Asphaltene Precipitation and Deposition from Conventional Crude Oils

沥青质是原油中最重的部分，随着温度、压力或成分的变化，沥青质会沉淀，有时会形成沉积物。沥青质在油田设施中的沉积导致了生产损失和高处理成本。为了避免或减轻沉积，需要降水和沉积过程的数据和模型。这项研究计划的目标是现有数据和模型中的两个空白，这两个空白与更深的储层有关，比如纽芬兰近海发现的储层，以及二氧化碳淹没的储层，其中一些储层位于加拿大西部。*******缺口1 -溶解气体引起的沉淀：减压常规油的沥青质沉淀与溶解气体含量密切相关。然而，不同的溶解气体，特别是甲烷和二氧化碳的作用还没有被系统地研究过。建议在一定的温度和压力下，测量与甲烷、二氧化碳（和庚烷，如果需要强制沉淀）混合的死油的沥青质沉淀。这些数据将用于确定溶解气体的溶解度参数，作为相位行为模型的输入。现有的相行为模型将根据需要进行调整以表示数据。结果是一个经过数据验证的相行为模型，适用于所有常规石油应用中的沥青质沉淀。*******Gap 2 -高温下开放流中的沉积：大多数沥青质沉积研究都是在低温下进行的，而海上生产中遇到的高温沉积（高达130摄氏度）尚未得到严格的研究。沥青质通常被认为是沉淀的玻璃状颗粒，会絮凝并可能沉积。然而，这些颗粒实际上是一种富含沥青质的相，在较高的温度下会变成液体。因此，在较高的温度下，沉积过程会发生变化。建议设计并投入使用一种装置来研究深层储层温度和压力下的沥青质沉积。沉积机制将被提出，并根据该装置收集的数据进行测试，结果将被纳入沉积模型。*******提出的沉淀模型将允许作业者避免或计划沥青质沉淀，以维持生产，并可能避免或降低处理成本。这些模型将适用于任何深层或气驱油藏的操作人员。拟议的沉积研究可用于评估新的海上或气驱开发是否以及在何处可能遇到沉积问题。这是保证流动和减缓流动的关键第一步。拟议的研究还将支持两名博士生，他们将获得适合石油工业和学术界研究工程师职业的背景和培训

Asphaltenes are the heaviest fraction of crude oils and can precipitate and sometimes form deposits upon a change in temperature, pressure, or composition. Asphaltene deposition in oilfield facilities leads to production losses and high treatment costs. Data and models for the precipitation and deposition process are required to avoid or mitigate deposition. This proposed research program targets two gaps in the available data and models that are of relevance for deeper reservoirs, such as those found offshore Newfoundland, and for carbon dioxide flooded reservoirs, some of which are found in Western Canada.*******Gap 1 - Precipitation Caused by Dissolved Gases: Asphaltene precipitation from depressurized conventional oils is strongly dependent on the dissolved gas content. However, the roles of the different dissolved gases, particularly methane and carbon dioxide, have not been systematically investigated. It is proposed to measure asphaltene precipitation for dead oils mixed with methane, carbon dioxide (and heptane if required to force precipitation) over a range of temperature and pressures. The data will be used to determine solubility parameters for the dissolved gases to be used as inputs for a phase behavior model. Existing phase behavior models will be adapted as required to represent the data. The deliverable is a data validated phase behavior model for asphaltene precipitation in all conventional oil applications.*******Gap 2 - Deposition in Open Flow at Elevated Temperature: Most asphaltene deposition studies have been performed at low temperature and deposition at the higher temperatures encountered in off-shore production (up to 130C) has not been rigorously investigated. Asphaltenes are commonly considered to precipitate as glassy particles that flocculate and potentially deposit. However, the particles are in fact an asphaltene-rich phase which becomes a liquid at higher temperatures. Hence, the deposition process will change at higher temperatures. It is proposed to design and commission an apparatus to investigate asphaltene deposition at deep reservoir temperatures and pressures. Deposition mechanisms will be proposed and tested against the data collected in this apparatus and the results will be incorporated into a deposition model.*******The proposed precipitation models will allow operators to avoid or plan for asphaltene precipitation to sustain production and potentially avoid or reduce treatment costs. The models will be of use to any operator of a deep or gas flooded reservoir. The proposed deposition research can be used to assess if and where a new off shore or gas flood development is likely to encounter deposition problems. This is the crucial first step in flow assurance and mitigation. The proposed research will also support two Ph.D. students who will receive background and training suitable for careers as research engineers in the oil industry and academia.**