The Improvement Study On Cementing Evaluation Standard Based On Cement’s Acoustic Property

With the oil-gas exploration and exploit march toward difficult fields, such as deep well,low porosity and low permeability, high temperature and high pressure, deep water and lowformation fracture pressure and so on, and with the application of new cementingtechnologies and new cementing materials. Cementing quality evaluation is facing on seriouschallenge, the currently available cementing quality evaluation standard can not suitable someparticular situation.Therefore, the research of improving cementing quality evaluationstandard has important significance.Through analysis of casing wave propagation and energy decay process, established themodel of casing wave in cased well, this model can analyze the impacting of cement natureand the first interface cementing status on logging response, lay the foundation for improvingcementing quality evaluation standard.Measuring the cement stone’s acoustic property and strength property under differentconditions, found that temperature and retarder will affect the cement stone’s velocitydevelopment in early period, but in the middle-later period, the impact is not big; For a samecement slurry at a specific curing condition, the p-wave velocity and compressive strength isexponential relationship; The impact of lightening materials on acoustic property and strengthproperty is big, and the acoustic property is different between the different kind of low densitycement slurry.Through comparing the value of the casing wave‘s amplitude at need to be improvedcondition and the casing wave‘s amplitude of common cementing at different cementationstatus，can be well improving cementing quality evaluation standard. The calculation resultsshowed, the impact of temperature and retarder on cementing quality evaluation standard islittle, but the impact of lightening materials is obvious. The cementing quality evaluation standard after improved can accurately evaluate the cementing quality of different cementslurry system at different curing condition.Through Analyze the impact of waiting-on-cement time on cementing quality evaluationstandard，draw up a method to definite the optimal logging time，temperature and retarder arethe most important factors to influence the optimal logging time，and the thickening time，initial setting time，final setting time are positively correlated with the optimal logging time.