Secondary and tertiary oil recovery technologies are not a common practice in Colombia. There are only 23 secondary oil recovery applications in a commercial level, and tertiary projects are limited to pilots that for different reasons have not been taken to the next level and to steam injections projects (huff & puff) in some heavy oil fields. However, Colombian interest and knowledge about the topic is every time higher and there exist different registers about an important number of initiatives to laboratory level that included modeling tasks for specific fields. This paper looks around the different EOR§ initiatives that have existed in Colombia, from laboratory to field scale; in the same way, the research activities that have been done in the Instituto Colombiano del Petróleo (I.C.P.) of ECOPETROL S.A. are highlighted, where an important percentage of the jobs have been done, and where the necessary tools for modeling and evaluating almost every process exist. There are also presented in this paper the actual efforts in EOR, identifying the technologies for which exist the highest attention and the number of projects in design stage. From the material presented in this article it is possible to understand the EOR potential in Colombia, to identify the increasing interest in the subject, to recognize opportunities in the subject and to learn from the applications done until now.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe complexity associated to naturally fractured formations constrains reservoir engineers to use simplified versions of the Material Balance Equation for determining the initial hydrocarbon in place and predicting reservoir performance.

Accelerating-Rate Calorimeter (ARC), Ramped-Temperature-Oxidation (RTO), and Combustion Tube (CT) tests are used for screening and designing air injection processes for enhanced oil recovery. These tests use different size samples of reservoir materials, operating under different conditions, have different interpretation requirements, and yield different types of information. ARC data have been used to provide rapid screening of the suitability of (especially) high pressure light oil reservoirs for air injection. Small reservoir samples are used, air injection displacement efficiency is not captured, but they provide explicit quantitative oxidation rate information. RTO experiments use larger quantities of core and reservoir fluids and allow some fluid displacement and production. Due to the nature of this type of test, a much larger fraction of the oil is consumed compared to field application, and oxidation data over a broad range of temperatures is implicitly provided. Finally, combustion tube tests provide the closest dynamic analog to actual reservoir conditions and have the largest core and fluid requirement. This paper describes a systematic procedure used to consolidate the data from these tests into a robust kinetic model for the design and implementation of air injection processes in heavy oil mature fields. The model considers both low and high temperature oxidation reactions, thermal cracking, and the compositional changes that the oil undergoes. Application of the model at the field scale shows temperature levels, produced gas compositions, and fuel and air requirements comparable with those derived from the combustion tube tests.

During the last few years, research has been done on generalized material balance equations for conventional oil and gas reservoirs in order to improve the reservoir performance analysis. However, those equations are inappropriate for coal seam gas (CSG) reservoirs. To address this limitation, a generalized material balance equation (GMBE) for CSG reservoirs was developed. This work is based on a mathematical development and the straight-line method, published previously and widespread used for conventional reservoirs. Three validation examples of the proposed equation were designed. They show the new equation has the following advantages:it is applicable to CSG reservoirs in saturated, equilibrium, and undersaturated conditions,it is applicable to any type of coalbed without restriction on especial diffusion constant values,existent equations are particular cases of the generalized equation evaluated under certain restrictions, andits reorganization is analogous to the popular straight- line method for conventional reservoirs. P. 621

The PDF file of this paper is primarily in Spanish, with small portions of English text throughout the manuscript. A complete English version is not available. In Colombia the water injection process has been applied in 19 oil fields at a commercial level. The processes implemented normal and inverted patterns of 5, 7 and 9 points; some others were initially designed for pressure maintenance. In any injection process the volumetric sweep efficiency depends on the geology of the reservoir sands, type of sedimentary basin and on the mobility of the reservoir fluids, because of this, the incremental oil recovery factor of the Colombian field's water injection processes is between 1% and 9%. This paper presents the results of fillup, plateau, decline, secondary recovery efficiency and typical problems of processes in Colombian fields. The average oil recovery factor in Colombia is approximately 18%, around 90% of the 280 Colombian oil fields are still in primary production and many of them have a big loss of the reservoir energy. By the mentionned above, and with the objective of rising the oil production in the country, the implementation of waterflooding processes plays a fundamental role for both increasing the oil recovery factor and giving energy to the reservoirs for the implementation of any other technology that can increase the productivity of the wells. Today there are being designed and implemented an important amount of water injection projects. A significant percentage of Ecopetrol's production target in 2015 - 2020 depends on the implementation massive of the water injection process, this is why 27 new water injection processes have been stablished as a strategy to incorporate reserves, breaking historical rhythms of implementation. The generation of standards and best practices in the technical, operational, environmental, social, legal, implementation and surveillance aspects, has been identified as a key factor to ensure that the Company's know-how supports this goal, reducing implementation time and increasing quality and efficiency of new waterflooding pilots and expansions projects in Colombia.