The gas migration during the cementing of wells is one of the main problems of oil wellsengineering. Its occurrence can cause severe problems since shortly to loss of control of the well aftercementation. Recently, 20/04/2010 In an accident of major proportions in the Gulf of Mexico, amongother factors, faulty cementing operation provided the gas migration, causing the accident, in which 11people died and 17 were injured occurred. Besides the serious consequences that can be caused bygas migration, remediation of the problem, which is made by injecting cement in damaged areas,usually involves additional costs and is not always effective. Therefore, preventing gas migration to bepreferred. Some methods are used to prevent the migration of the pressurized gas as the annularspace, application of pressure pulses, reducing the height of the cement column compressible cementpastes of low permeability, pastes and to control free filtered water, and binders of thixotropic cementexpandable and flexible. Thus, the cement pastes used to prevent gas migration must meet themaximum these methods. Thus, this study aimed to formulate a cement paste to prevent gasmigration, using the expanded vermiculite, and evaluate the behavior of the folder trials necessary foruse in oil wells. Free water content, rheological properties, compressive strength, loss of liquid phasesedimentation of solids, specific weight, thickening time and gas migration: The following tests wereperformed. The results show that meets the specifications paste formulated for use in oil wells and theuse of expanded vermiculite contribute to the absorption of free water, thixotropy and low density. Theabsorption of free water is proven to result in zero percentage test free water content, thixotropy isobserved with the high value of the initial gel strength (Gi) in testing rheological properties and lowdensity is proven in test weight specific
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