This dataset represents the cradle-to-gate inventory of a product. The dataset encompasses both thickened oil and unthickened oil from offshore production. petroleum production in China is represented by 10% thickened oil and 90% unthickened oil in this production mix, and thus, the dataset can represent the average production mix for China. thickened oil reservoirs refer to reservoirs wherein, under reservoir conditions, the petroleum viscosity exceeds 50 mPas. These reservoirs have high petroleum viscosity, poor fluidity, and are challenging to exploit. Reservoirs with low permeability are characterized by low permeability of the oil-bearing formation, low abundance, and low production capacity per well. The net calorific value of petroleum is 43.4 MJ/kg, while the average calorific value of natural gas is 36 MJ/Sm3.