Optimizing Production Performance, Energy Efficiency and Carbon Intensity with Preformed Foams in Cyclic Steam Stimulation in a Mature Heavy Oil Field: Pilot Results and Development Plans
Authors: Pérez Romel Antonio , Rodréguez Héctor Arnoldo , Rendón Gabriel Julian , Plata Brayan Guillermo , Salinas Lina Marcela , Barbosa Carolina , García Luis Eduardo , Rojas Fernando Andrés , Orrego Jorge Armando , León Lucy Johanna , St. Bernard José Gabriel , Manrique Eduardo Jose 
Published: April 2022

Steam injection has been the thermal Enhanced Oil Recovery (EOR) to develop heavy and extra heavy crude oil reservoirs worldwide. However, oil price volatility, trends in the energy transition, and steam injection carbon footprint are influential factors limiting the commercial deployment of steam-based EOR technologies. In response to these new challenges, hybrid steam methods such as cyclic steam stimulation (CSS) with preformed foam have become energy and environmentally efficient technology revitalizing mature wells in Colombia.

Since mid-2019, six field tests of preformed foam injection previous to the steam cycle have been implemented to optimize CSS processes in mature wells (&gt; 10 cycles) of a heavy oil field located in the Middle Magdalena Valley (MMV). The technology includes injecting the foaming agent with nitrogen as non-condensable gas using a specially designed wellhead mixer that can generate a stable foam at the surface and inject it as a diverting agent before the steam cycle is injected.

This paper describes the field test evaluation from design to production performance, including foam formation monitoring strategies based on produced water geochemistry. Results will also be described in terms of energy efficiency (E.E.) and carbon intensity (C.I) indexes, defined as criteria to evaluate potential development plans in different assets of the MMV.

The first two pilot wells initiated last July 2019 have reported incremental oil recoveries that exceed 20 KBO. As of October 2021, one of the wells is still producing above the baseline, representing an improvement in E.E. and C.I. Once the baseline production is reached, a second CSS with foam is scheduled as part of the EOR program. In December 2020, two additional tests were implemented. Higher steam injection pressures were observed, suggesting the flow diversion to lower permeabilities and unswept oil intervals as recorded during the first pilot wells. Both wells are showing encouraging performance, and results will also be described. Regarding the geochemical analysis, the increase in the total concentration of water-soluble organic compounds (WSOC) confirms the production of unswept zones within the pay interval. Specific WSOC were identified (i.e., Ox and OxS classes, where X ≥ 2, detected by (-)ESI FT-ICR-MS) as natural tracers to complement ongoing project interpretation. Based on the results observed, different development scenarios are under consideration.

This study provides new insights to optimize CSS in mature wells operating since the early 1980s supported by a novel surface foam generator, affordable monitoring strategies, and developed energy efficiency indexes aligned with lower carbon footprint goals established in Colombia in the era of the energy transition.