Within ultra-deep tight sandstone gas reservoirs, natural fractures indicate significant effects on reservoir performance because they can serve as storage spaces for hydrocarbons and improve the permeability. Accurate prediction of natural fractures in ultra-deep reservoirs is critical to the exploration and development of tight gas in Keshen 2 Block of Kuqa Depression. In this study, several conventional logs are selected and the R/S analysis method is introduced to predict the development and distribution of natural fractures in ultra-deep tight sandstone reservoirs. Fracture development coefficient Q is calculated based on the second derivatives of lg(R/S) function and corresponding weight of each log parameter, which matches well with linear fracture density measured from image logs. There is a positive correlation between parameter Q and fracture density, higher Q values usually indicate larger fracture density. Factors causing mismatches between calculated parameter Q and fracture density are also analyzed. Fracture dip angle, fracture filling condition, vertical resolution of logs, multiple interpretations of conventional logs, and lateral detection difference between image and conventional logs may contribute to generate those false appearances. The results in this study are expected to provide new geological references for the exploration and development of ultra-deep tight gas in Keshen 2 Block of Kuqa Depression.

在超深致密砂岩气藏中，天然裂缝显示出对油气藏性能的重大影响，因为它们可以充当碳氢化合物的储藏空间并提高渗透率。准确预测超深层储层的天然裂缝对库车De陷克深二区块致密气的勘探开发至关重要。在这项研究中，选择了几种常规测井，并引入了R / S分析方法来预测超深致密砂岩储层中天然裂缝的发育和分布。基于lg（R / S）函数的二阶导数和每个测井参数的相应权重，计算出裂缝发展系数Q，其与从图像测井测得的线性裂缝密度非常吻合。参数Q与裂缝密度之间存在正相关关系，较高的Q值通常表示较大的裂缝密度。还分析了导致计算出的参数Q和裂缝密度不匹配的因素。裂缝倾角，裂缝填充条件，测井仪的垂直分辨率，常规测井仪的多种解释以及图像和常规测井仪之间的横向检测差异可能会导致产生这些假象。研究结果有望为库车De陷克深二区块超深层致密气的勘探开发提供新的地质参考。裂缝的充填条件，测井仪的垂直分辨率，常规测井仪的多种解释以及图像和常规测井仪之间的横向探测差异可能会导致产生这些假象。研究结果有望为库车De陷克深二区块超深层致密气的勘探开发提供新的地质参考。裂缝的充填条件，测井仪的垂直分辨率，常规测井仪的多种解释以及图像和常规测井仪之间的横向探测差异可能会导致产生这些假象。研究结果有望为库车De陷克深二区块超深层致密气的勘探开发提供新的地质参考。