Abstract

Maximizing the return on investment (ROI) of drilling and operating wells is one of the primary objectives of the extra-heavy oil exploitation project in the Neogeno Samaria field. This project pioneers the application of cyclic steam injection as an enhanced oil recovery method in Mexico. One of the keys to achieving this goal has been the acquisition of injection and pressure-temperature profiles logged during phases of the well's operating cycle (initial, injection, soak, production). This data has provided a better understanding (and thus, a more accurate assessment) of the effective distribution of the injected steam in the different sand bodies that make up this fluvio-deltaic depositional environment. In this area, each drilled well might cross several zones with different potential and characteristics, which affect the well's capacity for injected steam admission when the zones are simultaneously stimulated.

Although there are precedents for such operations performed in other countries, the operating conditions of the Samaria project present new technological challenges. Not only does the area have higher temperatures (reaching up to 315°C [600°F]) than other areas where similar projects are run, during this project, steam is injected through the tubing where the tool is run in hole, which affects the performance of the surface pressure control equipment. These problems were addressed with the development of new devices. The logs allowed adjustments to the well completion designs to achieve better distribution of the injected steam and extend the duration of the producing stage. The logs also aided selection of the optimal number of sands to be produced in each well, evaluation of well performance through several cycles of injection, identification of some effects of interference between wells and water/steam channelings, and more applications. This paper reviews some of these applications.

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