东海某区块致密砂岩钻井液侵入深度实验研究

针对东海区块在钻井作业中钻井液对储层造成严重伤害的问题，开展了东海某区块致密砂岩钻井液侵入深度实验研究，研究中采用了电阻测试法和体积法两种方法，通过测量钻井液侵入过程中岩样电阻和钻井液滤液最大侵入量，并根据电阻、侵入量与时间的关系拟合出侵入深度和时间的关系从而计算钻井液侵入深度。获得了花港组下段致密砂岩基块岩样钻井液侵入深度，电阻测试法计算的钻井液侵入深度主要分布在34~49 cm，体积法计算结果为30~56 cm，钻井液侵入储层后伤害程度为78.2%~97.9%，伤害程度均为强。实验研究为东海区块在钻井和完井作业中控制滤失，减小损害程度提供了依据。

Experimental Study on Penetration Depth of Drilling Fluid into Tight Sandstone in an Area of the East China Sea

To study the serious formation damage caused by the drilling fluid of drilling operations in the East China Sea area, an intrusion depth study of the drilling fluid into tight sandstone in an area of the East China Sea was performed. The resistance test method and the volume method were used in the study. The resistance of the core sample during the penetration of drilling mud and the maximum penetration volume of the filtrate of the drilling mud were measured. Based on the relationship between the resistance, penetration volume and the time, the relationship between the penetration depth and the time was obtained via fitting and the penetration depth of the drilling fluid was calculated. The penetration depth of the drilling fluid into a core sample of the tight sandstone matrix in the lower section of the Huagang Formation was obtained. The penetration depths of the drilling fluid calculated using resistance measurement and the volume method were 34～49 cm and 30～56 cm, respectively. The degree of formation damage after penetration of the drilling fluid was 78.2%～97.9%, and the damage degree was strong. This experimental study provides a basis for controlling the filtration loss and reducing the formation damage during drilling and completion operations in the East China Sea area.