Distinguish geological work from drilling and equipment
Geological and geophysical expenditures connected with domestic oil or gas exploration or development have a specific amortization rule under section 167(h). For taxpayers outside the major integrated oil company rule, the statute generally uses 24 months and a half-year convention. The fact that the work helps decide where to drill does not automatically put it into the intangible drilling cost expensing election.
Begin with the services purchased and the location and purpose of the work. Surveying, seismic analysis, drilling services, equipment purchases, mineral rights, and ongoing production expenses can require different treatment. A vendor’s label or a general exploration budget does not establish the applicable category. Keep geological and geophysical costs separately identifiable before the annual deduction model is prepared.
Apply the half-year convention in a worked case
Assume a calendar-year taxpayer outside the major integrated company rule incurs $120,000 of qualifying domestic geological and geophysical expenditures during 2026. Assume no short tax year, special allocation, or other adjustment changes the basic statute. The half-year convention treats the expenditures as paid or incurred at the midpoint of the taxable year for this recovery rule.
Dividing $120,000 by 24 months gives $5,000 per month. The simplified schedule is $30,000 for 2026, $60,000 for 2027, and $30,000 for 2028. At an assumed 21% federal corporate rate, the 2026 deduction has a simplified tax value of $6,300, rather than $25,200 from treating the entire $120,000 as immediately deductible. The calculation excludes other deductions, limits, and state treatment.
Suppose the taxpayer abandons the associated prospect in early 2027 after receiving unfavorable results. Section 167(h) provides that retirement or abandonment does not create a separate deduction accelerating the remaining geological and geophysical expenditures; their amortization continues. On the stated assumptions, the taxpayer does not replace the remaining schedule with a $90,000 abandonment deduction in 2027. It continues the statutory recovery.
Review the taxpayer category and project changes
Major integrated oil companies are subject to a different statutory period, so confirm the taxpayer’s status rather than applying the 24-month rule to every enterprise. The domestic location requirement also matters. Costs related to foreign exploration require a separate analysis. A project can have both domestic and foreign work, making invoice allocation and service descriptions important to the final treatment.
If the business purchases data, rights, or an existing exploration business rather than directly incurring qualifying geological and geophysical expenses, determine the actual asset and tax treatment. Likewise, a later disposition of an interest may have consequences different from simply abandoning a prospect. The worked example assumes direct qualifying expenditures and a straightforward abandonment within the amortization period.
Maintain a schedule that survives an unsuccessful prospect
Keep contracts, invoices, geographic descriptions, technical reports, payment or incurrence support, taxpayer-status analysis, and project identifiers together. Record the amount entering section 167(h), the applicable period, the half-year convention, annual deductions, and remaining unrecovered amount. Reconcile the schedule to the ledger so expenses are not simultaneously deducted as drilling costs or added to another recovery base without justification.
When management closes an unsuccessful prospect, preserve its tax amortization schedule instead of deleting the project record along with the operating budget. Assign responsibility for carrying the remaining deduction into later returns. The project may cease to appear on current operating dashboards while its tax recovery continues. A closeout checklist should therefore distinguish commercial abandonment from the tax consequences of that abandonment.
Before an estimated-payment review, update the forecast for the actual statutory deduction rather than the cash spent or the book impairment. The $120,000 payment in the example consumes cash in 2026, but only $30,000 enters the simplified first-year recovery schedule. Abandonment in 2027 does not create an extra cash refund of the unamortized balance. The concrete action is to classify geological and geophysical costs, verify taxpayer status and location, and retain the continuing amortization file even when the underlying exploration decision ends.
Compare this schedule with other project costs separately so a valid deduction for one category does not become an unsupported immediate writeoff for the entire abandoned project.
Sources & further reading
Consult the original guidance and its effective dates. These references support the educational discussion; their application depends on the specific facts.