元素特征组合法在BZ凝析气田开发井潜山界面预警中的应用

Element characteristics combination method of buried hill interface early warning of development wells in BZ condensate gas field

渤海BZ凝析气田试验区开发井潜山界面卡取面临深层地震解释精度差、上部厚层泥岩缺少标志层、定向井及水平井井斜大、钻机提速导致岩屑细碎等作业难题。通过分析已钻井元素录井资料,应用多聚类特征选择算法对潜山及上覆地层进行敏感元素筛选,从中筛选出可进行地层对比和潜山界面深度预警的4种敏感元素Mn、S、Ca、Sr,并提出三级元素预警机制,建立区域元素特征剖面,实现了潜山上覆地层精细划分对比及界面深度预警;根据泥岩中Ca元素含量变化,建立两类潜山卡取模式类型,用于预警进入潜山钻井参数变化,实现了潜山界面深度和进入潜山钻井参数的精准预警,助力现场快速完成潜山界面的卡取,为钻井施工安全及潜山储层开发保护提供了技术保障。

Buried hill interface identification of development wells in the test area of the BZ condensate gas field is faced with some operational problems,such as poor accuracy of deep seismic interpretation,lack of marker layer in upper thick mudstone,large deviation of directional and horizontal wells,and fine fragmentation of cuttings by using high speed tools.The multi⁃clustering characteristics selection algorithm is applied to screen the sensitive elements in buried hill and its overlying strata by analyzing the element logging data of drilled wells.Four sensitive elements Mn,S,Ca and Sr are selected,and a three⁃level element early warning mechanism is put forward,and a regional element characteristic profile is established to realize the fine division and correlation of overlying strata and interface depth early warning of buried hill.According to the variation of Ca content in mudstone,two types of stuck models are established for early warning of the change of drilling parameters entering the buried hill.It realizes accurate early warning,helps the well site quickly complete the stuck of buried hill interface,and provides a solid technical guarantee for drilling construction safety and protection for buried hill reservoir.