Ebrahimi Mohammad, Ghalenavi Hossein, Schaffie Mahin, Ranjbar Mohammad, Hemmati-Sarapardeh Abdolhossein
Department of Petroleum Engineering, Shahid Bahonar University of Kerman, Kerman, Iran.
Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development, Ministry of Education, Northeast Petroleum University, Daqing, 163318, China.
Sci Rep. 2024 Dec 30;14(1):31679. doi: 10.1038/s41598-024-80893-2.
Because a significant portion of oil remains in carbonate reservoirs, efficient techniques are essential to increase oil recovery from carbonate reservoirs. Wettability alteration is crucial for enhanced oil recovery (EOR) from oil-wet reservoirs. This study investigates the impact of different substances on the wettability of dolomite and calcite rocks. The substances include silicon dioxide (SiO) and iron oxide (FeO) nanofluids, gelatin biopolymer, surfactants (sodium dodecyl sulfate (SDS)), FeO/SDS, seawater, and salt solutions (sodium chloride (NaCl) and calcium chloride (CaCl)). Initially, water-wet rocks were exposed to crude oil for 22 days, resulting in significant contact angle changes. Dolomite and calcite contact angles increased from 56.50° and 50.70° to 107.70° and 104.00°, respectively, due to the presence of heavy and polar elements in the oil. The impact of aging time (7 and 11 days) on rock wettability was studied. Oil-wet rocks were treated with SiO and FeO nanofluids and SDS surfactants for 11 days. The contact angles of the treated rocks decreased significantly. For instance, the contact angles of dolomite and calcite treated with SDS surfactants decreased to 39.07° and 27.38°, respectively, indicating water-wet conditions. Dolomite and calcite surfaces aged with gelatin decreased the contact angles to 38.40° and 34.52°, respectively. Treatment with SiO nanofluid reduced the contact angles of dolomite and calcite to 54.27° and 53.17°, respectively, while treatment with FeO nanofluid decreased the contact angles to 46.08° and 51.16°, respectively. Using FeO/gelatin nanocomposite resulted in contact angles of 26.00° for dolomite and 24.10° for calcite. The wettability alteration mechanism in nanofluids is attributed to structural disjoining pressure. Additionally, NaCl and CaCl solutions induced water-wet conditions, known as the salting-out effect, on dolomite and calcite specimens. Consequently, this study demonstrates the potential of various substances, such as nanofluids, surfactants, and salt solutions, to modify rock wettability and improve conditions for enhanced oil recovery.
由于相当一部分石油仍留在碳酸盐岩储层中，因此高效技术对于提高碳酸盐岩储层的石油采收率至关重要。润湿性改变对于油湿储层的提高采收率（EOR）至关重要。本研究调查了不同物质对白云石和方解石岩润湿性的影响。这些物质包括二氧化硅（SiO）和氧化铁（FeO）纳米流体、明胶生物聚合物、表面活性剂（十二烷基硫酸钠（SDS））、FeO/SDS、海水以及盐溶液（氯化钠（NaCl）和氯化钙（CaCl））。最初，水湿岩石暴露于原油中22天，导致接触角发生显著变化。由于原油中存在重质和极性元素，白云石和方解石的接触角分别从56.50°和50.70°增加到107.70°和104.00°。研究了老化时间（7天和11天）对岩石润湿性的影响。油湿岩石用SiO和FeO纳米流体以及SDS表面活性剂处理11天。处理后岩石的接触角显著降低。例如，用SDS表面活性剂处理的白云石和方解石的接触角分别降至39.07°和27.38°，表明处于水湿条件。用明胶老化的白云石和方解石表面的接触角分别降至38.40°和34.52°。用SiO纳米流体处理使白云石和方解石的接触角分别降至54.27°和53.17°，而用FeO纳米流体处理使接触角分别降至46.08°和51.16°。使用FeO/明胶纳米复合材料使白云石的接触角为26.00°，方解石的接触角为24.10°。纳米流体中的润湿性改变机制归因于结构分离压力。此外，NaCl和CaCl溶液在白云石和方解石样品上诱导了水湿条件，即盐析效应。因此，本研究证明了各种物质，如纳米流体、表面活性剂和盐溶液，在改变岩石润湿性和改善提高采收率条件方面的潜力。
