Performance of Oil-Based Cement Slurry as a Selective Water-Plugging Agent in High-Temperature and High-Salinity Cave-Fractured Carbonate Reservoirs

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• 作者：Cheng-Dong Yuan ; Wan-Fen Pu ; Fa-Yang Jin ; Yu-Chuan Zhang ; Hu Jia ; Tian-hong Zhao
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：April 9, 2014
• 年：2014
• 卷：53
• 期：14
• 页码：6137-6149
• 全文大小：763K
• 年卷期：v.53,no.14(April 9, 2014)
• ISSN：1520-5045

文摘

Excessive water production has been one of the most pressing issues facing oilfields worldwide. The low-level success rate caused by complicated well and reservoir conditions drives the development of an effective selective blocking agent that is suited to a simple plugging technique. In this study, we present a novel selective blocking agent that is oil-based cement slurry (OBCS) mainly composed of 0#diesel, crude oil, class G oil well cement, silica fume, a wetting and dispersing agent (sodium alcohol ether sulfate (AES)), and a retarder GH-9 (a copolymer of 2-acrylamido-2-methyl propane sulfonic acid and itaconic acid). The effectiveness of AES and the compatibility of AES and GH-9 when coexisting in the suspension system were investigated by microscopic experiments. The hydrated phases of the OBCS at 130 掳C and high salinity (210鈥?00 ppm) formation water were analyzed by X-ray powder diffraction (XRD). Thermogravimetry/differential scanning calorimetry (TG/DSC) was employed to study the products and content (mainly calcium hydroxide (CH)). The water-plugging performance of the OBCS was studied by carrying out core physical simulation experiments. XRD analysis reveals the presence of CH, calcium silicate hydrate (two types, Ca₂SiO₄H₂O and Ca₆Si₃O₁₂H₂O), ettringite, killalaite, and Xonotlite. Although TG/DSC analysis fails to calculate the content of CH as expected, it gives an indication that oil exists in the set cement. The results of the microscopic experiments show a good effectiveness of AES and compatibility of AES and GH-9. High-quality plugging performances were observed in core physical simulation experiments. The properties tested indicate that the OBCS is a promising prospect as a selective blocking agent for water treatment in high-temperature and high-salinity cave-fractured carbonate reservoirs.