Supported by an efficient and intuitive UI & Analysis tool to gain an understanding of the subsurface material and stress state.

Elfen Horizon can provide operational limits to mitigate potential risks from well instability, fault slip, reservoir compaction and mudline subsidence.

The field scale reservoir and overburden are 3D structures with complex material and stress states that cannot be accurately described by traditional 1D methods.

Elfen horizon ensures that the geomechanical aspects of the reservoir receive as much attention as the fluid flow

  • Static and dynamic reservoir field scale modelling
  • Fully coupled to reservoir simulators
  • Reservoir compaction, subsidence, fault reactivation
  • Complex salt structures, stress and material state
  • Cap rock integrity
  • Induced seismicity

Modelling Capabilities

  • Large scale – multi field models – up to 20 million elements with the ability to sub-model to wellbore scale
  • Fault systems represented discretely
  • Non-linear elastic and plastic properties
  • Integration of input and output with 3rd party software packages
  • Detailed well trajectory assessments
  • One-way or fully coupled to reservoir simulators


Dynamic sand production assessment accounting for reservoir stress changes due to depletion, fault slip and stress arching

Detailed overburden stratigraphy including faults and well trajectories

Examples of depletion and injection induced subsidence/uplift through overburden to seabed

Fault slip due to depletion – orientation and magnitude of slip

Detailed overburden stratigraphy including faults and well trajectories

Cross sections through sediment surrounding a salt structure

Fault network above salt structures – off-shore Brazil

Coupling of pore pressure from reservoir simulator

Elfen horizon helps provide operation limits to mitigate potential risks which can lead to reduced cost, improved safety and increased productivity.

Features and Benefits

  • Log and seismic data can be imported directly to initialise the material and stress conditions
  • Assessment of the subsurface material and stress state at both preproduction and throughout production
  • Enhanced understanding of the geomechanical environment identifying regions of stress arching and assessment of caprock integrity
  • Capture subsidence and compaction to assess its impact upon subsea infrastructure over the duration of the field
  • Provide limits on depletion and/or injection levels
  • Well trajectory assessment and planning of potential infill drilling
  • Identify fault slip and fault reactivation and assess its impact upon the performance of the well string
  • Undertake sensitivity studies to minimise the risk over the lifespan of the field
  • Ability to link to industry standard reservoir simulators

Elfen Horizon Reservoir Modelling can me utilised in multiple industries

Offshore case study

Modelling of the BS-4 Atlanta Field to Assess Fault Reactivation and the In-Situ Stresses during Production

The Project

QGEP is the operator of the BS-4 block and expect to start production in late 2014/early 2015. Prospect NE lies in the north central section of the BS-4 block and consists of a 4 way dipping structure associated with geological salt deformation in the basin. The prospective sequence consists of Eocene to Albian deepwater turbidite sandstones, Figure 2; the primary objectives are the Eocene and Upper Albian turbidite deposits. 

The Software

The pre-defined faults within the BS-4 domain are modeled with double-sided discrete contact which permits sliding of the faults to occur. A Coulomb friction law is assumed for the faults; the Coulomb friction law within Rockfield’s in-house software Elfen is written in terms of the normal and tangential effective stresses on the faults. A cohesion and coefficient of friction of 0 MPa and 0.2 respectively were used for the Coulomb friction law applied to the faults; fault properties were selected at the lower end of a realistic range.

Read white paper

Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now