Horizontal wellbore stability and sand production in weakly consolidated sandstones
Horizontal wellbore stability and sand production in weakly consolidated sandstones
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DOI：
10.2118/65755-pa
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发表时间：
2000-12
影响因子：
1.4
通讯作者：
P. V. D. Hoek;A. Kooijman;P. D. Bree;C. J. Kenter;Z. Zheng;M. Khodaverdian
中科院分区：
文献类型：
--
作者：
P. V. D. Hoek;A. Kooijman;P. D. Bree;C. J. Kenter;Z. Zheng;M. Khodaverdian
在弱固结至未固结砂岩地层（如墨西哥湾、尼日利亚）中，采用未胶结衬管的水平井眼完井的长期稳定性仍然是一个值得关注的问题。本文介绍了专门的多轴细胞实验室实验解决这个问题的结果。此外，还研究了近井地带岩石破坏对油井产能的影响。制备大块的弱人造砂岩。在这些区块中钻了一个孔，并模拟了在不存在和存在衬管的情况下，在各种地应力值、水位下降和含水率下的生产条件。在测试过程中，孔保持在水平位置，以真实地模拟重力对砂屑运动的影响。孔的失败和重新稳定的过程中，连续监测耦合到一个摄像机的内窥镜。实验结果表明，在存在割缝衬管的情况下，在没有含水的情况下，岩石破坏导致环空逐渐充满松散的沙子，最终导致稳定的配置，其中只有一小部分远场应力被转移到衬管。这些结果进一步支持弹塑性计算。已证明，衬管周围的岩石破坏对生产率只有很小的影响。这一结果意味着在井口通常不会注意到非水泥衬管完井周围的岩石破坏。引入少量（<5%）含水导致大量出砂和随后的衬管坍塌。这可以通过以下事实来解释：含水破坏了毛细管凝聚力，从而破坏了槽上砂拱的稳定性。«少
Long-term stability of horizontal wellbore completions with uncemented liners in weakly consolidated to unconsolidated sandstone formations (e.g. Gulf of Mexico, Nigeria) remains an area of concern. This paper presents the results of dedicated polyaxial cell laboratory experiments addressing this issue. In addition, the influence of rock failure in the near-wellbore region on well productivity was studied. Large blocks of a weak artificial sandstone were prepared. A hole was drilled in these blocks, and production conditions at various values of in-situ stress, drawdown and watercut, both in the absence and presence of a liner, were simulated. During testing, the hole was kept at a horizontal position in order to realistically simulate the influence of gravity forces on the movement of sand debris. The process of hole failure and restabilization was continuously monitored by an endoscope coupled to a video camera. The experimental results show that in the presence of a slotted liner, and in the absence of watercut, rock failure leads to a gradual annulus fill-up with loose sand, eventually resulting in a stable configuration in which only a small fraction of the far-field stresses is transferred to the liner. These results are further supported by elasto-plastic calculations. Rock failure aroundmore » the liner is shown to have only a minor effect on productivity. This result implies that rock failure around uncemented liner completions will generally not be noticed at the wellhead. The introduction of a small (<5%) watercut resulted in massive sand production and subsequent liner collapse. This can be explained by the fact that watercut destroys capillary cohesion, thereby destabilising sand arches over the slots.« less