If you purchased a Rig or Equipment , The Section 179 Deduction allows business owners to write off the entire amount of equipment that is purchased or financed. 
How does Section 179 Work?
This deduction is good on new and used equipment with a limit of $510,000 To take the deduction for tax year 2017, the equipment must be financed/purchased and put into service between January 1, 2017 and the end of the day on December 31, 2017. The equipment and mobile rigs must be used for business purposes more than 50% of the time 
to qualify for the Section 179 Deduction. The maximum spent on new and used equipment is 2,030,000 to help incentivize small business owners, as anyone over that spending limit is not eligible for the deduction. However, if you do reach the spending cap you can qualify for the 50% Bonus Depreciation on new equipment only.
Who is Eligible ?
Any business owner who spent less than $2,030,000.00 mobile rigs and equipment for their business and is used more than 50% of the time.
For more information visit:
https://www.section179.org/section_179_deduction.html