Energy Efficiency and Secondary Recovery: Two Management Options for a Mature Fields in Ecuador
Authors: Ayala Diego Roberto , Padilla Wilson Leonardo , Ayala Silvia Alexandra 
Published: March 2023

AbstractThe strategies focused on solving the issues of a mature field should consider the declining production in order to stablish future investments, to not fall into costs that could reduce competitiveness and in the worst case reduce profit.The Block 49 (B49) is an oil field with almost 50 year of exploitation with typical mature field related problems as low productivity, reservoir depletion, high rate of water production which requires of a group of mechanism to become a competitive field in the current market conditions. The optimization of the recovery factor and the implementation of an energy efficiency model were the axes to reduce the OPEX and reach a barrel with a production cost of 5.20 USD.The main goal of waterflooding in B49 field is maximizing oil recovery while minimizing water production, in this case, the injected water for the secondary recovery is the formation water from the north and south zones of B49. As consequence, the recovery factor increased from 21% to 26%.For many years in Ecuador, the gas as consider as a waste sub product, for this reason the gas flaring was an accepted practice, however, since 2009 Ecuador’s national oil company, has been executing an ambitious Energy Efficiency Program. This Program, also known as Optimization of Electricity Generation and Energy Efficiency (OGE&EE), is a comprehensive development on generation, distribution and transmission of electricity, as well as the development of facilities for the capture and transportation of Associated Gas (AG). The Program consists of a cluster of projects in an area covering 25,000 sq. km., 17 oil blocks, 56 oil fields and more than 66 facilities. The results of this Program can be summarized as following:Multiple power plants with a combined power of 325 MW, 95 MW of these power plants can use associated gas as fuel. More than 200 km of power transmission and distribution facilities to deliver power based on economic and environmental merits; and, Approximately 17 km of gas gathering and transportation facilities of a total scope of 100 km, bringing deteriorated facilities up to standard and implementing waste heat recovery systems. The OGE&EE Program also had interconnected the oil industry electric grid to the national grid, which helps to optimize national renewable energy (hydropower).In 2015 Ecuador’s national oil company joined the World Bank’s initiative "Zero Routine Flaring by 2030", the Government of Ecuador also joined this initiative on 2018, and as part of Ecuador’s national oil company energy efficiency program, since 2015 it has been working to develop project and financial solutions to increase more Associated Gas Power Generation and to gather Associated Gas from lower scale flares.This approach uses gas production at the well before any flaring, the B49 field uses the production of 12 wells for electricity generation, the average daily demand is 3MW (72MWH each day). The electric generation of B49 meet the targets of efficiency since it uses gas of low-calorific value in high efficiency generator sets, 100% of the energy need of the field is generated, 16MMcf of sweet gas is used monthly, stops the emission of 533 Ton CO2 eq/KWH, and results in 562 M USD of savings due to not diesel consumption. Problems as CO2 emission reduction, gas availability, gas flaring limitations, facilities to maintain the pressure, gas transportation (processing-distribution), depletion of the reservoir, water injection, and increasing of the BSW are issues addressed in this research.