METHOD FOR CEMENTING THE CONDUCTOR, A TECHNICAL COLUMN DURING THE CONSTRUCTION OF WELLS Russian patent published in 2023 - IPC E21B43/14 

FIELD: oil and gas industry.

SUBSTANCE: proposed invention relates to the oil and gas industry, to a method for cementing a casing string, namely a conductor, a technical string in a wellbore. The invention is applied to complex mining and geological conditions, where the geological section under the conductor, the technical column is represented by fractured and cavernous rocks, characterized by intense or complete absorption of the drilling fluid, with partial circulation or its complete absence when drilling the wellbore. The method for cementing a casing string, namely a conductor, a technical string, in difficult mining and geological conditions includes direct and reverse injection of cement slurry. Before injection in the reverse way, the presence of injectivity of the space between the casing string and the well wall is determined through the counter cementing device. With the direct method for injection, a buffer liquid and a normal density cement slurry are sequentially pumped, and with the reverse method, a plugging system with instant filtration and a normal density cement slurry are sequentially pumped. Cement slurry during re-injection is pumped until the annulus is filled up to the wellhead, performing all stages within one technological operation without waiting for solidification after direct injection.

EFFECT: improving the quality of cementing in complex mining and geological conditions, which is determined by the quality of the contact of the cement stone with the casing string based on the interpretation of acoustic cement logging.

1 cl, 2 ex