| Abstrakt: |
Unconventional natural gas reservoirs have been the focus of global natural gas exploration in recent years. As one of the unconventional natural gas reservoirs, tight sandstone gas reservoirs are widely distributed around the world. The Linxing block is located on the eastern edge of the Ordos Basin in China, and the Upper Paleozoic tight sandstone gas reservoir has rich natural gas resources. The Upper Paleozoic tight sandstone has a high degree of cementation, and its permeability distribution ranges from 0.01 to 53.07 mD, with an average value of about 0.9 mD, and its porosity distribution ranges from 0.2 to 17.68%, with an average value of about 7%. Moreover, the clay mineral content in the reservoir is high, and the core is highly sensitive to a variety of geological factors. Therefore, during the drilling process, the drilling fluid invades the formation and causes certain damage to the reservoir. As a result, the permeability of the reservoir is reduced and it is difficult to develop natural gas. In this paper, we systematically analyze the wettability characteristics and filtrate particle size of the cores of tight sandstone gas reservoirs in the Linxing block before and after sensitivity experiments. Studies have shown that the rock samples were hydrophilic before and after different sensitivity experiments. Among them, after the salt-sensitivity and soil acid-sensitivity experiments, the wetting angle of the rocks increased significantly, which was beneficial to the reduction of capillary force and the reduction of water lock. However, after the alkali sensitivity test, the wetting angle of the rock sample decreases. which will aggravate the water-lock injury. The particle size test of the filtrate in the core sensitivity test reflects that the speed sensitivity damage of the rock sample is serious, and it has salt sensitivity, alkali sensitivity, and acid sensitivity damage. [ABSTRACT FROM AUTHOR] |
