大型碳酸盐岩油田沥青污染临界地层压力快速预测方法——以Buzurgan油田为例

Rapid Prediction Method For Critical Formation Pressure of Asphalt Contamination in Large Carbonate Oilfield:Take Buzurgan Oilfield as an Example

碳酸盐岩油田在海外油气资源中占有非常重要的位置,此类油田衰竭开发过程中由于地层压力下降沥青沉积现象普遍,严重影响油田正常生产。以伊拉克米桑Buzurgan油田为研究对象,基于该油田典型污染井动静态资料将碳酸盐岩油田生产井污染划分为三种模式,总结不同污染模式生产井的动态响应特征;基于油藏工程理论,综合考虑储层物性、流体性质、油井不同的含水情况、工作制度以及井筒结构对沥青污染程度的影响,建立了一套适用于碳酸盐岩油田的单井沥青污染临界地层压力快速预测方法。结果表明:(1)碳酸盐岩油田生产井污染原因不同,其动态响应特征也不相同;(2)酸化只能短期内达到恢复油井产能的目的,采取注水等开发策略维持合理地层压力水平才是实现此类油田高效开发的关键;(3)所建立的方法综合考虑实际生产中影响沥青污染的诸多因素,直接与油田现场相结合,为中国大型海外独资油田的高效管理提供有力的技术支持。

Carbonate oilfield plays a very important role in overseas oil and gas resources.Due to the decrease of formation pressure,the phenomenon of asphalt deposition during natural depletion is widespread,which seriously affects the production of oilfield.A large Middle East carbonate oilfield Iraq,Buzurgan oilfield was taken as an example,deeply analyzed dynamic and static data of the typically contaminated wells,divided the contamination type of production wells in carbonate oilfield into three modes,and concluded different modes of dynamic response characteristics among production wells.Based on reservoir engineering theories,considering reservoir and fluid properties,water cut status,working system combined with the impact of wellbore structure on asphalt contamination level,also established methods of predicting asphalt deposition critical pressure of production wells.Research shows as follows.①Carbonate oilfield production wells could be contaminated for different reasons and their dynamic response characteristics were different as well.②Acidizing operation could only achieve well productivity recovery in a short term,it is more crucial to take use of development strategies like water injection to maintain a reasonable formation pressure and realize the efficient development of such oilfields.③The method estabilished in this paper comprehensively considers many factors affecting the asphaltene pollution in actual production,and directly combines with field condition in order to provide powerful technical support for the efficient management of large solely invested oilfield oversea in China.