Comparison of the Three Months Ended March 31, 2021 to the Three Months Ended March 31, 2020
Oil, Natural Gas and NGL Revenues
For the three months ended March 31, 2021, our oil, natural gas and NGL revenues were $36.4 million, an increase of $10.8 million from $25.6 million for the three months ended March 31, 2020. The increase in oil, natural gas and NGL revenues was directly related to the increase in the average prices we received for oil, natural gas and NGL production for the three months ended March 31, 2021 as discussed below.
Our revenues are a function of oil, natural gas, and NGL production volumes sold and average prices received for those volumes. The production volumes were 1,234,890 Boe or 13,721 Boe/d, for the three months ended March 31, 2021, an increase of 19,328 Boe or 363 Boe/d, from 1,215,562 Boe or 13,358 Boe/d, for the three months ended March 31, 2020. The increase in production for the three months ended March 31, 2021 was primarily attributable to production associated with the Springbok Acquisition, which accounted for 180,066 Boe or 2,001 Boe/d. The increase was offset by a reduction in production on our other assets as a result of the COVID-19 outbreak and international supply and demand imbalances and, to a lesser extent, the winter storms experienced in parts of the United States in February 2021, which caused the temporary shut-in of certain properties in which we have an interest. See Business Environment — COVID-19 Pandemic and Impact on Global Demand for Oil and Natural Gas for further discussion.
Our operators received an average of $54.52 per Bbl of oil, $3.31 per Mcf of natural gas and $24.45 per Bbl of NGL for the volumes sold during the three months ended March 31, 2021 compared to $45.25 per Bbl of oil, $1.93 per Mcf of natural gas and $13.17 per Bbl of NGL for the volumes sold during the three months ended March 31, 2020. The three months ended March 31, 2021 increased 20.5% or $9.27 per Bbl of oil and 71.5% or $1.38 per Mcf of natural gas as compared to the three months ended March 31, 2020. This change is consistent with prices experienced in the market, specifically when compared to the EIA average price increases of 27.6% or $12.55 per Bbl of oil and 84.2% or $1.60 per Mcf of natural gas for the comparable periods.
Lease Bonus and Other Income
Lease bonus and other income remained flat at $0.2 million for both the three months ended March 31, 2021 and 2020.
(Loss) Gain on Commodity Derivative Instruments
Loss on commodity derivative instruments for the three months ended March 31, 2021 included $13.2 million of mark-to-market losses and $1.0 million of losses on the settlement of commodity derivative instruments compared to $9.0 million of mark-to-market gains and $1.1 million of gains on the settlement of commodity derivative instruments for the three months ended March 31, 2020. We recorded a mark-to-market loss for the three months ended March 31, 2021 as a result of the increase in strip pricing from the three months ended December 31, 2020 to the three months ended March 31, 2021. The mark-to-market gain recorded for the three months ended March 31, 2020 was due to the decrease in the price of oil and natural gas contracts relative to the fixed-price in our open derivative contracts.
Production and Ad Valorem Taxes
Production and ad valorem taxes for the three months ended March 31, 2021 were $2.4 million, an increase of $0.8 million from $1.6 million for the three months ended March 31, 2020. The increase in production and ad valorem taxes was primarily attributable to the Springbok Acquisition and the increase in the average prices we received for oil, natural gas and NGL production for the three months ended March 31, 2021.
Depreciation and Depletion Expense
Depreciation and depletion expense for the three months ended March 31, 2021 was $7.9 million, a decrease of $5.4 million from $13.3 million for the three months ended March 31, 2020. The decrease in depreciation and depletion expense was due to the impairment that was recorded during the year ended December 31, 2020, which significantly reduced our net capitalized oil and natural gas properties.