Research On The Cementing Quality Standard Evaluation Of Adhering Sand Casing Based On Energy Dissipation

With oil field entering the mid-late production period and the strength of the subdivision production increasing,the demand for cementing quality of adjustment wells is also getting more and more high.Adhering sand casing as the effective measure to improve the cementing quality is widely used in oil layer cementing construction.Relative to the application of adhering sand casing technology,the evaluation of adhering sand casing well cementing quality,which is still blank,remains adopting the smooth casing well cementing evaluation standard,and brings to the cementing quality interpretation unavoidable errors.In this paper,through analysis of logging acoustic wave transmission mechanism in the adhering sand casing well,with the change of acoustic wave energy in the transmission process being as the breakthrough point,the adhering sand casing well cementing quality evaluation standard based on the theory of energy dissipation was established.The specific research contents include the following aspects:First,the acoustic wave transmission mechanism in the adhering sand casing well was researched.Because of there are two layers of cementing agent and sand medium between the casing of adhering sand casing well and cement ring,the logging acoustic communication in adhering sand casing is more complicated than that in smooth casing well.Using acoustics theory knowledge,the logging acoustic travel path in drilling fluid-casing-cementing agent-sand-cement ring medium was analyzed,and the transmission mechanism of acoustic wave in the adhering sand casing well was researched,the types of acoustic wave received in adhering sand casing well were described exactly.Secondly,the energy dissipation of the logging acoustic waves transmitting in adhering sand casing was researched.According to the logging acoustic waves travel path in adhering sand casing well,the acoustic energy dissipation in space owing to the expansion of wave front,acoustic energy attenuation in the medium due to the viscosity,the heat conduction and relaxation absorption of the medium;the scattering attenuation of logging acoustic wave because of suspended particles in the drilling fluid and heterogeneity of the cementing layering medium and the energy loss of logging acoustic wave in drilling fluid-casing interface and casing pipe-cementing agent-sand-cement ring interface as a result of refraction were researced.Finally,according to the physical model of the adhering casing well borehole and the cementing layering medium boundary conditions,the acoustic field in adhering casing well borehole at different cementing conditions was solved,the amplitude of reflection wave that can actually reflect the cementing quality of adhering casing well was calculated,and then the standard for adhering sand casing well cementing quality was established.On the basis of this,the influence of sand particle diameter,adhering sand density,jointing compound composition and thickness on the cementing quality of adhering sand casing well interface I was analyzed.In this paper,the adhering casing well cementing quality evaluation standards were established by using energy method,which can improve the veracity of the adhering casing well cementing quality explanation,and enrich the theory of acoustic logging cementing quality,direct the adhering casing well cementing quality evaluation,and is a great significance of the popularization and application of the adhering sand casing.