Planning & Following up Well Completion & Workover Activities using Ontology of Operations.

Dr Kazuo Miura, Marcela Coelho, Petrobras

Dr Carlos Damski, Genesis Petroleum Technologies

Luiz Felipe Coutinho Martins, Magda D C Albuquerque, Maria Alice

Prudente, Mariana D Nascimento and Jéssica L Cordeiro, Genesis do Brasil

Abstract

A Petrobras Offshore Business Unit has been applying the well-known Deming’s PDCA Cycle (Plan, Do, Check and Act) aiming to reach a continuous optimization in well completion and workover activities (called as intervention in this paper).A methodology based on Ontology of Operations has been implemented to aid this process of continuous improvement.

The methodology defines the intervention planning as a sequence of standardized operations. These standardized operations are the key point of the methodology. We identified more than 180 operations and defined them based on ontology of operations (Miura, 2004). The activity durations are found in a historical database with more than 600 interventions, spliced in conformity with standardized operations. When splicing the interventions in operations, we can obtain larger similarity among the executed tasks than entire interventions, and that allows its statistical treatment.

This same statistical database is useful, for instance, following up performance of an intervention through the simulations which gives us the statistical variation of operational times. For instance, the Monte Carlo's simulations applied in the operational sequence allow the risk analysis of operational times. Historical data can be queried by year, rig type, oil field, and so on, and in this way, we can get the best statistical distribution curve that fit with the operations times. The analysis that we conducted over these data suggest us that lognormal distribution are the best pattern for these time related operation data.

The virtual intervention simulation technique can be interpreted as a normalization process for operational sequences and it can be used, for example, to benchmark performance of all players involved in workover activities, from the asset team to the service companies.

The methodology allows, in addition, the accomplishment of the intervention post-analysis. The post-analysis makes possible the discovery of operations executed with extreme long or short times, showing both the best durations that should be pursued and the worst durations that should be avoided in future interventions. The abnormal operations are studied in full detail and the lessons learned are incorporate, updating them
 in the templates used in the planning of future interventions. With these initiatives, the methodology can assure continuous quality improvement through a positive feed-back.

This paper discusses the implemented methodology and proposes as a new step, the concept expanded to all well operations, including the drilling activities.