-Well® design provides maximized reservoir contact with cement-less full bore liner, efficient zone isolation by WAB's or WLP's and the number of zones being dictated by the geology of the reservoir and not by hardware capability (e.g. control lines, inner string, extended reach etc.) 

The WFVTM with Multi Position provides the operator with the option of varying the differential pressure across the rock interface of each zone to balance out the difference in reservoir permeability. The Flex-Well will not only balance out heel toe effects but also control expected (or unexpected) permeability variance, along with water or gas breakthrough. 


In specific projects modelling is used in the configuration of the Flex-Well to quantify and ensure the reservoir management benefits.

To partner up on modelling capacity Welltec has engaged with the consultancy company Lloyd's Register (LR) earlier Senergy LEA. LR provides Welltec with independent simulations using best in class industry modelling software and bring global experience from similar well challenges.

This enables Welltec® to support a solution-based approach with optimized well performance for the customer in mind.

Well performance benefits can be quantified through well flow modelling capturing the 3D design of the well completion and interaction with the reservoir. With this simulation we can estimate:

  • Well capacity
  • Pressure loss through well
  • Risk of flow behind packers
  • Optimum flow valve configuration
  • Stimulation efficiency
  • Erosion risk
  • Correlation between flow valve choke position / annular pressures / zonal flow rates.


Below is an example of a horizontal multi-zone Flex-Well completion designed for water management across matrix and oil producing fault zones with large permeability contrast. Eight annular sealing packers are ensuring long-term zonal isolation between the varying permeability zones with seven Welltec Flow Valves (WFV with Multi Position) are providing the operator with risk mitigation options.

This solution enables initial maximum production to be targeted from the main fractures, once the water is out they can be choked back or shut off, with the secondary fracture system produced. Finally, as production dictates, the matrix can be stimulated and produced.


Below is an illustration of a 12 zone horizontal well within a reservoir of varying degrees of rock permeability.

With a Flex-Well configuration, each of the 12 zones can be equipped with a WFVTM with Multi Position enabling the operator to choke back the high water cut zones. These zones still producing at reduced rate maintain some oil production, with the impact resulting in a higher drawdown on the lower water cut zones.

Over the life of well the Flex-Well completion provides risk mitigation with respect to geological uncertainty delivering oil gain.

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Segmented Flex-Well® design increase options to mitigate reservoir uncertainty and maximize the economic value of wells. 

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Welltec® Flow Valves (WFVTM) enabling changing reservoir conditions over the life of well to maintain maximum well delivery.