TUBINGLESS COMPLETIONS IN THE SURAT BASIN

Abstract

Oilfield operators have always looked for ways of reducing the costs of oil and gas development projects and especially when investment costs were critical to project economics. Tubingless completions have evolved over the last 30 years in North America to fill the need for reduced investment costs particularly in the case of fields with either limited reserves or limited profitability.

Tubingless completions basically utilise small diameter tubulars to function as both production casing and flowstring. The tubulars are cemented in the borehole, not to be removed or recovered until the field is depleted and/or the well abandoned. The technique is limited in application to those fields with no corrosion or wax or hydrate problems and with a limited requirement for reservoir stimulation and workovers. The greater the number of operations performed within the tubingless well bore the greater the risk of losing the well.

The main benefits of tubingless completions are as follows:

Reduction in development well completion costs.

Marginally productive hydrocarbon zones can be completed and tested.

Completion of individual gas zones of multi-pay wells within their own permanently segregated flowstrings at much lower capital and operating costs.

The experience this far with Kincora gas field development wells indicates the tubingless completion method to be completely feasible for gas wells drilled in the Surat Basin and possibly in other areas of Australia.