Heavy slurry pumping is facing enormous problems concerning pressure generation and casing limitations. Pumping high-density cement throughout narrow column, throttled at their extremity by the float equipment will generate more pressure, and could push casing to their limits of utilization. There are numbers of phenomena that could lead to casing length change as: piston, ballooning, temperature, tension and buckling. This work is oriented to study buckling effect on total casing length change. Generally, in conventional wells cementing, down hole conditions are referred to geological formation fracture pressure limit, which is lower than buckling limit. Heavy slurry displacement could make an exception, where buckling could appears at pressure inferior to geological fracture limit. While pumping heavy cement down, pressure inside casing increases progressively, pushing casing to extend, consequently risk of closing the narrow space out between casing and open hole total depth may appears. At this moment, buckling begins; pressure rise intensely to reach geological fracture limits and causes down hole loses. After passing the critical high pressure situation, casing will come back to their initial form. In order to overcome this situation, maximum allowable pressure during displacement together with problem indicators is proposed, to prevent and early detect the problem. Experimental and simulation results confirm the usability of assumption proposed.

中文翻译：

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大量泥浆置换过程中的最大允许压力

大量的泥浆泵面临着有关压力产生和套管限制的巨大问题。在整个窄柱上泵送高密度水泥，并通过浮球设备在其末端进行节流，这将产生更大的压力，并可能将套管推向极限。可能导致套管长度变化的现象有很多，例如：活塞，膨胀，温度，张力和屈曲。这项工作旨在研究屈曲对套管总长度变化的影响。通常，在常规的固井中，井下条件称为地质构造破裂压力极限，该极限低于屈曲极限。严重的泥浆位移可能是一个例外，在低于地质裂缝极限的压力下会出现屈曲。在泵送重水泥的同时，套管内部的压力逐渐增加，推动套管伸展，因此可能出现封闭套管与裸眼总深度之间的狭窄空间的危险。这时，屈曲开始了。压力急剧上升以达到地质裂缝极限并导致井下损失。通过临界高压情况后，套管将恢复其初始形状。为了克服这种情况，提出了位移期间的最大允许压力以及问题指示器，以防止和及早发现问题。实验和仿真结果证实了所提出假设的可用性。压力急剧上升达到地质裂缝极限并导致井下损失。通过临界高压情况后，套管将恢复其初始形状。为了克服这种情况，提出了位移期间的最大允许压力以及问题指示器，以防止和及早发现问题。实验和仿真结果证实了所提出假设的可用性。压力急剧上升达到地质裂缝极限并导致井下损失。通过临界高压情况后，套管将恢复其初始形状。为了克服这种情况，提出了位移期间的最大允许压力以及问题指示器，以防止和及早发现问题。实验和仿真结果证实了所提出假设的可用性。