Elasto-plastic fracturing model for wellbore stability using non-penetrating fluids
Elasto-plastic fracturing model for wellbore stability using non-penetrating fluids
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DOI：
10.1016/j.petrol.2004.07.006
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发表时间：
2004-12-15
影响因子：
--
通讯作者：
Belayneh, M
中科院分区：
文献类型：
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作者：
Aadnoy, BS;Belayneh, M
本文提出了一个适合于压裂实验的弹塑性压裂模型。该模型适用于钻井过程中使用的非渗透性流体，并假定井壁存在塑性区。最后一个方程是基于线性弹性-理想塑性材料特性。此外，提出了初始破裂和现有裂缝重新打开的模型。线弹性模型低估了空心混凝土芯上测得的破裂压力。该模型与实测数据吻合较好。研究发现，形成流体屏障的颗粒是关键因素，通过改变形成流体屏障的颗粒的组成，可以提高压裂压力，实验表明，可以通过设计钻井液来减少漏失问题。本文提出的模型将是这项工作的重要工具。为了建立一个屏障，一定的滤失是可取的。因此，粒度分布是一个关键参数。还发现，除了良好的滤液控制之外，屏障颗粒的机械强度控制破裂压力的最大值。实验表明，有可能几乎恢复失效井眼的初始断裂强度。(C)2004 Elsevier B.V.保留所有权利。
An elasto-plastic fracturing model that fits fracturing experiments is presented in this paper. This model is valid for non-penetrating fluids used during drilling operations.The model assumes a plastic zone at the borehole wall. The final equation is based on linear elastic-perfectly plastic material properties. Furthermore, models are presented both for initial fracturing and for reopening of existing fractures.The linear elastic model underestimate fracture pressures measured on hollow concrete cores. This new model fits well to the measured data. It is found that the particles forming the barrier are key factors, and it is front experiments observed that the fracture pressure can be increased by changing the composition of the particles forming the fluid barrier.Experiments have shown that it is possible to design the mud to reduce the circulation loss problem. The models presented in this paper will be important tools for this work.In order to establish a barrier, some filtrate loss is preferable. The particle size distribution is therefore a key parameter. It is also found that in addition to good filtrate control, the mechanical strength of the barrier particles control the maximum magnitude of the fracturing pressure. Experiments indicate that it is possible to nearly re-establish the initial fracture strength of a failed borehole. (C) 2004 Elsevier B.V. All rights reserved.