绥中36-1油田水源井结垢产物与机理分析

A Study of Water Wells’ Scaling Products and Mechanism in SZ36-1 Oilfield

丁博钊 唐洪明 高建崇 朱 凯 崔 刚

DING Bo-Zhao TANG Hong-Ming GAO Jian-Chong ZHU Kai CUI Gang

绥中36-1油田水源水矿化度9548 mg/L，含Mg2+、Ca2+ 819.94 mg/L，注水管线结垢严重。通过偏光显微镜、扫描电镜、X-射线衍射仪检测表明，水源水在井下管柱、地面海管产出的钙质垢的晶形、晶粒大小、产状等均明显不同。井下管柱壁上的产出垢为方解石，晶形晶面完好，晶粒粗大，以镶嵌状、连晶状产出，垢产物包含的主要元素为O、Si、Ca、C，含少量Mg、Fe、S等，代表了储层温度、压强和未加阻垢剂条件下垢的特征；地面海管产出钙质垢为晶体大小不均、菱面体状的方解石晶体与针柱状的文石晶体互层，垢产物包含的主要元素为O、Ca、C，含少量Mg、Fe。结垢机理分析表明，阻垢剂阻断了文石向方解石的转化。油管、海管中钙质垢的特征对比为研究阻垢剂对晶体生长特征、阻垢机理提供了很好的矿场实例，为室内阻垢剂评价效果提供了佐证。

The source water salinity of Suizhong 36-1 oilfield was as high as 9548 mg/L, and the ion concentration of magnesium and calcium was of 819.94 mg/L. As a result, the problem of water injection line scaling was serious. The well scaling products were analyzed by ESEM, EDS and XRD. The results showed that the calcium carbonate scales which in the surface pipeline and the underground string were significantly different in crystal feature, granularity and shape. The scale produced from underground string was calcite, which had complete crystal shape and coarse grains. The main elements of scale products included O, Si, Ca, C and a small amount of Mg, Fe, S, etc. It represented the scale characteristics under the downhole conditions of pressure and temperature without the influence of scale inhibitor. The scale crystals produced from surface pipeline were calcite in form of crystal rhombohedron and aragonite in form of acicular and columnar shapes, both of which distributed alternately. The main elements of scale products included O, Ca, C and a small amount of Mg, Fe. This phenomenon showed that the scale inhibitor prevented aragonite from changing into calcite. The characteristics comparison of calcium carbonate scale in the surface pipeline and the underground string offered a typical case for the mechanism studies on influences of crystal growth characteristics by scale inhibitor.