Exploration Of The Compatibility Of Cementing Fluids Under The Condition Of High-density Oil-based Drilling Fluids

With the rapid development of the petroleum industry,the exploration and development has gradually entered deeper formation,which is more complicated,which brings a lot of difficulties for drilling engineering.Due to the need of reality,many deep ultra deep well requires the use of oil base drilling fluid,although many advantages,but in the conventional cementing operation inevitably occurred two fluid contact mixed with oil-based drilling fluid and two fluid contact with contaminated produce sticky clumps of flocculent material,endanger the safety of cementing construction,cementing quality is difficult to guarantee,which cementing engineering brings a lot of problems.This paper taking the Tarim Piedmont grams deep block two wells as the object,a series of compatibility tests,including flow compatibility test,compressive strength compatibility experiment and thickening time compatible experiment loss compatible experiment and so on,through the experiments of mixed oil base drilling fluid and cement slurry mixing slurry compatibility research.ln addition,through the single factor analysis method,drilling fluid additive was added to the slurry,then tested under the condition of normal temperature and medium temperature fluidity and rheological parameters,and combined with infrared spectroscopy tester,XRD diffraction,scanning electron microscopy and atomic absorption spectrophotometry meter to carry out related experimental evaluation analysis,to study on drilling fluid in what kind of additives of cement slurry pollution,thereby optimizing drilling fluid performance to improve the compatibility of drilling fluid and cement slurry.The experiments were carried out to test the compatibility of 1.88 g/cm3 and 2.45g/cm3 oil based drilling fluid,spacer fluid and cement slurry.The experimental results show that the test results are good.CaCl2 and Versatrol(fluid loss additive)has a great influence on the rheological properties of the slurry,which makes it difficult to flow.Scanning composition analysis,XRD diffraction analysis and infrared spectral analysis showed that the chemical properties of cement paste and cement paste were not changed by the addition of CaCl2 and filtrate reducer.Thermoelectric applications iCE3000 atomic absorption spectrometer(USA)to investigate the cement paste,the conventional cement slurry,cement slurry with high density and respectively in the conventional cement slurry and high density cement slurry by adding CaCl2 and drop water loss of slurry changes in ion concentrations in the situation.The results show that:when the CaCl2,shorten the setting time of cement slurry,which leads to the reduction of the solution mainly Al3+ and Fe3+ concentration and CaCl2 solution in water,leads to the increase of the concentration of Ca2+;filtrate easy agent and cement hydration formation of Ca(OH)2 and the reaction occurs,accelerate cement hydration process,cause an increase in the solution of Ca2+,Al3+ and Fe3+,In addition,high density iron ore particles are very small,with a strong adsorption capacity,so that the concentration of ions in the solution to reduce.