Abstract:

The invasion of solids and filtrate in drilling fluids is the key reason to cause damage of high-permeability sandstone reservoir. A model for defining the invasion radius of solids and filtrate in drilling fluids under the dynamic condition was built up, according to the mass conservation equation and radial friction losses equation.In order to confirm some parameters in the model, the experiences of filtration API and dynamic fluid loss were tested in laboratory, and the results from the API filter test and dynamic fluid loss test were applied to the model. The prediction results indicated that the invasion radius of solids became great when the core permeability increased.The ideal filling temporary plugging technique could reduce the invasion radius of solids in drilling fluids.The pressure difference,filtrate viscosity,permeability and thickness of external and internal mud cakes could affect the filtration invasion radius.

Key words: reservoir damage, drilling fluid, invasion radius, prediction model, temporary plugging technique

摘要：

对于中高渗透砂岩,导致储层损害的主要因素是钻井液固相和滤液的侵入。为了确定钻井液固相和滤液侵入深度,根据质量守恒方程和径向摩阻公式,在考虑内泥饼的情况下,建立了钻井液固相和滤液动态侵入储层的深度模型。并将室内API滤失实验和动态岩心污染实验的结果应用到该模型中。预测结果表明,随着岩心渗透率的增加,钻井液固相侵入深度也逐渐增加,利用理想充填暂堵技术能减小钻井液固相的侵入深度。影响钻井液滤液侵入深度的主要因素有压差、滤液黏度、外泥饼渗透率、外泥饼厚度、内泥饼渗透率以及储层渗透率变化。

关键词: 储层损害, 钻井液, 侵入深度, 预测模型, 暂堵技术