Research and Application of Drilling Fluid Leakage Prevention Technology in High Porosity and High Permeability Reservoirs in Lufeng Oilfield
The Zhujiang Formation reservoir section of Lufeng Oilfield is a high-porosity and high-permeability reservoir with well-developed sandstone micro-fractures.Drilling fluids can easily invade along the pores and micro-fractures,causing damage such as pore blockage and sand production in the reservoir section.The fracture channels are affected by positive pressure differences.Under the action of,it will gradually extend to the depth of the reservoir,causing the fracture opening to become larger and forming through-through fractures,thus causing serious leakage.During the historical operation of this block,leakage occurred in many wells,the plugging effect was poor,leakage relapsed after plugging was serious,and reservoir protection was difficult.Indoor,acid-soluble temporary plugging agents of different particle sizes are selected and reasonably graded,which effectively improves the pressure-bearing capacity of the well wall,and the plugging efficiency reaches 92.5%.At the same time,it cooperates with the UltraFLO drilling fluid system and uses VIRTUALMUD hydraulic software to accurately control the ECD.Reduce the positive pressure difference and effectively prevent the occurrence of well leakage.During the completion operation,invisible acid completion fluid was used to acidify and remove plugging of the formation,and the permeability recovery value reached more than 90%,effectively balancing the purpose of preventing leakage,plugging and protecting the reservoir in Lufeng Oilfield.
high porosity and high permeabilitysandstoneleak prevention and pluggingECD controlpermeability recovery value
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