Development of Moomba North Gas Field: Lessons Learned From Integrated Study Followed by an Infill Drilling Campaign

摘要

Field development planning based on integrated studies, including construction of a 3D geo-model, is an accepted standard for development of larger assets. The need to keep field development plans 'evergreen' is well recognized, but often difficult to realize in practice. This paper will focus on the results of a drilling campaign that followed an integrated study previously described in SPE paper 62901(Herweijer et al., 2000). As with many drilling campaigns, the results covered a range from very positive to negative outcomes. This paper will show how the result of the campaign, which was an overall success, was affected by: - The modeling process, which assumed a base case with perturbations. It became anchored on a specific, optimistic, fluid contact scenario, rather than including a realistically wide range. - The process of multi-disciplinary work, which, although rigorous, did not in itself guarantee that a realistic range of scenarios had been covered. - Changes in team membership prior to execution of the infill campaign. This lead to a partial lack of ownership, resulting in the missing of signposts that could have lead to re-tuning the campaign by accounting for more downside scenarios. - The relatively elaborate study and modeling process, which discouraged updating and hence lead to poor integration of some early negative drilling results into the model. The conclusion of the paper is that the whole study became somewhat 'model-centric'. The model served as an unbeatable 'truth': trusted more than pre-model mapping, not fully connected to post-model 'mass production' infill drilling results, and used on problems to which it was not suited. As a result of the lessons learned we have been able to assess the real value of knowledge continuity and model 'ever- greening' from early stages of development through to later ‘harvest' drilling.