粘土防膨剂有效期影响因素试验研究

Experimental Study on the Influencing Factors of the Validity Period of Clay Inhibitor

研究防膨剂有效期对油田开发和钻完井具有重要意义。参考聚合物驱、化学驱等有效期研究方法,确立防膨剂注入后,地层渗透率下降至初始渗透率60%作为失效临界点为有效期的方法。将渗透率、注入速度、防膨剂浓度、注入方式作为变量,设计动态驱替试验验证单一因素对有效期的影响。实验表明,注入速度不宜过慢,注入方式宜采用高浓度段塞式注入,浓度要根据油田储层的渗透率高低确定,在经济性可行前提下尽量采用相对高的浓度。

It has become an effective measure to effectively control clay swelling in water-sensitive oilfield by using clay inhibitor. It is of great significance to study its validity for oilfield development,drilling and completion.After investigate data about polymer, chemistry and so on, the paper gives a way to confirm the period of validity of clay inhibitor when formation permeability decreases to 60% of initial permeability as the failure critical point.Factors which inflect period of validity of clay inhibitor are consisteding of infusing fluid, character of reservoir and injecting technics.Comprehensive controllability and importance, permeability, injection rate, clay inhibitor concentration, injection mode are listed as experimental research factors.Designing dynamic displacement test, taking four main factors as variables and other factors as constants, completes the research on the effect of each single factor on the validity period. Experiments show that injection speed should not be too slow, injection mode should adopt high concentration slug injection, concentration should be determined according to the permeability of oil reservoir, and relatively high concentration should be adopted as far as possible under the economic feasibility.