Hybrid Modeling of Sand Production from Petroleum Wellbore

本研究旨在开发一种实用可靠的石油井筒出砂预测工具。出砂是砂随储层流体流动的一种生产现象。据估计，砂磨每年花费该行业数十亿美元（例如，通过生产设施的侵蚀）。另一方面，少量的出砂可以通过去除例如由钻井期间的地层损害产生的井筒表皮来提高井筒生产率。 有两种类型的井眼完井：（1）防砂，其中不允许出砂;（2）防砂管理，其中允许甚至鼓励少量出砂。防砂成本高且降低生产率。出砂管理降低了完井成本，提高了产能，但需要在完井和井筒操作设计期间进行可靠的出砂预测。 目前，有几种模型用于评估砂率，其工作基于连续或非连续力学。基于连续体的模型在分析出砂方面很差。结果是虚假的依赖于数值网格设计。基于间断面的模型更准确地模拟出砂，但计算要求高，不适合现场规模的应用。 在这项研究中，将进行连续和间断为基础的方法的链接，以利用每个模型的最佳方面。不连续描述将用于井筒附近区域，在该区域，通过岩石中裂缝和裂隙的发展，预计会产生广泛的不连续响应，并且在该区域，沙子被调动。更远的地方，将利用连续介质描述，因为岩石响应可以通过连续介质力学精确描述。这种方法能够开发一个准确，可靠的模型，用于评估出砂率，可用于在现场规模的实际应用。

This research focuses on developing a practical and reliable tool for predicting sand production from petroleum wellbores. Sanding is a production phenomenon where sand flows with reservoir fluids. Sanding is estimated to cost the industry billions of dollars every year (e.g., through erosion of the production facilities). On the other hand, a small amount of sanding can improve wellbore productivity through removing the wellbore skin created, for example, by formation damage during drilling. There are two types of wellbore completion: (1) sand control in which no sanding is tolerated, and (2) sand management in which small quantities of sanding are allowed or even encouraged. Sand control is costly and reduces productivity. Sand management reduces the completion costs and enhances productivity, but requires reliable sand prediction during completion and wellbore operation design. Currently, there are several models for assessing sand rate, which work based on either continuum or discontinuum mechanics. Continuum-based models are poor at analyzing sanding. The outcome results are spuriously dependent on the numerical mesh design. Discontinuum-based models simulate sanding more accurately, but are computationally demanding and poorly suited for field-scale applications. In this research, linkage of the continuum- and discontinuum-based approaches will be carried out to take advantage of the best aspects of each model. The discontinuum description will be utilized for the near-wellbore area where extensive discontinuum response is expected through the development of cracks and fissures in the rock and where sand is mobilized. Farther away, a continuum description will be utilized as the rock response can be accurately described by continuum mechanics. This approach enables the development of an accurate, reliable model for assessing the sanding rate that can be used in practical applications at the field scale.