Carbon nanotubes (CNT) for enhanced oil production from shales

Abstract

The shale gas production has brought a revolution in US energy market and the global prospect of shale gas production is on continuous increase. The advancements in hydraulic fracturing made it possible to extract very low permeability shale gas through fracturing the shale rock. The once fractured shale rock is kept open with the induction of spherical particles known as proppants. The performance of proppants is crucial for oil & gas production. Therefore, the prospect of application of carbon nanotubes was explored in the present work for the development of proppants particles. The proppants testing was carried out with N2 Physiosrption, xrd, density measurement, treating with the 12:3 HCl:HF solution and Instron strength testing. The proppants testing results showed excellent properties for ceramics proppants but the performance of sand proppants was very poor.

The poor performance of sand proppants attracted motivation for the application of carbon nanotubes to improve the properties of sand proppants. The Chemical Vapor Deposition method was used for the growth of carbon nanotubes around the surface of sand particles. The testing of CNTs grown proppants was carried out for analysis of improvements in the properties of proppants. There ware no observable improvements in sphericity and strength of the sand with the coating of carbon nanotubes. There was decrease in density of CNTs sand particles which was considered to be an improvement. The increase in surface area with CNTs grown sand was motivation for development of multifunctional proppants to be used as vehicle for chemical delivery in the reservoir. The multifunctional prospect of the CNTs sand proppants was explored with the adsorption of phosphonates scale inhibitor on the surface of the CNTs sand particle. The results presented an increase in phosphonates loading with the increase in CNTs yield and reaction time which is considered to be and indication that the application of CNTs can provide breakthrough in the development of multi purpose proppants. So, the carbon nanotubes has potential to find applications for development of proppants.