Income Tax Act — I-3.3 66.1
expense of a taxpayer means any expense incurred after May 6, 1974 that is (a) any expense incurred by the taxpayer (other than an expense incurred in drilling or completing an oil or gas well or in building a temporary access road to, or preparing a site in respect of, any such well) for the purpose of determining the existence, location, extent or quality of an accumulation of petroleum or natural gas (other than a mineral resource) in Canada, including such an expense that is (i) a geological, geophysical or geochemical expense, or (ii) an expense for environmental studies or community consultations (including studies or consultations that are undertaken to obtain a right, licence or privilege for the purpose of determining the existence, location, extent or quality of an accumulation of petroleum or natural gas), (b) any expense (other than an expense incurred in drilling or completing an oil or gas well or in building a temporary access road to, or preparing a site in respect of, any such well) incurred by the taxpayer after March, 1985 for the purpose of bringing a natural accumulation of petroleum or natural gas (other than a mineral resource) in Canada into production and incurred prior to the commencement of the production (other than the production from an oil or gas well) in reasonable commercial quantities from such accumulation, including (i) clearing, removing overburden and stripping, and (ii) sinking a shaft or constructing an adit or other underground entry, (c) any expense incurred before April, 1987 in drilling or completing an oil or gas well in Canada or in building a temporary access road to, or preparing a site in respect of, any such well, (i) incurred by the taxpayer in the year, or (ii) incurred by the taxpayer in any previous year and included by the taxpayer in computing the taxpayer’s Canadian development expense for a previous taxation year, if, within six months after the end of the year, the drilling of the well is completed and (iii) it is determined that the well is the first well capable of production in commercial quantities from an accumulation of petroleum or natural gas (other than a mineral resource) not previously known to exist, or (iv) it is reasonable to expect that the well will not come into production in commercial quantities within twelve months of its completion, (d) any expense incurred by the taxpayer after March, 1987 and in a taxation year of the taxpayer in drilling or completing an oil or gas well in Canada or in building a temporary access road to, or preparing a site in respect of, any such well if (i) the drilling or completing of the well resulted in the discovery that a natural underground reservoir contains petroleum or natural gas, where (A) before the time of the discovery, no person or partnership had discovered that the reservoir contained either petroleum or natural gas, (B) the discovery occurred at any time before six months after the end of the year, and (C) the expense is incurred (I) before 2021 (excluding an expense that is deemed by subsection 66(12.66) to have been incurred on December 31, 2020), if the expense is incurred in connection with an obligation that was committed to in writing (including a commitment to a government under the terms of a license or permit) by the taxpayer before March 22, 2017, or (II) before 2019 (excluding an expense that is deemed by subsection 66(12.66) to have been incurred on December 31, 2018), in any other case, (ii) the well is abandoned in the year or within six months after the end of the year without ever having produced otherwise than for specified purposes, (iii) the period of 24 months commencing on the day of completion of the drilling of the well ends in the year, the expense was incurred within that period and in the year and the well has not within that period produced otherwise than for specified purposes, or (iv) there has been filed with the Minister, on or before the day that is 6 months after the end of