高矿化度水对钻井液性能的影响

The effect of high salinity water on drilling fluid property

钻井液用水总的矿化度大于2000mg/L并且其中Ca^(2+)、Mg^(2+)含量大于300mg/L时,钻井液性能难以控制,维护处理困难,井下极易发生复杂情况,增加钻井费用。华北油田冀中坳陷文49-2井的实践表明,若使用高矿化度水,要用Na_2CO_3预处理,其加量不得过大;用NaOH控制pH值在9—9.5范围内,以防促使地层粘土水化分散;使用好固控设备,及时处理钻井液,控制膨润土含量在60g/L左右。

The total salinity of water is added in drilling fluid over 200 mg/L when the content of Ca2+, Mg2+ over 300 mg/L . The drilling fluid property is difficult to control and to maintain. It is easy to lead downhole drilling problems and costs more. It is practice that the high salinity water is used in Wen 49-2 well in the Jizhong depression of Huabei oilfield. Not too much Na2CO3 is added in and pro-processed with the help of NaOH controlling the pH value between 9 to 9. 5,in case the shale of formation is dispersed in mud. The solid control devices should be used good in the drilling fluid dealt with in time and the content of bentonite should be controlled about 60 g/L or so.