Helmy Youssef, Fakher Sherif
Department of Petroleum and Energy Engineering, The American University in Cairo, New Cairo 11835, Egypt.
Materials (Basel). 2024 Jun 3;17(11):2710. doi: 10.3390/ma17112710.
The following study presents the results of research in the field of the performance of geopolymers consisting of Class F fly ash with an alkaline activator solution consisting only of sodium metasilicate (NaSiO) and water. The performances of this geopolymer are compared to the those of American Petroleum Institute (API) Class G cement. This comparison is to evaluate the potential of the geopolymer as an alternative to cement in cementing hydrocarbon wells in the oil and gas industry. The gap in the research is determining the performance properties that restrict the use of fly ash in the oil and gas industry. Using only sodium metasilicate as an activator with water, the solution creates a strong binding gel for the geopolymer and activates the aluminosilicate properties of the fly ash. This geopolymer is compared with Class G cement without additives to determine their base performances in high pressure and high temperature conditions, as well as note any properties that are affected in the process. This commences by formulating recipes of these two materials from workable ratios and concentrations. The ratios are narrowed down to the best working models to proceed to comparative performance testing. The tests included exploring their vital performances in fluid loss and thickening time. The results produced suggest that Class G cement generally has less fluid loss at low temperature than the geopolymer but could not maintain its integrity and structure as temperatures increased. Class G cement exhibited stability, consistencies of 100 Bcs (Bearden Consistency Units), and a faster thickening time of 1 h and 48 min when placed under high temperature and high-pressure conditions, respectively. However, the geopolymer showed more consistency regarding fluid loss with respect to rising pressure and temperature, and smoother, less fractured samples emerging from both tests. Though the geopolymer showed stronger performances in thickening and water retention, the experiments showed that it is not a uniform and consistent material like Class G cement. Through the use of different additives and intricate design, the sample may show success, but may prove more difficult and complex to apply than the industry standard and uniform content of Class G cement.
以下研究展示了由F类粉煤灰与仅由硅酸钠（NaSiO）和水组成的碱性活化剂溶液构成的地质聚合物性能领域的研究结果。将这种地质聚合物的性能与美国石油学会（API）G级水泥的性能进行比较。这种比较旨在评估地质聚合物作为石油和天然气行业油气井固井中水泥替代品的潜力。研究中的差距在于确定限制粉煤灰在石油和天然气行业使用的性能特性。仅使用硅酸钠作为活化剂与水混合，该溶液为地质聚合物形成了一种强粘结凝胶，并激活了粉煤灰的硅铝酸盐特性。将这种地质聚合物与无添加剂的G级水泥进行比较，以确定它们在高压和高温条件下的基本性能，并记录在此过程中受影响的任何特性。这首先从可行的比例和浓度制定这两种材料的配方开始。这些比例被缩小到最佳工作模型，以进行比较性能测试。测试包括探究它们在滤失和稠化时间方面的关键性能。结果表明，G级水泥在低温下的滤失通常比地质聚合物少，但随着温度升高，其无法保持完整性和结构。G级水泥表现出稳定性，稠度为100 Bcs（贝登稠度单位），在高温和高压条件下分别具有更快的稠化时间，即1小时48分钟。然而，地质聚合物在压力和温度升高时滤失方面表现出更高的一致性，并且在两次测试中都出现了更光滑、裂缝更少的样品。尽管地质聚合物在稠化和保水方面表现出更强的性能，但实验表明它不像G级水泥那样是一种均匀一致的材料。通过使用不同的添加剂和复杂的设计，样品可能会取得成功，但可能比G级水泥的行业标准和均匀成分更难应用且更复杂。
