A distribution of cash or property from a trust may or may not be a taxable event. Rather, you should look to the Form K-1 the trust distributes to its beneficiaries to determine your reportable items. If a trust is invested in an oil & gas partnership and is entitled to deduct depletion, it may elect to pass through such deductions to the beneficiaries. You should see the reportable deductions on your K-1.
Because it is impossible for me to identify and consider ALL the relevant facts, this advice is not intended or written to be used for the purpose of avoiding penalties, and cannot be used for that purpose.
Cost depletion percentage depletion are two methods of calculating the depletion deduction available under IRC Sec. 611. Pursuant to IRC Sec. 611(b)(3) (http://www.law.cornell.edu/uscode/html/uscode26/usc_sec_26_00000611----000-.html) depletion deductions for property held by a trust are apportioned between the income beneficiaries and the trust depending on the provisions of the trust. Report your allocable depletion deductions to the income beneficiaries in box 9 using code B. See page 16 of the 1041 instructions (http://www.irs.gov/pub/irs-pdf/i1041.pdf) for the manner in which you allocate the depletion deduction between income beneficiaries and the trust.
Finally, if you have not already, I recommend reviewin chapter 9 in IRS Pub 535 for details on calculating depletion (http://www.irs.gov/pub/irs-pdf/p535.pdf).