Chemical Stimulation Pilot at a Heavy-Oil Field: Key Considerations, Workflow, and Results

Abstract

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.

A study of the suitability of autoencoders for preprocessing data in breast cancer experimentation

“…We repeated the complete procedure ten times for each compared preprocessing technique to avoid bias due to initial random selection and took the mean of the pvalues. The source code and the data (including the training and test partitions) used in this part of our analysis can be found published on the web [53]. According to the p-values obtained for ER, PR, Ki67 and HER2 regarding MORT and REC in Cox regression, we could state that a transformation based on the use of an automatic binarization after autoencoding would be better qualitatively than the other options, but not quantitatively.…”

Determinación y análisis estadístico de la composición de los gases producidos en un piloto de recobro mejorado

“…En este sentido, se han implementado diferentes proyectos de desarrollo tecnológico dentro de los cuales se destacan el Piloto de Inyección de Agua Mejorada y el Piloto de Inyección de Aire para Recobro (PIAR), ambos ubicados en la cuenca de los llanos orientales, una de las zonas más productivas del país [2]. El PIAR se desarrolla en el campo Chichimene (Meta, Colombia); este campo se caracteriza por producir crudo extrapesado, el cual representa el 11.5 % de la producción total de crudo diaria en Colombia [5]. El factor de recobro para este crudo, con viscosidad superior a 2000 cP y gravedad API entre 7° y 10°, puede estar cerca del 10 % [6]; por medio de la inyección de aire, se espera que este porcentaje incremente alrededor de 50 % considerando los resultados obtenidos en proyectos exitosos de este tipo [7,8].…”