Study Of DZF-1Toughening Cement Slurry System

It is an important part for cementing operation during the drilling and completionprocess. The cement annulus which support the casing are fragile. There are manylow-pressure and leakiness wells in the Daqing oilfield. Cement slurry leakiness occurredduring the cementing operation. We study the cement slurry performance transformation byadding fiber material according to the actual problem of the cement slurry application duringthe cementing operation. We expected to improve the cement toughness and the leak-proofperformance of the cement slurry. The optimum fiber size was selected by enough experiment.The performance of cement stone including compression strength, rupture strength and tensilestrength were enhanced more than20%. Thus it can be seen, the fiber can improve themechanical properties remarkably. There was no breaking region around the cement annulusduring the perforating operation. All these proved that the fiber cement slurry system canenhance the cementation quality among the cement annulus, casing and borehole wall. So thefiber cement slurry system can cement the underground water, oil and gas layers and prolongthe well production life. In this paper, we study the thickening time, free fluid, fluid loss,stability of the cement slurry and the compression strength, rupture strength, tensile strengthvolume contraction of cement stone. The fiber cement slurry system improved thecompositive engineering performance. The experimental results show that it possessesexcellent characteristics as follows: easy to use, no adverse effect on other properties, bettercompatibility with other cement additives. We probed into the principles about improving thecement stone toughness and leak-proof function from macroscopical and microcosmic aspects.The fibers bear the Micro cracks in the cement stone. They deplete most applied force in orderto prevent the micro cracks continue to develop when the Micro cracks stressed. The fibersare adsorbed to the wall of structure and form web frame when the fibers leaked into thestratum with the cement slurry. The web frame prevents the cement slurry continuing to leakbecause cement slurry can fill the fiber web according to the particle composition and closepacking theory. The fiber cement slurry system has been applied in many wells in the Daqingoilfield and achieved good economic and social benefits.