二氧化碳吞吐试验中油层堵塞的原因

THE REASON OF RESERVOIR BLOCKAGE IN CO SWALLOWING-SPITTING TEST

钱思平 杜培敏 乔保林 周旭煌 张秀琼 游小淼 莫冰

Qian Siping Du Peimin Qiao Baolin Zhou Xuhuang Zhang Xiuqiong You Xiaomiao Mo Bing

二氧化碳吞吐试验中,不明泥状物、油层中的无机物和重质有机物及返排速度均有可能引起油层堵塞.中原油田文65-84井试验结果表明,不明泥状物主要来自井筒和地面,与油层堵塞无直接关系;油层中的无机物主要为碳酸钙,尽管其溶解度随二氧化碳分压的下降而下降,但温度的下降,又会使其溶解度增加,二者综合作用,碳酸钙的溶解度反而上升,所以并不会产生油层堵塞;二氧化碳的注入,使油层温度下降,重质有机物(石蜡、沥青等)析出,从而导致了油层堵塞,因此,因温度下降而析出的重质有机物才是油层堵塞的真正原因.另外,在油层较薄的情况下,大排量返排使得近井地带温度降低,有可能使重质有机物析出而使油层堵塞,因此,在实际中并非返排速度越快越好.

In the test of CO swallowing spitting made in Zhongyuan Oilfields,a new problem of reservoir blockage near wellbore area has arisen.The test result of Wen 65-84 Well in Zhongyuan Oilfields suggests that unknown mud like matter and inorgamic matter CaCO could not cause the reservoir blockage,the dialysis of heavy organic materials (paraffin,bitumen)caused by CO injection and the drop dwon of temperature is the real reason of the reservoir blockage.

10.11743/ogg20010310