rhiDEMS is a web-based tool for decommissioning estimating, strategy evaluation and scenario planning. It's unique combination of benchmarked data, composite metrics and operator experience ensures effective support of your decision-making process, and evaluation of both ‘what ifs’ and risk assessments. This bespoke tool can demonstrate the impacts of where, when, how long, duty holder transfer, and the benefit of introducing NUI mode on overall cost phasing.

Making choices throughout the decommissioning process can be difficult to steer, however rhi has data available to provide clients with a clearer view of the project’s future.

rhi work closely with clients, using our expertise to build a model from their data. rhiDEMS allows clients to build scenarios and test the potential outcomes of a decommissioning scope. What would normally take a team to process in a number of days, can now be done at the press of a button.

The rhiDEMS model, covers onshore, offshore, subsea, wells P&A scopes and is continuously updated with latest project actuals costs.  The toolset enables our experienced consultants to prepare decommissioning estimates quickly and to test a variety of scenarios / strategies interactively and jointly with client teams.

Asset Retirement Obligation (ARO) estimates can be prepared at project conception and updated routinely to reflect changes in facilities layouts, legislation and market conditions throughout the life cycle ensuring the appropriate provisions are set aside and that OGA requirements are complied with.

Offshore Facilities Model Overview

Initial decommissioning estimate models (reference case) are built by rhi experienced personnel jointly with key Project Team members for each of the facilities components using the standard input templates.

rhi metrics and up-to-date rates are applied to the inputs to generate individual facilities estimate models which are uploaded to the Web-App. The model outputs can be viewed on-line.


Input table: rhi developed cost estimate input templates ensure that the full scope is considered and nothing gets overlooked when building the estimate.

Metrics table: These have been developed from actual project close out reports. The Metrics are recalibrated annually to ensure that the impact of new technologies, industry efficiencies and improved data collection are incorporated.

Rates table: ‘current rates’ tables are available within the tool to cater for region specific variances.

Detailed estimate: class 2, 3, 4 estimates can be prepared dependent on the level of available input detail.

Cost summary: is compliant with the industry work break down structure but can be modified for region specific variants.

Web app: link to the rhiDEMS app

What benefits can rhiDEMs bring to your project?
  • Ability to readily develop a detailed bottom’s up cost estimates using tried and tested input templates covering the full scope​
  • Quickly build comparison cost models for a range of differing decommissioning methodologies​
  • Capability to run scenario modelling, test alternative strategies and review impacts on cash flows
  • Ability to incorporate changes to facility inventories and market rates quickly through rhiDEMS interlinks
  • Provides a full audit trail of the estimate basis and the assumptions incorporated


For more information on how rhiDEMS has been used in client projects, click on the links below

Decommissioning Project, Gippsland Basin

sunset offshore Decommissioning Project, North Sea

offshore og Decommissioning Cost Estimate, Canada


Re-Development Project, Persian Gulf

Persian gulf Decommissioning Liabilities, Vietnam