川东北飞仙关高含硫地层油基钻井液复合除硫技术OA北大核心CSTPCD

The Feixianguan gas reservoir in northeast Sichuan is a high to ultra-high sulfur content reservoir.Based on the analyses of the geology of the Feixianguan formation and the difficulties in drilling fluid operation,a desulfurization measure is presented for field operation with oil based drilling fluids.High performance desulphurizing agents are first selected through laboratory experiment,and studies on the compounding of these agents are conducted to develop a compound desulphurizing agent.Evaluation of the performance of the compound desulphurizing agent to remove sulfur at elevated temperatures shows that the compound desulphurizing agent containing 3% YT-3+3% CLC-2 and 3% JD-2 has percent H2S prevention of 99.14% and percent H2S removal of 100% .The zinc-based desulfurizing agent in the formula reacted with H2S in the drilling fluids to produce insoluble chemical ZnS.The triazine and alcohol ether amide desulfurizing agents mainly remove H2S through fast and irreversible physical and chemical reactions.This desulfurization technology has been successfully applied on the well Po-005-X4 and the well Po-002-H5 when drilled into the high sulfur content Feixianguan formation,no H2S has been detected during drilling and during circulation after tripping for degassing,and the S2-content of the drilling fluid is zero throughout the whole drilling operation.The successful field operation fully demonstrates that the technology has a significant desulfurization performance and can meet the requirements of drilling high sulfur wells.