# Establishing a Geological Knowledge Base for Braided River Deltas Using Google Earth
## 1 Introduction  
Braided river deltas, as important sedimentary systems widely developed along the margins of tectonically active basins, exhibit significant reservoir heterogeneity due to their complex channel bifurcation and sandbody stacking characteristics [1, 2]. This heterogeneity directly influences the distribution pattern, migration pathways, and recovery efficiency of hydrocarbons, presenting core challenges in the field of oil and gas exploration and production [3, 4, 5, 6, 7, 8, 9]. Sedimentary parameters such as wavelength (linear distance between adjacent bifurcation points), amplitude (maximum vertical distance of bifurcated channels), channel bifurcation angle, and bifurcation spacing are key elements for characterizing the morphological features and sedimentary dynamic processes of braided river deltas. Therefore, systematically investigating the distribution patterns and coupling mechanisms of these parameters holds crucial theoretical and practical significance for constructing reservoir prediction models and exploring subtle hydrocarbon reservoirs [10, 11, 12, 13, 14]. Traditional research methods primarily rely on outcrop analysis and dense well-network statistics. While outcrop analysis provides intuitive geological observation data,its limited spatial coverage makes it difficult to fully reveal the distribution of sedimentary parameters in three-dimensional space [15; 16; 17; 18]. Dense well-network statistics can obtain high-precision local data but are constrained by exploration costs and well density, hindering systematic research at regional or global scales [19; 20; 21; 22]. For braided river deltas in complex terrains or inaccessible regions, conventional methods face significant limitations in data acquisition [4; 13]. Since its launch in 2005, the Google Earth platform has become an important technical tool in geological research, leveraging its high-resolution satellite imagery, global seamless coverage, and open-access features. Early applications focused on macro-geological structure analysis and basic database construction: [PERSON] et al. [23] revealed the controlling mechanism of an X-type conjugate fault system on regional karst development through image interpretation; [PERSON] et al. [24] established a quantitative system for meandering river morphological parameters based on data from the Jialing River basin, demonstrating the global uniqueness of channel sinuosity and wavelength in this reach; [PERSON] et al. [25] constructed a quantitative model, linking channel width and point-bar length through modern river morphology measurements, providing key parameter constraints for fluvial reservoir architecture research. In sedimentology, [PERSON] et al. [13] were the first to use this platform to measure modern sedimentary data of meandering rivers, establishing a geological knowledge base including parameters such as sinuosity and wavelength, which promoted the application of remote sensing technology in quantitative sedimentary parameter research. However, current research on braided river deltas still has notable shortcomings. Methodologically, early geological knowledge base construction relied heavily on single technical approaches: dense well-network analysis focused on local sandbody geometric parameters, outcrop surveys emphasized sedimentary facies proportion statistics, satellite remote sensing was limited to surface morphological parameter extraction [13], and 3D seismic analysis was constrained by the resolution of deep reservoirs [26; 27]. Although some scholars have attempted to integrate multi-source data in recent years [28], constructing multi-level knowledge bases for sandy braided rivers through a combination of dense well networks, satellite imagery, and modern sedimentary surveys, these studies remain regional in scope and lack systematic global comparisons and dynamic mechanism analysis.