胜北构造泥页岩水敏性与井眼稳定性关系

为探求吐哈油田胜北构造粘土矿物水敏特性与井眼稳定性的关系，详细分析了Ｅｎｓｕｌｉｎ膨胀仪和ＣＳＴ分散仪使用中存在的问题，解释了泥页岩理化性能评价中各参数的物理意义，提出Ｍ５０００和Ｙ１５—Ｂ评价泥页岩的潜在膨胀和分散能力，以台参２井为例测试了泥页岩吸水膨胀和吸水分散的特性，研究表明在３０００ｍ以上，由于伊蒙混层矿物含量较高，地层压实弱，吸水膨胀和分散能力较大，水敏性强．在３０００～４０００ｍ井段，地层吸水快，但膨胀慢、分散慢，且膨胀和分散潜在能力较小，属中弱膨胀、中弱分散地层．在４０００ｍ以下，地层压实性好，膨胀弱分散慢，属弱膨胀的分散地层．总体上说，用泥页岩分类标准来评价，均属低膨胀低分散地层．井眼的不稳定主要不是由于粘土矿物的膨胀和分散而是过长时间的钻井液浸泡引起的地层周期性应力剥蚀所为．

The Relationship Between the Water Sensitivity of the Mud Shale and Hole Stabilization in Shengbei Structure

For searching for the relationship between water sensitivity of the clay in Shengbei structure of Tuha Oil Field and hole stabilization, the authors analyze the problems in the use of Ensulin dilatometer and CST dispersion instrument, and interpret the physical significance of each parameter used for evaluating the physical-chemical property of mud shale. It is suggested that the swelling and dispersing capacity of mud shale should be evaluated by M5000 and Y15-B. The evaluated results of Taican-2 well show that, above 3000m, the water absorption swelling and dispersing capacity of the mud shale is greater because of higher content of illite/smectite mixed layer; in 30004000m, formation absorbs water quickly, swells and disperses slowly, and its potential capacity in swelling and dispersion is inferior; under 4000m, swelling is weak, dispersion is slow, so the formation is classfied into weak swelling and dispersion formation. According to mud shale classification criterion, the formations all are classified low swelling and dispersion formation. In Accordance with the research results of this paper, it is held that the main cause leading to the hole unstability in Shengbei structure is the cyclic formation stress corrosion caused by long-term drilling fluid soak instead of the swelling and dispersion of the clay.