Having the means to efficiently evaluate different forms of artificial lift early in the planning cycle significantly improves the ability to influence other planning decisions (well count, well design, facility capacities etc.) and to realise the potential upsides made available by new artificial lift technologies. Artificial lift screening involves evaluating multiple criteria including rate, well design, cost, reliability, environmental impact, flow assurance, solids handling, operability etc. This paper focusses on a fit-for-purpose methodology to evaluate well production performance for a wide range of artificial lift techniques including Electric Submersible Pumps, Gas Lift, Sucker Rod Pumps, Progressing Cavity Pumps, Jet Pumps, Hydraulic Submersible Pumps and Hydraulic Piston Pumps. The five important attributes of the methodology presented are:
Consistency: To ensure a fair comparison is made when evaluating each lift technique, the same assumptions about reservoir performance, fluid properties, multi-phase flow behaviour, geomechanics etc. are used.
Auditability: Later in the development planning process, decisions and assumptions will inevitably change, and it is important that there is a proper audit trail regarding how artificial lift screening had been performed to help understand the potential impact of these changes.
Efficiency: Early in the field planning cycle, many alternative well counts, well designs and facility configurations will be under evaluation, and assumptions about reservoir and fluid properties will be changing as new data become available. It is therefore important that the artificial lift screening method can be readily applied to accommodate the many scenarios.
Technical Rigour: While detailed artificial lift design is not required (or desired) at the screening stage, it is important that the screening methodology applies a fit-for-purpose level of technical rigour to ensure reliable results are achieved and opportunities are not missed through the misapplication of various industry ‘rules of thumb’.
Vendor Independence: While sufficient industry research is required to understand the available technologies and new innovations, the screening process should be independent of any particular equipment vendor to prevent any undue bias.
The well performance calculations use a nodal analysis approach to develop inflow and outflow curves at the depth of the artificial lift equipment. Then, using knowledge of the fundamental operating principals of the artificial lift techniques, calculations are performed to determine the range of production rates achievable based on constraints including power, flow capacity and gas handling ability.
The paper will also present a range of real field cases where these screening calculations have been applied to deep water subsea, onshore conventional and coalbed methane (CBM) developments.