Effect of Shear Stress Buildup at the Interface of Sand Control Screen and Oil Sand on the Screen Performance in SAGD

蒸汽辅助重力泄油（SAGD）是加拿大稠油热采的主要技术。该技术采用两口水平威尔斯井，通过安装称为防砂设备（SCD）的筛管内衬来支撑水平井以防坍塌。SCD的设计目的是（1）控制出砂，同时允许储层流体流入井内;（2）允许排出细粒物质，以避免堵塞筛管和筛管后的孔隙空间。* SAGD项目的运营和资本支出很高。与SCD性能相关的问题，如过度堵塞，使加拿大石油工业花费了大量的时间和金钱。由于SCD性能预测缺乏确定性，行业通常选择保守、更昂贵的设计决策。随着最近油价的波动，避免不必要的成本对加拿大在当今石油市场保持竞争力至关重要。更好地了解SCD性能将有助于优化较便宜的完井（如割缝衬管）的设计，以提高其性能，避免昂贵的替代品并降低井筒干预成本。所提出的研究涉及SCD-地层界面处的剪切应力积累对出砂和堵塞的影响的基础研究。应力的建立主要是由于储层的热膨胀，这是由SCD的限制。假设是剪切应力通过破坏槽后沙桥的稳定而加剧出砂。目前，设计标准过于保守，导致要么使用昂贵的SCD（如绕丝筛管），要么在割缝衬管中使用较窄的缝，因此，增加了堵塞潜力，降低了井筒产能。假设SCD设计允许更宽的槽与滑动接头的安装相结合以减轻界面剪切应力，与使用不带滑动接头的较窄槽相比，该SCD设计导致类似的出砂量。使用较宽的槽减少了槽堵塞，并允许在衬管中切割较少数量的槽，因此，减少了SCD制造成本并提高了衬管完整性。* 改进的SCD设计预计将导致程序和技术的发展，从而提高井筒生产率，降低完井和修井成本，并降低由于产生少量污染砂而造成的环境影响。其结果是降低了重油生产行业的资本和运营支出，这将使加拿大工业在低油价下仍能竞争。对加拿大的另一个好处是对HQP的培训，这将促进测试方法，在关键领域创造科学和实践知识，并通过期刊和会议出版物传播。这些将帮助加拿大巩固其在科学和工程研发领域的前沿地位。

Steam Assisted Gravity Drainage (SAGD) is the main thermal technique for in situ heavy oil recovery in Canada. This technique employs two horizontal wells that are supported against collapse by the installation of screen liners called Sand Control Devices (SCDs). SCDs are designed to (1) control sand production while allowing the flow of reservoir fluids into the well; and (2) allow the discharge of fine materials to avoid plugging of the screen and pore spaces behind the screen.***SAGD projects have high operating and capital expenditures. Issues related to SCD performance, such as excessive plugging, cost the Canadian oil industry a significant amount of time and money. Due to the lack of certainty in SCD performance prediction, the industry often opts for conservative, more expensive design decisions. With recent volatility in oil prices, avoiding unnecessary costs is critical for Canada to remain competitive in today's oil market. A better understanding of SCD performance would help to optimize the design of less expensive completions, such as slotted liners, to improve their performance, avoid expensive alternatives and reduce wellbore intervention costs.***The proposed research is concerned with the fundamental investigation of the impact of shear stress buildup at the SCD-formation interface on sand production and plugging. The stress builds mainly due to reservoir thermal expansion, which is restricted by the SCD. The hypothesis is that the shear stress exacerbates sanding by destabilizing sand bridges behind the slots. Currently, design criteria are excessively conservative, resulting in either the use of expensive SCDs such as wire-wrapped screen, or the use of narrower slots in slotted liners, hence, increasing plugging potentials and lowering wellbore productivity. An SCD design which allows wider slots combined with the installation of slip joints to relieve the interface shear stress is hypothesized to result in similar amounts of sanding compared to the use of narrower slots without slip joints. The use of wider slots reduces slot plugging and allows a lower number of slots to be cut in the liner, hence, less SCD manufacturing costs and improved liner integrity. ***An improved SCD design is expected to lead to the development of procedures and technologies that result in higher wellbore productivity, lower well completion and workover costs, and lower environmental impact due to smaller amounts of produced contaminated sand. The outcome is lower capital and operating expenditures for the heavy oil production industry which will enable Canadian industries to compete despite low oil prices. Another benefit to Canada is the training of HQP that will advance testing methods, create scientific and practical knowledge in a critical area, and disseminate through journal and conference publications. These will help Canada to assert its position at the forefront of R&D in science and engineering.