The exploration and development of complex oil and gas reservoirs in deep-sea and deep-earth environments are characterized by high costs and substantial risks. Consequently, geosteering while drilling technology, which integrates drilling, logging, and reservoir engineering techniques, has been increasingly adopted in practical applications. Looking-ahead detection while drilling enables real-time visualization of the undrilled formation structures ahead of the drill bit, serving as the core technology of geosteering while drilling. Among various technical approaches, acoustic phased array-based looking-ahead detection while drilling has emerged as a highly promising research direction in this field. However, traditional uniform linear arrays suffer from inherent drawbacks during beam steering at large angles of 70°~80°, including widened beamwidth, grating lobe interference, and excessive sidelobes, which make it difficult to meet the engineering requirements for high-precision geological detection. To address these technical bottlenecks, this study proposes a novel minimum redundancy linear array (MRLA) design scheme for one-dimensional acoustic phased sparse arrays, based on an improved chaotic fuzzy discrete particle swarm optimization (ICFDPSO) hybrid method. This approach innovatively integrates the design principles of MRLA with the improved ICFDPSO algorithm. Compared with traditional particle swarm optimization (PSO) algorithms, the improved algorithm not only achieves faster convergence speed and stronger global optimization capability but also achieves significant sidelobe suppression performance (with a sidelobe suppression depth of up to -19.49 dB for multi-element arrays), while effectively reducing computational complexity. By incorporating the MRLA design principles, the main lobe width of the optimized array is reduced by 40%, achieving uniform sidelobe suppression while maintaining high angular resolution characteristics. Results from simulation validation, scaled sandstone model experiments, and acoustic water tank tests demonstrate that the optimized sparse array enables precise beam steering at 70°, with comprehensive performance significantly superior to traditional uniform linear arrays—featuring narrower main lobes, lower sidelobes, and a relative error of only 6% between water tank test results and simulation data. With its compact structure and excellent performance, this array provides an efficient and practical technical solution for acoustic logging while drilling looking-ahead detection in geosteering drilling applications.