Esso Australia Resources Pty Ltd, along with joint venture partner BHP Billiton (Bass Strait) Pty Ltd, recently undertook drilling of development wells in order to access new reservoirs in the Gippsland Basin, offshore Victoria. This development of new reservoirs required confirmation of the drive mechanisms in the different stacked reservoirs to finalise the completions for each of the wells.
To confirm the pre-drill understanding of the reservoir behavior in this particular field the logging-while-drilling formation pressure testing technology was deployed, in a total of five (5) wells, throughout the development drilling campaign. The main objectives were to confirm fluid type and connectivity across the penetrated reservoirs, comparison of the logging-while drilling (LWD) data with existing wireline datasets to confirm drive mechanism and to aid in determining fluid contacts within the penetrated reservoirs.
This paper discusses the advantages and benefits of deploying a formation tester in a LWD environment, the results that were achieved and how these objectives were met. Formation pressure while drilling technology provides many advantages for formation evaluation capabilities. In particular operators can collect formation pressure measurements in highly deviated wells whilst reducing operational risks and minimizing costs. The measurements are acquired with the same technology that is used in equivalent wireline formation testers and therefore provide the same high quality data but in a drilling environment. In addition the LWD formation tester has proprietary features to optimize achieving valid pressure measurements during each deployment which will be discussed further in this paper.
As a result of the five successful separate runs a better understanding of the drive mechanisms of the separate reservoirs was achieved which enabled adjustment and optimization of the completion design. In addition, the formation pressure data was used to determine fluid contacts within reservoirs and aid in resolving LWD petrophysical log ambiguity.