By Sandro Maciel (Principal Partner Well Intervention)
Petrobras' divestment plan is closely monitored by the entire national and international O&G market, as well as by society. Most of the assets sold or offered for sale would have little chance of growing in the hands of the state-owned company, not because of the company's technical incapacity, but because of a strategic decision to focus its investments on more profitable assets in the offshore area, especially in deep waters (pre- salt), which due to its inherent complexity consumes billions of dollars in resources.
Over time, with production, the depletion of oil and gas reservoirs takes place, leading to a reduction in production in the fields, requiring new drilling campaigns for producing wells and/or the use of secondary and tertiary recovery techniques. These actions cause an increase in production costs, which can lead to a point of economic unfeasibility. This is one of the determining factors in the decision-making for the closure of activities and the consequent decommissioning of the facilities. Many mature and marginal Petrobras fields are close to this condition today, however, they may still be attractive when operated by companies, leaner and more flexible, specifically focused on this type of operation.
Thus, the sale of onshore fields and some mature offshore fields prevents the early decommissioning of production structures, extending the useful life of these assets, extending the useful life of the fields, additionally generating employment, income and economic activity . The extension of the useful life of the fields, presents itself as a solution with great “cost-benefit”, in addition to being socially positive, as it guarantees a higher level of economic activity in a sector that pays above the country's average.
It is a fact that around 70% of the world's Oil & Gas production comes from mature fields (Brownfields), which are fields that have been producing for over 25 years. It is noteworthy that Brazil is currently at a point outside this curve, as with the advent of offshore production in the pre-salt, most of our production comes from relatively young fields (Greenfields) with less production time.
Much is said about the recovery factor (RF) of an oil and gas producing field, which is nothing more than the ratio of the volume produced over the total estimated volume of the reserve (whether it is 1P - Proved; 2P - Probable or 3P – Possible). According to estimates, the world RF for oil is around 35%, to have a dimension of the importance of increased recovery in mature fields, consider that a 1% increase in the world recovery factor is equivalent to 2 years of current world demand of oil and gas.
Fig.#1: Efeitos de 1% adicional no FR – ANP 2017
It is estimated that in Brazil, the estimated average RF of land reserves is around 31%, according to 2017 ANP estimates, an increase of only 1% on the Recovery Factor (FR) would mean an additional production of around 250 MMBoe (million barrels of oil equivalent) (Fig. 1). These data demonstrate the great potential for the revitalization of mature fields, as long as it is justified on a case-by-case basis, both technically and economically.
Fig. #2: RF of Brazilian reservoirs by environment – ANP 2017 Fonte: ANP/SDP/Sigep
With this challenge in place, it is necessary for the Brazilian O&G industry to respond quickly with solutions for each scenario, whether technical and/or economic, faced by operators.