川东地区高峰场区块气体钻井后的钻井液转换工艺

气体钻井技术近年来在川东地区高峰场区块应用较为广泛，但在气体钻井之后的后续钻进中，容易因钻井液性能不匹配或钻井液转换工艺不完善造成井壁不稳定等复杂事故。为此，对气体钻井后替换钻井液获得良好效果的峰003-6井的成功经验进行了分析总结，并得出以下认识：①当遇到地层大量出水或钻遇含有塑性石膏地层，出现不利于气体钻井的因素以及工程技术要求等原因不能继续用气体进行钻井时，需要由气体钻井转换为常规水基钻井液钻井；②进行水基钻井液转换时，必须优选钻井液密度，高峰场区块替入钻井液密度参考密度值在1.17～1.25 g/cm³较为合理；③气体钻井后替换的水基钻井液，其性能还需特别考虑具有良好的抑制性能、滤失造壁性、封堵性、流变性和抗下部膏盐层污染能力；④根据空气钻井后钻井液需达到的性能，推荐使用聚磺钻井液体系；⑤峰003-6井钻井液替换时先采用聚磺钻井液加随钻堵漏剂和复合堵漏剂的桥浆作为前置液浆，以降低失水和井漏程度，替入钻井液后及时按进尺量和钻井液消耗量补足沥青类防塌剂和大小分子聚合物复配胶液。该转换工艺可为同类地区气体钻井的后续措施提供指导。

Drilling fluids transformation after gas drilling at the Gaofengchang Block in the eastern Sichuan Basin

Gas drilling technology has been widely applied at the Gaofengchang Block in the eastern Sichuan Basin in recent years.However,during the subsequent operation after gas drilling,complicated incidents such as wellbore instability may be easily caused by the improper drilling fluid property or poor drilling fluid displacement techniques.The displacement of drilling fluid system after gas drilling was so successful on the well Feng 003-6 that the operation is then analyzed and the experiences are drawn herein....