矿场地表管线结垢物的物相组成分析

Mineralogy of Scaling in Oil Pipelines of Oilfields

管道结垢现象是困扰油田生产的重要问题之一,利用扫描电子显微镜观察、X射线衍射分析和X射线荧光分析等多种分析技术研究了矿场地表输油管线腐蚀和结垢的物相组成特征及其空间分布,发现管道结垢物包括富铁矿物(硫化物、氧化物和氢氧化物)和盐类矿物两类(重晶石、天青石和方解石等),并观察了管道内壁表面的腐蚀现象,结垢位于腐蚀部位内侧。推测这些结垢物的形成主要与硫酸盐还原菌(SRB)和化学沉淀有关。铁硫化物Fe9S8指示存在有SRB引起的微生物腐蚀作用,SRB的代谢产物在腐蚀部位周围堆积,宏观表现为点蚀。推测富铁结垢物的铁质主要来自管道腐蚀,而盐类结垢物则与油田卤水在地表的温度、压力和盐度变化有关。

Scaling is one of the serious problems disturbing the production of the petroleum.The mineralogy and spatial distribution of scaling in the surface of oil pipelines were studied by employing scanning electronic microscopy,X-ray diffraction and X-ray fluorescence spectra.The analysis discloses that scale is mainly composed of iron-enriched minerals（iron sulfide,oxide and hydroxyle）and salts（barite,celestite and calcite）.The erosion on the inner wall of the pipeline was observed,and the coexisting of scaling and corrision was also disclosed.It is deduced that scaling is resulted from the sulfate reduction bacteria（SRB）activities and chemical precipitation.The occurrence of the sulfide of Fe9S8 represents the corrision induced by SRB,which is presented as pit corrision.It is proposed that iron in the scale was derived from the corrision of the inner pipeline walls and the salts precipitated from the transported brine,and was resulted from the changes in temperature,pressure and salinity.