Optimisation in Upstream Oil

Mervyn Grist (Mervyn.Grist@dti.gsi.gov.uk) from the DTI's Oil & Gas Office in Aberdeen has reviewed the three articles that follow in this section (Achieving Sustainable Production Optimisation by Automating Asset-Level Production Engineering Tasks Usually Performed Manually, Optimising Through Integration: RESOLVE Allows Diverse Engineering Packages to be Solved as a Single System and Stochastic Integrated Asset Management Helps Choose Best Field Development Strategy).  Here he gives his take on the software-aided approach to system optimisation.

It is well known that the human mind is poor at resolving multivariate problems and that mathematical formulation with algebraic or numerical optimisation is a better plan than trusting experienced persons or historic settings.  This is true at all sorts of levels in the offshore industry.  Yet with the now increased number of UKCS operations, the range of sizes and types of producing fields and the scope of the producing infrastructure, the need for optimisation at many or all levels is plain.  Obstructing a rationalised, software aided approach is a requirement to maintain competition, the multiplicity of ownership of facilities and a tradition of joint venturing.  Hope is, however, with us due to the recent but wide adoption of licence portfolio management and the determined establishment of “core” areas by previously widespread operators.  All this is now abetted by the software companies that have seized the opportunity to provide the means to integrate the independent models of each of the hydrocarbon getting operations and then optimise the result.

Their goal is not new and attempts to integrate sub-surface production + well models with flowline networks have already been made.  Also from the chemical industry we have process simulators applicable to offshore installations and network models have been applied to onshore pipeline systems.  However, as the authors of the articles in this section show, an overall integration is now both possible and beneficial because the integration model can have an optimising feature.

As the articles point out, past limited approaches mainly assumed a unidirectional flow of unchallenged data from the upstream unit operation, whereas in fact there is always a range of uncertainty and the possibility of serious shortfalls.  The integration/optimisation software now described offers means of risk assessment, planning and control.   The software is available for different complexity levels from the all embracing to just one plus one activity.  All are, however, steps in the right direction and I hope the industry will seize the baton and run with it.

There are inevitably some caveats.  For example; large old production systems with spare capacity fed by long established fields with stable low oil cut wells will probably not benefit very much although I have been surprised by the effectiveness of process simulators. Finally it must be remembered that the methods described are only part of the solution for the future in a maturing area.   They are not a substitute for selective infill and replacement wells, planned maintenance, and judicious investment to replace failing elderly equipment.