钻井液处理剂对安塞长6油层伤害的室内研究

A LABORATORY STUDY ON DAMAGE OF PRODUCING RESERVOIR CHANG 6, ANSAI OIL FIELD, CHANGQING, CAUSED BY DRILLING FLUID ADDITIVES

本文根据天然岩心室内伤害试验结果分析了安塞油田广泛使用的一些有代表性的钻井液处理剂对长6油层的伤害程度及产生伤害的原因,从保护油层的角度出发,对用于该油层的钻井液处理剂的选择提出了要求。

The experimental study is conducted on a static core-flow tester. Those drilling fluid additives commonly used in drilling practise in Ansai Oilfield, Changqing, are investigated, including both inorganic and organic. From the data of permeability damage obtained on a large amount of samples of natural core from Chang 6 reservoir, it is concluded:(1)Na_2CO_3 and NaOH can cause the reservoir damage and hence are to be used in controlled quantities. (2)NaCl, KC1 and CaCl_2 in sufficient concentrations help in reducing the reservoir damage. (3)From the organic additives tested the most harmful to Chang 6 reservoir is PHPAM because of strong adsorption and retention in the formation and poor compatibility with the formation water;KPAN and HPS are damageable in less extent;CMC and CMS-1 are the least harmful to the reservoir;dispersant FCLS is damageable and its use in drilling fluids is not necessary. The damage mechanizms are discussed