## 2 Geological Setting  
Kuqa Foreland Basin, as the north part of Tarm Basin, is bordered by the South Tianshan Mountain to the north and linked to the Tabei Uplift and Awati Sag to the south. The Kuqa Foreland Basin is the key productive gas zone of the Tarm Basin, with an exploration area of 28 \(\times\) 10\({}^{3}\) km\({}^{2}\), 500 km from west to east, and 30-70 km from north to south (Figure 1A) [3]. The Kuqa Foreland Basin contains four tectonic units: the Northern Structural Belt, Kelasu Structural Belt, Qiulitage Structural Belt, and the Southern Structural Belt from north to south [45]. The Northern Structural Belt, located in the northmost region of the Kuqa Foreland Basin, comprises four distinct sub-structural domains: the Northern Slope Belt, the Central Anticline Belt, the Southern Slope Belt, and the Sag Belt (Figure 1B,C). The Dibei Gas Field is the main gas condensate generation zone in the northern Kuqa Foreland Basin (Figure 1B) [44; 46; 53].  
Figure 1: _Cont._  
The three stages of tectonic evolution can be divided in the Kuqa Foreland Basin: a foreland basin stage during the Triassic period, an extensional rift stage in the Jurassic and Cretaceous periods, and a rejuvenated foreland basin stage from the Early Paleogene to the present [54]. Multiple source rocks are developed in the Triassic and Jurassic strata, including the Kezilenuer (J\({}_{2}\)_k_z), Yangxia (J\({}_{1}\)_y_) and Taliqike (T\({}_{3}\)_t_) coal measures source rocks and the Huangshanjie (T\({}_{3}\)_h_) fluvial-lacustrine source rocks (Figure 2) [44,55], with a decreasing maturity from the Yangxia Sag Belt to the Yiqikelike Anticline Belt [4] (Figure 1C). The reservoirs are mainly developed in the Yangxia Formation (J\({}_{1}\)_y_) and Ahe Formation (J\({}_{1}\)_a_), with relatively good reservoir properties (porosity: 2-12%, permeability: 0.01 mD-100 mD) and are adjacent to source rocks (Figure 2). The Jurassic reservoirs are mainly dominated by fine-grained lithic arkose sandstone and siltstone deposited in braided rivers and delta environments [56]. The development of micro-fractures in each sub-structural interval strongly affected the migration of hydrocarbons and formed an effective storage space in deep gas reservoirs [57,58]. The J\({}_{2}\)_k_z_ and J\({}_{1}\)_y_ source rocks acted as excellent regional seals or overlying seals for the preservation of oil and gas accumulated in the Jurassic reservoirs [44,59]. During the late Himalayan orogen (\(\sim\)23.3 Ma), large amounts of secondary thrust faults were reactivated under the influence of intense tectonic compression in the northern Kuqa Foreland Basin [48,60,61], leading to the rapid burial of source rocks and complex in-reservoir alternation of accumulated oil and gas [44,62,63].  
Figure 1: (**A**) Location map of the Kuqa Foreland Basin, Tarim, NW China; (**B**) Structural outline map of the northern Kuqa Foreland Basin showing the distribution of trust faults, gas reservoirs and wells, the boundary of four sub\(-\)structural belts, and the position of the N\(-\)S cross\(-\)section AA\({}^{\prime}\); (**C**) N\(-\)S cross\(-\)section AA\({}^{\prime}\) of the Kuqa Foreland Basin showing the location of wells in sub\(-\)structural belts, the distribution of various thrust faults, and the key stratigraphic intervals. The stratigraphic symbols in the AA’ section are shown in Figure 2.