聚磺钾盐钻井液的现场应用

东濮凹陷兰聊断层下降盘毛岗构造、庆63断缝带等区块，从沙一下下部到沙二段有大段地层含有蒙脱石及较多的伊利石和伊蒙混层；沙三段为含伊利石的硬脆页岩，滤液易沿着层理面的微裂缝渗入，引起剥蚀垮塌。在这些区块的长期钻井实践中都依靠有机处理剂来稳定井壁，经常发生井壁掉块坍塌．导致井下复杂。聚磺钾盐体系具有比较经济、易于维护、防塌效果好的特点，尤其对储集层段有很好的防塌作用，因此配制出了适合深部地层易垮塌特点的保护油气层的聚磺钾盐钻井液体系。实际应用效果表明，该体系有效抑制了下部井眼的剥落垮塌，掉块很少，钻井顺利，提高了钻进速度和井身质量，平均井径扩大率约为8．3％，并保证了较高的渗透率恢复值。

Field application of the polysulfonated potassium drilling fluid

In some blocks of the Dongpu sag in Zhongyuan Oilfield, montmorlllonite and illite layers and in-terlayer exist in the formation sections of Sha-1 and Sha-2, and the Sha-3 section is consisted of hard and fragile shale, the formation filtrate can invade along the micro-fractures of the stratification, thus causes sloughing and collapsing. In the long time drilling practices in these blocks, organic mud additives have been used for wellbore stability, yet hole sloughing and collapsing frequently take place and cause lots of downhole troubles. The polysulfonated potassium system has such advantages as low cost, easy maintenance, and good sloughing control, and is especially effective for sloughing control in the reservoir, thus the polysulfonated drilling fluid system is formulated for reservoir protection in the deep formation. Field applications show that the system is very effective for the wellbore stability in the bottom hole, the penetration rate and borehole quality are improved greatly, with an average hole enlargement of 8. 3%, and a higher permeability recovery is also obtained.