Abstract
Cyclic steam injection is the most commonly used method to produce the heavy oil reservoirs in the Bolívar Coast in Western Venezuela. The efficiency of this method in this field, as measured by the oil to steam ratio, is remarkably high, mainly due to compaction drive. Nevertheless, later cycles show a natural decline in the efficiency of the process.
In order to improve the efficiency, and to extend the application of cyclic steam injection in the field, different types of additives are being tested. Laboratory study, and field tests were conducted in order to study the possible merits of the addition of small amounts of solvent as part of the injection process. On the other hand, due to the massive sand bodies, and shale intercalations that exist in the heavy oil reservoirs of the Bolívar Coast, foam was used in order to improve the vertical sweep efficiency of steam injection during huff’n puff.
After the conduction of laboratory experiments with steam/foam, a set of 16 wells were selected in order to test the injection of two commercial foaming agents (LTS and BBS). In this work, the field results of these pilot test of foam injection are analyzed, and correlated with several variables.
Four wells were stimulated with steam injection with solvent. The solvent used was an industrial diesel. As in the previous case, field results were analyzed. The merits of the process are obtained by comparing the response of the wells, with neighboring wells with similar characteristics. Prior to the field tests, laboratory experiments were carried out, in order to obtain the operating conditions.
