萨南油田用JGN钻井液完井液体系

JGN drilling/completion fluid for Sanan oilfield

萨南油田东部过渡带成岩性差,胶结疏松,钻井过程中易发生坍塌.试验区开采层位为萨尔图组和葡萄花组,萨尔图组具有较强水敏性,葡萄花组具有一定速敏性.采用JGN钻井液体系钻井.该体系主处理剂为JGN、JN、FTD,它们的最佳配比为JGN∶JN∶FTD＝6∶3∶4,3种处理剂复配物加量大于0.6%时,钻井液滤失量小于7.0 mL,粘度为20～25 s,切力小于1.0 Pa,并具有良好的造壁性和降滤失能力,抗NaCl、CaCl2和岩屑的污染能力为6%、2%和7%,较好地解决了萨南过渡带钻井、固井、电测遇阻的问题.通过将JGN加量提高到0.8%,并加入0.2%防膨剂FP-1,将钻井液改造为完井液.JGN完井液体系的滤失量小于6.0mL,静态膨胀率小于3%,岩屑回收率大于75%,岩心渗透率恢复值大于70%.通过应用JGN完井液,与相邻区的井对比,试验井采液强度提高了14.5%,注水压力降低了6%,表皮系数降低了0.74,地层完善程度提高了31.3%,取得了较好的保护油层效果.

In the transition section of east Sanan oilfield, unconsolidated rock diagenetic texture often cause well bore collapse. According to such geological characteristics, the JGN drilling fluid was employed. In the fluid, the ratio of 3 agents of (JGN∶JN∶FTD) was 6∶3∶4, and when the dose was over 0.6%, the filtrate volume was 7.0 mL, the funnel viscosity was 20~25 s and the gel strength of 10 s and 10 min were both less than 1.0 Pa. Lab property evaluation showed, the fluid performed excellent wall building and filtration reducing ability, and the NaCl, CaCl 2 and clay bearing content were 6%, 2% and 7%, respectively. Additionally, based on the sensitivity analysis results of serious water-sensitive Saertu layers and velocity-sensitive Putaohua layers, JGN completion fluid was used. The fluid loss was controlled within 6.0 mL, the static swelling ratio was less than 35%, the cuttings recovery was more than 75% and the permeability recovery was more than 70%. Comparing with adjacent wells of the same block, the fluid productivity was increased by 14.5%, the water injection pressure was deceased by 6%, the skin factor was lowered by 0.74 and the formation efficiency was increased by 31.3%.