Abstract: The development of extra-low permeability gas reservoirs is difficult, and sweet spot prediction and well location design are the key to the effective development of low-permeability gas reservoirs. First, ultra-low permeability reservoir was finely characterized and the thickness of sand body was predicted using the gradient −90° phase shift of seismic data, and the types and causes of sweet spot development were identified through microscopic and logging data analysis. The gradient troughs and the attributes were identified qualitatively, and the maximum likelihood attribute and fracture density were used to identify the fracture type sweet spot development area, such as those in the H4 layer in the northern and eastern parts of the study area in horizontal direction, and H4b2 and H4b3 sublayers in the vertical direction, while in the H5 layer developed fissure type and pore type sweet spots in the southern part of the study area on the plane and in the H5a3 and H5a4 sublayers in the vertical. The distribution of pore type sweet spots is controlled by favorable sedimentary facies zones, while fracture type sweet spots mainly develop near faults and the wing areas of strong compression zones. Based on the characterization of sweet spots, two multi-bottom test wells were deployed in the H5a and the H4b layers, and achieved effective development of ultra-low permeability gas reservoirs. This study provided a reference for prediction of sweet spots in deep ultra-low permeability gas reservoirs and development plans.