海上油田采出污泥性质及其无害化处理方法研究——以SZ36-1油田为例

Properties of Sludge Produced from Offshore Oilfields and Its Harmless Treatment——an Example from SZ36-1 Oilfield

与陆地油田相比较，海上油田具有储层渗透率较高、非均质性较严重、岩石胶结强度较低和原油黏度较高等特点，水驱开发采收率较低。此外，海上油田操作费用较高，平台使用寿命较短，客观上要求加快开发速度。因此，早期注聚成为加快油田开发的重要技术措施。但由于注聚导致压力大幅度升高，进一步加剧了岩石结构破坏，采出液含泥量明显增加，这不仅造成平台油水分离系统工作效率降低，而且采出污泥无害化处理也成为海上油田亟待解决的技术难题之一。以油藏工程学、高分子材料学和物理化学为理论指导，以仪器检测、化学分析和物理模拟为技术手段，以SZ36．1油田储层和采出污泥为研究对象，开展了储层性质和污泥组成及其储层适应性研究，进行了污泥聚合物溶液调剖效果评价。结果表明，采出污泥由水、泥土颗粒和油组成，泥土颗粒大小不一、外观不规则，主要由氧、碳、硅等元素组成。当聚合物浓度0．06％～0.3％和泥土浓度小于0．6％时，由它们组成的污泥聚合物溶液可以满足泵送和储层大孔道封堵技术要求。与传统聚合物凝胶和颗粒类调剖剂相比较，污泥聚合物溶液不仅封堵强度高，而且成本较低，采出污泥回注地层是海上平台污泥无害化处理的有效途径。

Compared with onshore oilfields, offshore oilfields are characterized by high permeability of reservoir, serious heterogene- ity, low rock cementation, high viscosity of crude oil, and low recovery efficiency by water flooding. In addition, offshore oilfields are high in operation cost and short in service life of the platform. Therefore, it is necessary to accelerate development rate in early stage of polymer injection flooding. But due to the polymer injection, the formation pressure increased greatly, resulting in further damage in rock texture, and the mud content in produced liquid increased greatly. The work efficiency of oil-water separation system decreased due to high mud content in produced liquid. Therefore, it is urgent to treat harmlessly the sludge produced from offshore oilfields. Based on reservoir engineering, polymer materials and physica~ chemistry, study on reservoir properties, sludge composi- tion and its reservoir adaptability have been conducted by instrumental testing, chemical analysis and physical simulation, profile control effect of sludge polymer solution .The results show that withdrawn sludge is composed of water, clay particles and oil. The soil particles are not of uniform size and regular appearance, composed mainly of oxygen, carbon, silicon. When the polymer con- centration ranges from 0.06% to 0.3%, and mud concentration is less than 0.6%, the sludge polymer solution can meet the technicalrequirements of pumping and plugging large channels of reservoir. Reinjection of withdrawn sludge into formation is an effective way of harmless treatment of sludge, low in operation cost, high efficiency in plugging compared with the traditional polymer gel and particle profile control agents.