Applied Framework for Managing Sustainable Retrograde Gas Condensate Reservoirs

Abstract

Managing retrograde gas condensate reservoirs comes with its set of challenges. To maximize recovery and ensure the sustainability of reservoirs, the reservoir engineer must ensure the proper well placement, choose the best completion, and perform regular reservoir surveillance. This paper discusses an applied framework for managing retrograde gas condensate reservoirs, to ensure the longevity of the reservoir and maximize performance. The process of managing sustainable retrograde gas condensate reservoirs entails proper well placement, which can be achieved through an in-depth assessment of the targeted geological formation in terms of reservoir development. This is further assessed through acoustic impedance maps, seismic data, and any reservoir modeling available. Also, choosing the correct completion of the well is a function of the information obtained from well logging and sampling. Finally, proper reservoir surveillance should be implemented after the well is put on production. Information such as pressure and temperature data, zonal production contributions, and pressure build-up tests should be obtained regularly. Following proper well placement, correct completion choice, and regular reservoir surveillance can aid in maximizing production and ensure the sustainability and longevity of the reservoir. Utilizing a comprehensive geological model to study both the structure and development of the reservoir can aid in choosing the optimum well type: vertical, horizontal, or deviated, as well as the required completion. Once well logging and sampling are performed, an optimal completion method can be deployed. Typically, porous sandstone reservoirs require some sort of sanding control method to not impede the production of gas. Tight gas reservoirs would require fracking to increase permeability, and sand control to reduce sand production. As an alternative, tightness can also be overcome by drilling horizontal wells with high inclination to increase reservoir contact. Finally, reservoir surveillance is of utmost importance for retrograde gas condensate reservoirs. Reservoir fluid characterization aids in determining the dew point pressure, after which condensate starts to produce. Several methods are discussed to reduce the effect of condensate production. This paper discusses a framework for managing a retrograde gas condensate reservoir, where successful planning, completion, and surveillance can be applied. The article also sets forth a flow chart to exemplify the optimum path to manage and sustain retrograde gas condensate reservoirs successfully.