8.  Income Taxes  

Our income tax expense for the three months ended March 31, 2019 and 2018 was $0.2 million and $0.1 million, respectively.  Our effective tax rate was not meaningful for the periods presented as we continue to record a full valuation allowance on net deferred tax assets.  

During the three months ended March 31, 2019 and 2018, we did not receive any income tax refunds or make any income tax payments of significance.

As of March 31, 2019 and December 31, 2018, our valuation allowance was $127.8 million and $117.8 million, respectively, related to net federal and state deferred tax assets.  Net deferred tax assets were recorded related to net operating losses and temporary differences between the book and tax basis of assets and liabilities expected to produce tax deductions in future periods.  The realization of these assets depends on recognition of sufficient future taxable income in specific tax jurisdictions in which those temporary differences or net operating losses are deductible.  In assessing the need for a valuation allowance on our deferred tax assets, we consider whether it is more likely than not that some portion or all of them will not be realized.     

As of March 31, 2019 and December 31, 2018, we had current income taxes receivable of $54.1 million, which primarily relates to our net operating loss carryback claims for the years 2012, 2013 and 2014 that were carried back to prior years.  These carryback claims were made pursuant to IRC Section 172(f) (related to rules regarding “specified liability losses”), which permits certain platform dismantlement, well abandonment and site clearance costs to be carried back 10 years.  The refund claims require a review by the Congressional Joint Committee on Taxation which we expect to receive in 2019.

The tax years 2013 through 2018 remain open to examination by the tax jurisdictions to which we are subject.