井筒内气体扩散侵入定量计算模型

发布时间：2018-03-14 23:15

本文选题：气侵　切入点：扩散　出处：《石油学报》2017年09期 　论文类型：期刊论文

【摘要】：油基钻井液中更易发生气体扩散侵入,伴随油基钻井液使用的增多,有必要研究气体扩散侵入的机理并建立气体扩散侵入定量计算模型。将气体扩散侵入通道划分为气体与滤液界面、滤液滞留区、内滤饼区、外滤饼区、外滤饼区内壁与钻井液界面5个部分,在分析气体扩散侵入机理的基础上,推导了井筒内气体扩散侵入控制方程及解析解。基于解析解,给出了气体扩散侵入参量(循环工况气体侵入速率、循环工况井筒内气体总量、静止工况气体最大浓度、静止工况井筒内气体总量)的定量计算公式。结合算例分析,得到了储层长度、储层孔隙度、钻井液滤失对气体扩散侵入的影响规律。除了静止工况最大气体浓度外,气体扩散侵入参量与储层长度成线性关系。储层孔隙度的增加会促进气体的扩散侵入,但这种促进作用非常弱,低孔隙度储层和高孔隙度储层的扩散侵入参量没有数量级的差别。钻井液滤失对气体的扩散侵入具有非常明显的抑制作用,无滤失时的气体扩散侵入参量显著大于滤失时的情况。
[Abstract]:Gas diffusion is more likely to occur in oil-based drilling fluid, and the use of oil-based drilling fluid is increasing. It is necessary to study the mechanism of gas diffusion invasion and establish a quantitative calculation model of gas diffusion invasion. The gas diffusion invasion channel is divided into gas and filtrate interface, filtrate retention zone, inner filter cake area and outer filter cake area. On the basis of analyzing the mechanism of gas diffusion invasion, the control equation and analytical solution of gas diffusion invasion in wellbore are derived based on the five parts of the interface between the inner wall of outer filter cake area and drilling fluid. The quantitative calculation formulas of gas diffusion invasion parameters (gas invasion rate in circulating condition, total gas content in wellbore under circulating condition, maximum concentration of gas in static condition, total gas in wellbore under static condition) are given. The effects of reservoir length, reservoir porosity and drilling fluid filtration on gas diffusion invasion are obtained. The gas diffusion invasion parameter is linearly related to the reservoir length. The increase of reservoir porosity will promote the gas diffusion invasion, but this effect is very weak. The diffusion invasion parameters of low porosity reservoir and high porosity reservoir have no order of magnitude difference. The invasion parameters of gas diffusion without filtration are significantly larger than those without filtration.
【作者单位】：中国石油大学石油工程学院;中海油研究总院;
【基金】：国家重点基础研究发展计划(973)项目(2015CB251200) 国家重大科技专项(2016ZX05020-006-006) 国家重点研发计划(2016YFC0303303) 教育部创新团队项目(IRT_14R58)资助
【分类号】：TE254

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