坨-胜-永断裂带高密度深井钻井液技术

High density drilling fluid technology in deep wells

坨-胜-永断裂带储油层埋藏深、压力高,断层发育,构造较复杂,在钻井过程中容易发生与高密度钻井液相关的钻井问题。通过分析研究,确定在三开之前采用低密度聚合物铵盐体系,三开之后采用抗高温抗盐的聚合物硅氟防塌降滤失钻井液。提出了在该区块使用高密度钻井液技术的主要施工措施:禁止直接加加重材料,采用混重钻井液的逐步加重方式,同时保证加重材料有充分的水化时间;对直井,润滑剂总含量应为2％～3％,对定向井,润滑剂总含量应为3％～5％;该区块高密度钻井液用水的矿化度不能超标,氯离子含量应小于1000 mg/L,钙镁离子含量均应小于200 mg/L;处理剂应具备良好的抗高温和抗盐性能;保证四级固控设备的使用率,特别是离心机在每次下钻后调整钻井液时的使用至关重要。现场应用表明,聚合物硅钾基防塌降滤失钻井液具有滤失量低、抑制性强、抗高温、防塌和润滑性能好、携岩能力强等优点。

Engineering problems related with high density drilling fluid often occur in Tuozhuangxiang-Shenglizhen-Yonganzhen faulted zone in Shengli oilfield because of deep reservoir, high pressure, mature fault and complex structure. Based on analysis, it was determined that using low density polymer ammonium salt drilling fluid system before drilling 215. 9 mm hole and using polymer fluosilicic drilling fluid with temperature stability and salinity tolerance ability in the very hole. Main measures for high density drilling fluid technology in the block are presented. When weighting the drilling fluid, it should not add material directly into the fluid, but mix it step by step, ensure the weighting material having enough time to be hydrated; total content of lubricant should be 2% -3% in vertical well and 3%-5% in directional well; salinity of water used in high density drilling fluid must not more than the normal amount, e. g. , chloride ion content should be more than 1000 mg/L and calcium & magnesium ions would be less than 200 mg/L; all the additives must have enough heat tolerance and salt resistance; four-stage solid control equipment should be used effectively, especially centrifuge must be used during circulating mud after running the pipes. Field using shows that polymer silicon potassium base drilling fluid have such advantages as low filtrate loss, high inhibition, good temperature tolerance, good sloughing control and lubrication, and high carrying cutting capacity.