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

蒸汽辅助重力排水(SAGD)是加拿大稠油原地开采的主要热力技术。这项技术采用了两口水平井，通过安装称为防砂装置(SCD)的筛管来支撑这两口水平井防止坍塌。SCD的设计目的是(1)控制出砂，同时允许油藏流体流入油井；以及(2)允许排放细物质，以避免堵塞筛网和筛网后的孔隙空间。 SAGD项目的运营和资本支出较高。与SCD性能相关的问题，如过度堵塞，花费了加拿大石油行业大量的时间和金钱。由于SCD性能预测缺乏确定性，业界通常选择保守的、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性能将有助于优化成本较低的完井设计，如开槽衬板，以提高其性能，避免昂贵的替代方案，并降低井筒干预成本。 这项研究是关于SCD-地层界面剪应力积聚对出砂和封堵影响的基础研究。应力的形成主要是由于储集层的热膨胀作用，而热膨胀作用又受SCD的制约。假设是剪切力通过破坏缝隙后面的砂桥的稳定而加剧了沙化。目前，设计标准过于保守，导致要么使用昂贵的SCD，如钢丝缠绕筛，要么使用狭缝衬里，从而增加封堵潜力，降低井筒产能。SCD设计允许较宽的槽与滑动接头的安装相结合，以缓解界面剪应力，假设与没有滑动接头的较窄槽的使用相比，会产生类似的砂磨量。使用更宽的槽减少了槽堵塞，并允许在衬里中切割更少的槽，因此，SCD制造成本更低，改善了衬里的完整性。 改进的SCD设计预计将导致开发程序和技术，从而提高井筒生产率、降低完井和修井成本，并由于产生的污染砂量较少而降低对环境的影响。其结果是重油生产行业的资本和运营支出减少，这将使加拿大各行业在油价低迷的情况下仍能竞争。加拿大的另一个好处是HQP的培训，这将改进测试方法，创造关键领域的科学和实用知识，并通过期刊和会议出版物传播。这些将有助于加拿大确立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.