The Preparation Of Resitstance To200℃Oil Well Cement Slurry

Cementing is the work to fix the oil pipe and the stratums after the hole built, andcementing is an important process to exploit the petroleum. For slices mined successivelywe must cementing, it’s also the fundamental for safe production.The cementing construction process is inject the prepared cement slurry to stratumsthrough the casing, at first. When the slurry arrive the casing bottom, it will upwardthrough the annular space, then all of the slurry will be injected to the annular with arubber stopper, then wait for the cement slurry solidification under static condition.The need for petroleum is continues to expand, with the development of economy.Now, exploit the deep petroleum is economy rationality. But, the earth’s crust hasgeothermal gradient, with the exploitation deeper the stratums hotter. In particular, thegeothermal gradient in Daqing is higher than the average levels. For example, thetemperature in the6000m depth will be200℃.At200℃, the cement slurry which was prepared for the cementing willsolidification rapidly, can not be injected to the target stratum. Even has the possibility tosolidify in the casing.To develop the exploitation ability and capture the main technical difficulty we mustimprove the heat-resistant property of the cement slurry. The admixture is the majormethod to improve the slurry ability, the retarder and the filtrate reducer are the mostimportant admixture. The retarder is used to keep the slurry’s flow ability, then the cementslurry can be injected to the aim safety. The filtrate reducer is used to reduce the slurryfiltration, avoid the slurry thicken immediately, then plugging the pipe. The admixture alsoincludes stabilizer, dispersant, set-controlling, etc.Some foreign drilling company have already developed the relative products whichcan resistant the200℃.For example, the Schlumberger’s UNIFLAC filtrate reducer canbe used to10～260℃, and less dosage, strong adaptability, the UNIFSET hightemperature retarder can be used to82～232℃,for brine and fresh water; Halliburton’sSCR-100, HR-25all can resistant exceed200℃, Latex2000latex can resistant193℃. But it’s blank in China. The products only can resistant180℃now. Over this temperature, wehave to buy the foreign products, it’s greatly increases the cost of cementing.This paper introduces the study in cement slurry solidification and the key way tocontrol this course. By the study we found:1. There lies in an exponential relationship between the hydration of cement and thetemperature.2. The pressure can less affect the hydration of cement3. The effect of complexant on the hydration of cement is complicated.4. By control the processes involved Calcium ion can effect the hydration of cementeffective.Though the understanding, we begin to the related research, at last we synthesis theretarder for oil well cement can resistance to230℃, thefiltrate reducer for oil well cementcan resistance to200℃. After the evaluation of the admixture, the results are satisfied.Then, we mixed the cement paste with them and evaluation the paste, we can conclude thepaste can be used to cementing the200℃deep well.