Research On The Cementing Slurry System In Kenya's Geothermal Wells

The geothermal well cementing project in Kenya mainly faces the special situation of "three specialties",especially the high temperature,the special development of fractures and the special number of backfilling.This leads to the long construction period and poor cementing quality in this area,which is not conducive to improving the economic benefit and geothermal well It is necessary to carry out targeted analysis of cementing difficulties in the area,study the appropriate high temperature and low density and with the plugging function of the slurry,and the corresponding construction process parameters designed to be able to Kenya geothermal wells Cementing quality.In this paper,the problem of cementing in this area is collected,analyzed and researched by the basic data,and the anti-high temperature and low density leak-proof water-loss mud system is targeted to improve the cementing quality.Mainly include the following:The first,Based on the experimental and theoretical analysis,the basic materials of fly ash,micro-silicon and ultra-fine cement were selected,and the effects of high-temperature early strength agent,water-loss agent,retarder And quartz sand.The second,according to the properties of cement slurry,the content of each additive is studied experimentally,and the suitable cement slurry formula is selected to be applied to the geothermal well cementing in Kenya.Through the experimental research and theoretical analysis,1.65g/cm~3and 1.35g/cm~3cement slurry formulations were developed,respectively,suitable for different environments.The cement slurry of the indicators are able to meet the requirements of cementing,has a certain value.The third,the performance of high-temperature and low-density leak-proof cement slurry was studied.The optimum of cellulose was studied,and the related properties of cement slurry were also studied.Cellulose is inert material,the addition of 0.4%has little effect on the rheological properties of the cement slurry,preferably fiber B as 1.65g/cm~3and1.35g/cm~3low density cement slurry system plugging fiber,Plugging effect is relatively good.The fourth,with the addition of micro-silicon,the elastic modulus of cement paste decreases,Poisson's ratio increases,the compressive strength decreases slightly,but the effect is not significant.The decrease of elastic modulus of cement stone will improve the flexural strength and impact toughness of cement stone,which is of great significance for extending the life of oil and gas wells.The fifth,low-density cement slurry system by particle size distribution,reducing the permeability of cement stone,and the addition of fiber,because the fiber diameter smaller than the cement particles in the cement can be relatively fully dispersed,the fibers can be distributed in the cement The gap between the particles,blocking the voids of cement stone channel,making the permeability of cement stone reduced.The sixth,field application shows that the high temperature resistance and low density cement slurry system has good performance,to meet the high temperature easy to leak well cementing requirements,as soon as possible on-site geothermal field test.