基于ABAQUS的温度对钻井液漏失影响规律

Study on Influence of Temperature on Loss of Drilling Fluid Based on ABAQUS

深层油气储层高温、高压、高应力特点给钻井工程带来极大挑战,其中钻井液漏失是常见的钻井复杂工况之一,严重制约其勘探开发进度。为研究在深层钻井过程中温度对钻井液漏失的影响规律,以ABAQUS软件平台为基础,建立了考虑钻井液动态循环的热-流-固全耦合漏失有限元模型,分析了不同钻井液温度条件下的井周应力分布、地层温度场变化、漏失裂缝延伸规律和钻井液漏失规律。研究结果表明:当钻井液温度低于地层温度时,会产生“冷却”效应,导致地层遇冷收缩,井周应力降低;低温循环会降低漏失排量阈值,且相同排量下,低温循环漏失发生得更早。然而,低温钻井液对于地层温度场的影响仅存在于近井区域。短期内,诱导裂缝宽度和长度依然由钻井液排量主导,仅在近井区域的裂缝宽度上表现出了“冷却”效应的影响。建立的热-流-固全耦合模型可以描述动态钻井过程中温度对钻井液漏失规律的影响,可为高温地层钻井设计和现场施工提供研究方法和参考数据。

The characteristics of high temperature,high pressure and high stress in deep oil and gas reservoirs bring great challenges to drilling engineering,and the loss of drilling fluid is one of the most common drilling complications,which seriously restricts the exploration and development progress.To study the influence of temperature on the loss of drilling fluid during deep drilling,a finite element model of thermo-hydro-mechanical fully coupled loss considering dynamic circulation of drilling fluid was established based on the ABAQUS software platform,and the stress distribution around the wellbore,changes in formation temperature field,propagation of leakage fractures,and loss of drilling fluid under different drilling fluid temperature conditions were analyzed.The study results show that when the temperature of the drilling fluid is lower than the formation temperature,a“cooling”effect occurs,leading to formation shrinkage and a decrease in stress around the wellbore;low temperature circulation reduces the leakage displacement threshold,and at the same displacement,low temperature circulation loss occurs earlier;however,the impact of low temperature drilling fluid on the formation temperature field only exists in the area near the wellbore;in a short period,the width and length of induced fractures are still dominated by the drilling fluid displacement,and the“cooling”effect is only shown on the fracture width near the wellbore.The established thermo-hydro-mechanical fully coupled model can describe the influence of temperature on the loss of drilling fluid during dynamic drilling process,and thus provide research methods and reference data for drilling design and field construction of high temperature formations.