First Experience in the Application of Radial Perforation Technology in Deep Wells

Abstract

Abstract This paper describes the first application of radial perforation technology with hydraulic jet and coiled tubing in deep wells with complex geometry. Radial perforation technique utilizing hydraulic energy is being used in different places around the world with good results. Its main application is intended for marginal fields, with low productivity and shallow wells with depths between 1000m and 2000m, normally having simple geometry. Basically, several perforations can be made with this technology, in an existing well (mother well), perpendicular to the well axis and at several productive levels, thus improving the production profile around the main well or mother well. Repsol YPF Bolivia has adopted this technology to perform a pilot test in fields with good to moderate recovery and in deep wells with complex geometry (directional wells with depths between 3500m and 3900m). This operation was performed in three wells (Surubi A1, Paloma C7 and Surubi Bloque Bajo 109) in the Mamore Block in Bolivia. The main challenge for this operation was to adapt equipment and tools used up to that time, to much more severe operational conditions due to greater depths, tortuosity, type of formations to be drilled and mechanical conditions of the wells. The main subjects covered by this paper are:IntroductionCharacteristics of the reservoir and objectives for the application of this technology.Geometrical and mechanical characteristics of the wells. Operative results.Description of the equipment and main adaptations to new operative conditions.Main problems encountered. Solutions. Operative limitations.Conclusions. The results indicate that this technology may continue being an attractive substitute for other stimulation techniques, such as fractures, acids, side tracking, etc, even with higher costs implied by its application to complex wells and with the improvements that will definitively be applied to current tools and equipment 1- Introduction The permanent quest to increase productivity in low recovery wells has been a very good incentive for the development of new technologies to solve the economic equation in marginal fields. In some cases, such technologies may have the characteristics needed for other applications, with different requirements, however generating results similar to those for which they were originally designed. The specific case of the radial perforation system with coiled tubing using hydraulic energy and its application to deep wells is an example. This technique and the associated equipment were created and designed for application in marginal fields and shallow wells with simple geometry. In the practical operation this represents low degree difficulty and reduced cost operations. This paper details the application of this system but applying the same to non marginal fields and deep wells with complex geometry, representing operations with a high degree difficulty and high costs. Evidently, under such conditions, these projects represent a major investment risk, particularly when "adapting" a system to more severe conditions than originally designed for.