Maraven has evaluated the application of horizontal wells to enhance productivity and economics of their major heavy oil fields. Improving primary recovery on these heavy oil fields is important since it will allow postponing the implementation of more costly displacement processes such as steam drive.

Primary recovery includes not only Cold Production but also Cyclic Steam Stimulation (CSS). So far, two horizontal wells have been drilled in the Zuata area of the Orinoco Belt and four in the Bolivar Coast area. Several problems such as: sanding, completion design, formation damage and steam distribution have been reported. However, preliminary results show the benefits of the application of this technique in these heavy oil reservoirs.

Dead oil viscosity in these areas ranges from 1000 cp. to 20000 cp. at a temperature of 100°F. Cold production from a horizontal well is about 3 to 5 times the response of a vertical well, while the hot production rate is about 3 times of that reported from a steamed vertical well. The cost of a horizontal well is double the cost of a vertical well in the same areas, which makes a good net present value out of this project. Based on these results, plans have been laid down to extend the use of this technology.

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