Study On Experimental Method And Formulation Of Large Displacement Well Cement

Extended-reach well with high economic development value, it is widely used in the world. But Extended-reach well has larger horizontal displacement and deviation angle, resulting in poor cementing quality, oil, gas and water interfere with each other, seriously affected the implementation of well stimulation.Extended-reach well of free water movement and solid particle sedimentation in different ways in vertical wells. The performance test of extended-reach well cement slurry still follow the API standard, the laboratory test results and the actual results are not consistent. Also, the cement slurry formulations designed according to API standard can not meet the requirements of extended-reach well. Aiming at these problems, this paper carries on the study of extended-reach well cement slurry test method and formula.In order to simulate the extended-reach well environment, developed two sets of equip-ment:a set of inclined long barrel constant temperature water bath and the sediment-tube, a bong strength test device for extended-reach well. According to the special require-ments of extended-reach well cementing slurry, using the two sets of devices simulation environment for extended-reach well, select plastic expansive cement slurry system for sedimentation stability test, water separating test and bond strength test of different inclination and tempera-ture. Experiments show that the deviation angle of45°cement slurry sedimentation stability was the worst, and with the temperature rising increased cement slurry instability. The experi-mental method is recommended in the deviation angle of45°(or actual inclination) and bottom-hole circulating temperature (BHCT) evaluation sedimentation stability, water separa-tion, bong strength, compressive strength and permeability.Using slight expansion theory, fiber reinforced toughen theory and close packing theory, through the optimum additive and admixture adjustment plastic expansive cement slurry formulation, and evaluate the performance using the experimental method which is re-commended, the formation of extended-reach well cement slurry formulation with stability and good mechanical properties. Cement slurry has good antipollution thickening compati-bility, short transition time (the time of30-100Bc), appearing right angle coagulation and moderate anti-gas channeling ability. The performance evaluation and microscopic analysis of extended-reach well of cement of high side and low side, show that the difference is small, cement has good homogeneity.