In view of the problems such as shallow depth in the reservoir, serious sand production, large perforation thickness and long span in M Oilfield of South Sudan, the long interval sand control completion technology has been studied and put into practice. In this paper, through the optimization of gravel packing sand control technology, the development of high viscosity and easy degradation sand carrier fluid, and the design of long interval easy handling sand control string, forming the long interval sand control completion technology. The technology forms a high-strength and high-permeability sand barrier by using wire-wrapped screen and ceramsite, and by optimizing the particle size combination and operation parameters, the sand retention accuracy is increased from 0.08 mm to 0.05 mm, and the sand barrier range is extended from inside the wellbore to near the well zone. The high viscosity and easy degradation sand carrier fluid system suitable for long sand producing interval is developed to improve the sand carrying capacity, enhance the anti-swelling and flow-back performance. The design of supporting sand control pipe string is improved to solve the difficult problem that the separated layer sand control pipe string is not easy to be handled out in the late period. Up to now, the technology has been applied to 5 wells, the success rate of sand control operation has reached 100%, and the cumulative oil recovery is 6.2 × 104 t, with good practice effect.