# Deep Learning Logging Sedimentary Microfacies via Improved U-Net
## 3 Results and Analysis  
### Dataset  
The logging data used in this paper come from the Triassic formation in the LN area of the northern Tarim Basin, which is a very important oil-gas-bearing formation [24]. It is mainly composed of clastic rocks deposited in fluvial lacustrine facies, including conglomerate, sandstone, siltstone, mudstone and their intermediate products. It has the characteristics of a positive rhythmic grain sequence combination, and is a set of inland \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Predictive Label**} \\ \cline{3-5}  & & **A** & **B** & **C** \\ \hline True & A & PAA & PAB & PAC \\ \cline{1-1} label & B & PBA & PBB & PBC \\ \cline{1-1}  & C & PCA & PCB & PCC \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Three-category confusion matrix. fluvial lake delta facies deposits. Drilling and well logging data show that these sedimentary facies can be divided into three sedimentary microfacies: submerged bifurcated channel, river channel margin and river channel bend [26]. Sedimentary microfacies, as a combination of lithofacies, have certain characteristic rules in terms of sediment lithology, grain size distribution, shale content and porosity, which are caused by hydrodynamic factors in the depositional environment. In addition, the difference in hydrodynamic conditions will cause changes in the petrophysical properties of sediments, such as electrical conductivity, natural radioactivity and acoustic wave transmission velocity. As the response of petrophysical properties around the borehole wall, the logging curve is of great significance for the fine division of lithofacies or sedimentary microfacies. The morphology of well logging curves can help to classify sedimentary microfacies. The sediments in the submerged bifurcated channel are mainly sandstone and pebble sandstone, and their spontaneous potential curves and natural gamma ray curves are characterized by low to medium microdetate or toothed bell shapes, and sometimes box shapes, or a combination of both. The sediments of the microfacies at the lateral edge of the channel are mainly fine sandstone or siltstone, with argillaceous sandstone interheods, medium to high resistivity, medium negative spontaneous potential, and obvious zigzag curves. River channel bends have high micro-facies shale content, low apparent resistivity amplitude and generally low amplitudes of natural gamma rays and spontaneous potential curves, which are flat or micro-toothed with a low amplitude [27]. Figure 9 is an example of the division of three sedimentary microfacies. In the process of identifying sedimentary microfacies using logging curves, logging curves that can reflect rock lithology, grain size, shale content and porosity are usually selected. The abnormal amplitude of (SP) and the amplitude of GR can reflect the grain size and shale content in the formation. For clastic rock reservoirs, GR and SP are the most commonly used logging curves to indicate lithology, and permeable layers can be displayed in sand-mudstone sections [28]. DEN can indirectly describe the porosity of the sedimentary body and reflect the grain size and lithological characteristics of the sedimentary body [29]. Since a sedimentary facies is a combination of lithofacies, and a lithofacies is a combination of lithological characteristics, the change curve L of lithological characteristics reflected by logging curves is an important basis for identifying sedimentary microfacies. According to the logging data, we selected SP, GR, DEN logging curves and lithology curve L as the basic data for identifying sedimentary microfacies in this area. The available dataset contains well log data from 19 wells. The four curves of each well are arranged to form a two-dimensional matrix, forming 19 original images. We took the results of the manual identification of sedimentary microfacies by geologists by observing lithological columns and characteristics of logging curves, and made them into the actual labels of the corresponding wells.