油藏开发中沥青质沉积机理及理论研究进展

沥青质作为原油中最复杂的固体成分，因其多样的分子结构和分子量，极易受到各种因素的影响，从而导致失稳和沉积。为了构建在油藏开采中规避沥青质沉积的操作指南，对国内外关于沥青质沉积实验和模拟的研究进行了回顾和总结。从沥青质沉积阶段出发，可以将沉积过程依次划分为析出、絮凝和沉积3个阶段，并对稳定性评价方法进行了简要概述。从流体性质（包括沉淀剂类型、原油组分和黏度）、储层性质和开采工艺（包括温度、压力、流速和开发方式）等方面详细论述了影响沥青质沉积的因素。结果表明，采用光学显微镜法和光散射法可以准确获取沥青质沉积的临界条件，再结合沥青质沉积热力学模型（包括溶解度和胶体模型）可以对开发过程中的沥青质沉积进行有效预测。其中，统计缔合流体理论的PC-SAFT状态方程考虑了沥青质颗粒的极性及关联性，能相对准确地模拟沥青质的相行为。针对沥青质沉积室内实验和数值模拟研究中存在的问题，未来沥青质沉积研究的可能方向主要为准确测定沥青质分子量及结构、建立通用的沥青质相平衡方程以及明确储层岩石中沥青质沉积机制及模型3个方面。该研究成果为深入剖析沥青质的沉积机理、完善沥青质沉积理论、攻克疑难杂症提供了参考和指引。

Research Progress on Asphaltene Deposition Mechanism and Theory in Reservoir Development

Asphaltene，as the most complex solid component in crude oil，is highly susceptible to various factors due to its diverse molecular structure and weight，leading to instability and deposition. In order to establish operational guidelines for avoiding asphaltene deposition in oil reservoir exploitation，a review and summary of research on asphaltene deposition experiments and simulations both domestically and internationally were conducted. Starting from the deposition stage of asphaltene，the deposition process could be divided into three stages：precipitation，flocculation and deposition. Then a brief overview of stability evaluation methods was provided. The factors affecting the deposition of asphaltene were discussed in detail from the aspects of fluid properties （including types of precipitants，crude oil components and viscosity），reservoir properties，and production processes（including temperature，pressure，flow rate and development method）. The results showed that the critical conditions for asphaltene deposition could be accurately obtained using optical microscopy and light scattering method. And then combined with thermodynamic models of asphaltene deposition（including solubility and colloid models），effective predictions could be made for asphaltene deposition during the development process. Among them，the PC-SAFT equation of state for statistical association fluid theory considered the polarity and correlation of asphaltene particles，which could relatively accurately simulate the phase behavior of asphaltene. In response to the problems in indoor experiments and numerical simulations of asphaltene deposition，the possible directions for future research on asphaltene deposition were mainly to accurately determine the molecular weight and structure of asphaltene， establish a universal asphaltene phase equilibrium equation，and clarify the mechanism and model of asphaltene deposition in reservoir rocks. This research achievement provided reference and guidance for in-depth analysis of the deposition mechanism of asphaltene，improvement of asphaltene deposition theory，and overcoming difficult and complex problems.