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This paper presents the planning and execution process for a key matrix stimulation pilot project performed in the heavy-oil Chichimene field in the central Colombian province of Meta. An understanding of multiple aspects of formation damage, candidate well selection, laboratory testing, treatment fluid selection, onsite quality assurance/quality control (QA/QC), diversion considerations, and placement techniques was fundamental to achieving a successful treatment design. Results are presented in terms of a percentage increase in production rates, percentage decrease in decline rates, and skin value reduction. Because of current oil and gas industry economics, it is crucial to evaluate the return on investment for any well intervention campaign and apply an assurance process to help quantify the desired improvement in production results. This approach is primarily based on a workflow that includes several key steps: understanding the nature of and characterizing formation damage, reviewing necessary laboratory testing, validating candidate well selection, determining economically viable placement and diversion techniques, and performing QA/QC on site and post-treatment. Production results from the first five pilot wells are presented along with a review of the production decline and continuous improvement actions. Understanding the induced damage that can be caused by drilling operations, heavy-oil properties, and the potential for emulsion and wettability alteration, in addition to the need to ensure total fluid-fluid compatibility combined with low interfacial tensions (IFTs), can be crucial to achieving results above initial estimates. Aligned with current critical well intervention economics, a rigless operation with coiled tubing (CT) through the Y-tool of an electrical submersible pump (ESP) was selected instead of a traditional intervention with a workover (WO) rig. Because of long treatment intervals and large permeability variations, stages of foamed brine were included in the treatment schedule as a diversion method. A tuned frequency and amplitude tool was used to enhance the placement and effectiveness of the treatment as part of a CT bottomhole assembly (BHA). QA/QC sampling was valuable for treatment monitoring and enhancement. This paper presents a valuable basis for future candidate well selection and stimulation treatment design. The workflow and its application are a good reference for analogue fields in Colombia and other areas.

Chichimene is the third most important field of Colombia, with an original oil in place of USD 3.1 million barrels, producing an extra heavy oil of around 8 API, characterized by high viscosity and reduced mobility. The estimated recovery factor was around 3%, and the reservoir pressure was declining drastically; because of this, it was necessary to urgently implement an enhanced oil recovery project, since without immediate intervention, the reservoir and field production would be seriously affected. A thorough screening process was performed among diverse EOR options, and waterflooding was selected as the best alternative for maintaining reservoir pressure and increasing the recovery factor. The main challenge was to have a rapid implementation for the entire reservoir, considering that this region has reported community issues derived mainly from water management disagreements and inconformity with stringent labor requirements. Additionally, lengthy environmental permits and high deployment expenditures were factors that affected field development plans. The research of an effective technology for the field-specific conditions and a low deployment cost indicated dumpflood as the best alternative, since it enabled injection from a deeper water formation to an upper production target zone through a smart BHA, substantially reducing injection facilities investment and operational costs. Time savings were identified, eliminating additional requirements for environmental permits. The main concern was that this technology has never been implemented for extra heavy oils. Simulations in a steady state simulator validated the feasibility of the dumpflood technique in the field. Models of the production and injection zones evidenced the pressure needs and the necessary BHA adjustments to meet the target rates and to define the completion model with the specific equipment to perform the operation. Implementation started in the South West area of the field and was deployed with three waterflooding patterns in a record time of three months. After nine months of operation, the reservoir pressure augmented in the surrounding wells, and the failure indicator of the electrical submersible pumps was reduced by a factor of 20%. As a major milestone, the average field production climbed by approximately 10,000 bbl/d. Considering the successful results, the project was extended to 20 waterflooding patterns in other areas of the field, the waterflooding project was approved and sanctioned one year after the pilot startup and therefore over 20,000 barrels of oil equivalent were incorporated to the proved reserve balance.

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Maximize oil production at the lowest cost, reduce the process facilities used for secondary recovery water injection projects and increase the static pressure of mature reservoirs was a need in Chichimene Field due to the challenging oil market conditions and the declining oil production rates. The legacy solution used by Ecopetrol consisted in producing water with artificial lift and then re-injecting it through horizontal pumping systems. This water injection method did not maximize oil recovery with the available resources. Ecopetrol and Baker Hughes implemented the Dumpflood completion with electrical submersible pumping to address the challenges encountered in Chichimene field. The Dumpflood completion is a closed loop concept where water is produced and injected in a single well avoiding surface processes. This implementation allowed Ecopetrol to develop secondary oil recovery in a simplified and cost effective completion. This paper will present the results of the first pilot of Dumpflood completion in Chichimene Field in Colombia. This Promoted enhanced oil recovery in the target injection zones, in addition, significant savings in capital expenditures were obtained due to the reduction of surface production tubing and required licenses for the oil industry in Colombia. Operating expenditures such as maintenance, water treatment, and energy costs were also reduced. The success of the Dumpflood completion with electrical submersible pumping permitted the initiation of a change in the legacy water injection method in Chichimene field. It was demonstrated that the oil market is continuously in need of innovative completions solutions to optimize resources and oil recovery.