The Study and Property Evaluation of a Lipophilic Cement Slurry With LQ Emulsion

Wells drilled by using oil-based drilling fluids may have thin oil films attached to the sidewall and the casing, so low a cementation strength may be expected on annular interfaces during cementing. To solve this problem, the lipophilic properties of cement slurries have been modified through polymerization of lipophilic monomers and hydrophilic monomers through emulsion polymerization to generate LQ emulsion with desirable properties. During the process, soft carboxylic monomers dissolvable in unsaturated oil and rigid unsaturated olefin monomers were used as lipophilic monomers. By adding optimal stabilizers, lipophilic cement slurries with LQ emulsion were generated. Test results show that the slurry has an API filtration loss of no more than 50 ml, an adjustable thickening time of 150-300 min. and compressive strengths over 18 MPa in 48 hours. All these properties can meet the requirements of field cementation operations. LQ emulsion can form hydrophobic and lipophilic film inside and on surface of the cement. When in contact with oil film, the hydrophobic and lipophilic film may absorb oil then expand. In this way, the cementation strength in annular interface with oil film can be enhanced effectively. Test results show the lipophilic cement slurry prepared from LQ emulsion can be used in field cementation operations to enhance cementation strength of annular interfaces with oil films attached.