Abstract: To develop complex reservoirs more efficiently, and to accelerate the progress of drilling and completion techniques in the Shengli Oilfield during the 12th Five-Year Plan Period,development requirements and drilling difficulties encountered in some difficult-to-produce reservoirs were reviewed in detail. Such reservoirs include shallow marine beach deposits, low permeability and extra heavy oil reservoirs. During the course, research was performed related to the drilling of complex wells, the development of measuring-while-drilling instruments, innovative rock-breaking tools, expandable pipes, drilling fluids and other techniques and tools. Onsite application results showed technical progress in highly-deviated wells, high-density cluster wells and while other aspects effectively enhanced the overall development performances of shallow-marine hydrocarbon reservoirs. At the same time, relevant costs were reduced with development efficiencies enhanced dramatically. Hydraulic jet radial horizontal wells, near-bit geosteering drilling and magnetic guidance drilling technique enriched the fine development of complex reservoirs such as those with extra heavy oil and those in complex blocks. Automated strap-down vertical drilling, torsional impact drilling tools, high-performance drilling fluids and expandable tubular plugging techniques effectively removed the technical problems of slow ROPs and more complicated situations in deep wells. In consideration of existing drilling and completion techniques in the Shengli Oilfield, development proposals for the 13th Five-Year Plan Period were highlighted with regard to automatic operation of drilling facilities, top-end monitoring and control while-drilling, digitalization and environment-friendly drilling techniques. Application of these techniques might further promote fast development of drilling and completion technologies in the Shengli Oilfield, and to develop complex reservoirs more efficiently and to tap potential remaining recoverable oil/gas reserves.