Hydraulic fracture is a well-developed and widely used technology across petroleum upstream operations. The process involves the high-pressure injection of ‘fracking fluid’, mainly water containing proppants and thickening agents, into wells to form underground artificial fractures. The fracking fluid extends forward and supports those fractures to create diversion channels which lead to increased production. Therefore, it is of great significance to improve the permeability of the fractured formation, which leads to increased oil and gas production, and improved efficiency of oil and gas wells. Due to the importance of conductivity in such operations, the quality of s proppants are a critical factor affecting the fracturing efficiency and stimulation. For improvement of proppant, high strength often comes at the cost of increased density. During fracturing stimulation, it demands a higher flow rate, viscosities, and pumping pressure. It also results in the consumption of a significant amount of power, fresh water and produces more greenhouse gas and chemical pollution in the formation and the well site.
This study investigated the production of an Ultra-Lightweight Proppant made by Graphene Aerogel (GA) and Epoxy Resin (ER) composite. GA with graphene as the basic structural unit is a low-density solid material with a high specific surface area, abundant nanoporous structure and good mechanical properties. Cured ER has the characteristics of small deformation and shrinkage, good dimensional stability, and high hardness. ER is one of the commonly used substrates in resin matrix composites.
The main research contents of this study are as follows:
1. Using graphene oxide solution as a precursor to prepare graphene hydrogels, then make graphene aerogels through supercritical drying or freeze-drying. The graphene aerogel was placed in ER, followed by immersion in a vacuum environment, and then thermally cured to obtain a graphene aerogel-epoxy composite. The prepared GA has a network microstructure; the ER combined with the aerogel, and the composite material have good mechanical properties, strength is about 50 MPa. Specific gravity is 1.2, 55% lighter than silica sand and 63% lighter than ceramic proppant.
2. Spherical GA were produced using a droplet freezing method, which was combined with ER to create spherical fracturing proppants. The graphene aerogel-epoxy resin composite compressive strength is about 30 MPa, which is significantly higher than silica sand. The sphericity is about 0.9, better than silica sand (0.6-0.8) and same as ceramic proppant (0.9). its crushing rate is better than intermediate-density ceramic at 50, 70, and 100 MPa. The conductivity test showed that this new proppant was 30% and 50% higher than traditional silica sand and ceramic.
3. In the Field study, collecting core sampling and fluid analysis results to evaluate the porosity formation, permeability, fluid density and oil viscosity. Analyzation of the fracturing treatment data for the pressure testing data within the current field. Using the test results of the graphene aerogel spherical epoxy proppant (GAS-EP) modelling conducted for fracturing half-length and fracturing width, the result showing the new proppant can improve the fracturing length by 35% and increase oil Estimated ultimate recovery (EUR) volume about 10K bbl.
4. Based on field data and modelling results, horizontal well decline curve were generated for each scenario, using economic indicators, such as NPV value, payback time and others estimated that the break-even price of GAS-EP will be $2800/t.
5. Discuss the environmental benefits, using GAS-EP could reduce chemical additives by 4600L, reduce freshwater consumption 190m³ and reduce CO₂ emission 1.3 tons for a single fracturing stimulation.
The study resulted in the production of a novel proppant with improved properties compared to the conventional materials. The results of this study provide a better understanding of the novel proppant properties and concluded that the novel proppant could safely use in the petroleum industry for enhance hydrocarbon recovery and significant environmental and economic benefits.
| Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/bxf4-4f54 |
| Date | January 2023 |
| Creators | Ding, Jiasheng |
| Source Sets | Columbia University |
| Language | English |
| Detected Language | English |
| Type | Theses |
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