Murtaza Mobeen, Kamal Muhammad Shahzad, Mahmoud Mohamed
Petroleum Engineering Department, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
ACS Omega. 2020 Jul 8;5(28):17405-17415. doi: 10.1021/acsomega.0c01777. eCollection 2020 Jul 21.
Shale swelling during drilling operations causes many problems mainly related to wellbore instability. The oil-based muds (OBMs) are very effective in controlling the swelling potential of clay-rich shale formation, but their environmental concerns and the economic aspects curtail their usage. In the application of water-based mud (WBM), it is mixed with various swelling inhibitors such as inorganic salts (KCl and NaCl), sodium silicate, polymers, and amines of various types. The above-mentioned materials are however afflicted by some limitations in terms of their toxicity, their effect on drilling mud rheology, and their limited tolerance toward temperature and oil contamination. In this study, we investigated a novel hybrid aqueous alkali alumino silicate (AAAS) as a shale swelling inhibitor in WBM. The AAAS is a mixture of sodium, aluminum, and silicon oxides. Experimental investigations were carried out using a linear swell meter, hot rolling and capillary suction timer, ζ-potential test, filtration test, and rheology test. The application of hybrid silicate as a swelling inhibitor was studied in two phases. In the first phase, only silicate solutions were prepared in deionized water at various ratios (1, 2, and 5%) and tested on sodium bentonite and shale samples containing high contents of kaolinite clay. Further testing on commonly used inhibitors such as KCl and sodium silicate solutions was conducted for comparative purposes. In the second phase, different drilling mud formulations consisting of various percentages of AAAS were mixed and tested on original shale samples. It was observed that the novel silicate-based mix proved to be a strong shale swelling inhibitor. Its inhibition performance was better as compared to the sodium silicate solution and KCl solution. It not only inhibits shale swelling but also acts as a shale stabilizer due to its high adsorption on the shale surface, which prevents the shale/water reactivity, makes the shale formation stronger, and prevents caving.
钻井作业期间页岩膨胀会引发诸多问题，主要与井壁稳定性相关。油基泥浆（OBM）在控制富含粘土的页岩地层的膨胀潜力方面非常有效，但其环境问题和经济因素限制了它们的使用。在水基泥浆（WBM）的应用中，它与各种膨胀抑制剂混合，如无机盐（KCl和NaCl）、硅酸钠、聚合物和各种类型的胺。然而，上述材料在毒性、对钻井泥浆流变学的影响以及对温度和油污染的有限耐受性方面存在一些局限性。在本研究中，我们研究了一种新型混合碱式铝硅酸盐（AAAS）作为水基泥浆中的页岩膨胀抑制剂。AAAS是钠、铝和硅氧化物的混合物。使用线性膨胀仪、热滚和毛细管吸入时间测定仪、ζ电位测试、过滤测试和流变学测试进行了实验研究。混合硅酸盐作为膨胀抑制剂的应用分两个阶段进行研究。在第一阶段，仅在去离子水中以不同比例（1%、2%和5%）制备硅酸盐溶液，并在含有高含量高岭土粘土的钠膨润土和页岩样品上进行测试。为了进行比较，还对常用抑制剂如KCl和硅酸钠溶液进行了进一步测试。在第二阶段，将由不同百分比的AAAS组成的不同钻井泥浆配方混合，并在原始页岩样品上进行测试。结果发现，新型的基于硅酸盐的混合物被证明是一种强大的页岩膨胀抑制剂。与硅酸钠溶液和KCl溶液相比，其抑制性能更好。它不仅抑制页岩膨胀，还由于其在页岩表面的高吸附性而起到页岩稳定剂的作用，这防止了页岩/水反应性，使页岩地层更强，并防止坍塌。
