Abstract: Ultra-deepwater and ultra-shallow weakly consolidated reservoirs are prone to sand plugging, sealing failure and even wellbore collapse during wireline formation testing and sampling, which severely restricts the acquisition of fluid samples and the fine evaluation of reservoirs. Aiming at the problems of weak consolidation and fine particle size in the LS36-1 Block of the South China Sea, studies on core particle size and sand production mechanism were carried out, and an in-situ fluid sampling technology system with “active sand control and precise pressure control” as the core was established. The system includes: determining the critical sand production pressure difference threshold of 0.345 MPa, developing an ultra-low speed constant-flow pump with a minimum pumping rate of 0.2 mL/s to realize “sand production without plugging”; through adaptive modification of probes and key modules, precise pressure control procedures and optimization of operating parameters, the lower limit of applicable mobility is extended to 1 mD/(mPa·s). Field applications in more than 15 wells in the LS36-1 Block achieved 100% success rate in 55 operations, significantly improving the success rate of ultra-shallow sampling. The developed sand control sampling technology for weakly consolidated formations has the potential to be extended to other sand-prone reservoirs such as heavy oil reservoirs.