液相欠平衡钻井合理欠压值设计方法

发布时间：2018-08-11 10:04

【摘要】：液相欠平衡钻井井底欠压值的确立和控制直接决定着钻井的成败。目前钻井行业井底欠压值确立方法一般基于现场经验,误差较大,在现场应用时,其控制调节缺乏理论依据。欠压值过大,易导致井壁失稳,出现井控风险及速敏、应力敏感等储层伤害问题;欠压值过小,易导致钻井液进入储层,无法实现有效保护储层及提高机械钻速的目的。为此,利用井眼力学稳定及井控风险分析确定欠压值上限,利用储层毛细管力确立欠压值下限,建立液相欠平衡钻井合理欠压值设计新方法,并结合塔里木盆地塔北地区X井现场数据进行分析优化。结果表明,此欠压值设计新方法能够为欠平衡钻井现场设计提供理论指导,避免了单纯依靠经验值确立欠平衡钻井欠压值导致的钻井事故或储层保护效果不好等问题。
[Abstract]:The establishment and control of underpressure at bottom hole of liquid-phase underbalanced drilling directly determine the success or failure of drilling. At present, the method of establishing underpressure of bottom hole in drilling industry is generally based on field experience, and the error is large. When it is applied on site, its control regulation lacks theoretical basis. If the value of underpressure is too large, it will easily lead to instability of wellbore, well control risk and speed sensitivity, stress sensitivity and other reservoir damage problems, and too small under-pressure value will easily lead to drilling fluid entering the reservoir, which can not effectively protect the reservoir and improve the mechanical drilling speed. Therefore, the upper limit of underpressure is determined by wellbore mechanics stability and well control risk analysis, the lower limit of underpressure is established by using reservoir capillary force, and a new design method of reasonable underpressure value for liquid underbalanced drilling is established. The field data of well X in Tarim Basin are analyzed and optimized. The results show that the new method can provide theoretical guidance for the field design of underbalanced drilling and avoid the problems such as drilling accident or poor reservoir protection caused by simply relying on the experience value to establish underpressure value of underbalanced drilling.
【作者单位】：西安石油大学石油工程学院;
【基金】：国家自然科学基金项目“酸性气体侵入井筒在钻井液内赋存状态及对瞬态流动影响研究”(51604224) 陕西省自然科学基础研究计划项目“超临界CO2微小井眼径向水平井开发煤层气机理研究”(2015JQ5147) 陕西省教育厅科研计划项目“页岩储层压缩性对压裂裂缝扩展的影响规律研究”(15JK1566)
【分类号】：TE249

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