低渗储层泥浆侵入特征与时移电阻率测井评价

东海盆地低渗油气资源丰富，但低渗储层又极其敏感，做好东海低渗储层保护是实现低渗油气资源良好开发的先决条件，为此东海盆地先后使用了两种钻井液体系，分别是反渗透水基泥浆和白油油基泥浆。为了明确两种泥浆体系对低渗储层的侵入特征，开展了（0.1～1）×10?3 μm2、（1～5）×10?3 μm2、（5～10）×10?3 μm2三种类型低渗岩心侵入实验，实验结果表明，水基泥浆和油基泥浆均对岩心存在侵入现象，随着泥浆对岩心的侵入，引起不同程度电阻率的“低侵”和“高侵”特征，利用不同泥浆的侵入特性结合时移电阻率测井可以有效分析泥浆的侵入深度、流体性质以及可动水情况，为低渗储层井筒保护、油气层选段射孔提供有效的技术支持。

Research of Mud Intrusion Characteristics in Low Permeability Reservoir and Time-lapse Resistivity Log Evaluation

The East China sea is rich in low-permeability oil and gas resources. However, low permeability reservoir is extremely sensitive, so protecting low-permeability reservoirs is the prerequisite for the development of low-permeability reservoirs. Two kinds of drilling fluid system are used respectively, which are reverse osmosis water-base mud and shortening oil-base mud. To study the intrusion characteristics of these two kinds of mud system, a low-permeability core intrusion experiment is carried out, which includes three kinds of core: （0.1～1）×10?3 μm2,（1～5）×10?3 μm2 and（5～10）×10?3 μm2. The result shows that both water-base mud and oil-base mud intrude into cores, making different degree of low-resistivity intrusion or high-resistivity intrusion characteristics. The mud intrusion depth, fluid properties and movable water condition can be analyzed effectively by using different mud intrusion characteristics combined with time-shift resistivity logging, which offers useful technical support for wellbore protection for low-permeability reservoirs and oil and gas perforating interval selection.