As of December 31, 2020, our assets consisted of mineral interests underlying 787,264 gross acres and 24,350 net royalty acres in the Permian Basin and Eagle Ford Shale. Diamondback is the operator of approximately 52% of this acreage. As of December 31, 2020, there were 7,167 wells producing on this acreage, of which Diamondback was the operator of 1,694 wells. Net production during the fourth quarter of 2020 was approximately 27,699 BOE/d and net production for the year ended December 31, 2020 averaged 26,551 BOE/d. For the years ended December 31, 2020, 2019 and 2018, royalty revenue generated from these mineral interests was $247.0 million, $293.8 million and $282.7 million, respectively.
The estimated proved oil and natural gas reserves of our assets, as of December 31, 2020, were 99,392 MBOE based on a reserve report prepared by Ryder Scott, our independent reserve engineers. Of these reserves, approximately 73% were classified as proved developed producing reserves. Proved undeveloped, or PUD, reserves included in this estimate were from 426 gross horizontal well locations. As of December 31, 2020, our proved reserves were approximately 58% oil, 22% natural gas liquids and 20% natural gas.