伊朗雅达油田完井测试作业中沥青质析出分析

 伊朗雅达油田生产井由于沥青质析出和沉积在油管内壁，严重影响了油井的完井测试和投产前井下作业，例如阻碍钢丝作业工具的下入和井下工具的回收等。为了查清该油田原油中沥青质析出趋势和析出规律，结合雅达油田的特点，利用原油SARA 数据，采用胶体体系稳定性定量计算方法对沥青质析出程度进行了分析；采用热力学平衡原理和固体模型，结合不同产量下油管内温度与压力分布剖面，对沥青质析出初始压力与温度进行分析和预测，同时通过室内试验，评价并优化了沥青清除剂。通过对原油胶体体系稳定性定量计算，认为雅达油田原油胶体体系趋于不稳定，沥青质易于析出；通过对沥青质析出初始压力与温度及深度的预测，沥青质析出深度为2900~3700 m，认为雅达油田生产井自投产开始，沥青析出是无法避免的。室内沥青清除剂试验结果表明，单一的沥青清除剂无法达到满意的效果。在分析研究的基础上，优化了井筒处理方法和施工作业措施。

Asphaltene Precipitation Analysis in Well Testing in Yada Oilfield,Iran

The asphalt precipitation and deposition in the tubing inside wall have a serious impact on the well testing and the preproduction downhole operations in Yada oilfield, Iran, for example, they hinder the slickline tool running and the retrieving of downhole tools. In order to identify the asphalt precipitation and the precipitation trend and behavior in the crude oil, based on reservior characteristics in Yada oilfield, the asphalt precipitation extent is analyzed using a quantitative calculation for the colloidal system stability and the SARA data. Based on the thermodynamic equilibrium theory and the solid model, in combination with the predicted temperature and the pressure profiles inside tubing at different production rates, the initial pressure and temperature of the asphalt precipitation are analyzed and forecasted, and through laboratory testing, the asphalt scavengers are evaluated and optimized. The quantitative calculation results about the crude oil colloidal stability show that the crude oil colloidal system tends to be unstable and the asphalt separation is made easy. The predicted depth for the asphalt precipitation is in the range of 3000-3780 m, which indicates that since the beginning of the production wells the asphalt precipitation is unavoidable. Asphalt scavenger lab test results show that a single scavenger can not achieve satisfactory results, and an optimization for operation and treatment is proposed.