中原油田井壁不稳定地层分类

Formation classification with unstable wellbore for Zhongyuan oil field

提出适合中原油田实际情况的地层分类法,阐述各类地层的岩性特征及井下易出现的各种复杂情况,以及钻各类地层应采取的各种泥浆技术措施,即钻Ⅰ类地层使用适当密度,较高粘切力的聚合物膨润土浆;钻Ⅱ类地层使用强包被的低固相不分散泥浆;钻Ⅲ—1亚类地层使用KCl聚磺泥浆;钻Ⅲ—2亚类泥浆使用抗高温聚磺泥浆;钻Ⅳ类地层使用油包水乳化泥浆和饱和盐水聚合物泥浆。

Based on the special points of Zhongyuan oil field , the formation with unstable wellbore is divided into four genera and eight subgenera . They are :Ⅰ : Unconsolidated glutenite and drift sand formation ;Ⅱ : Clay swelling formation , including three subgenera ;Ⅲ : Fragile formation with bedding and fracture development , including two subgenera;Ⅳ : Complex formation of salt gypsum and mudstone , including two subgenera. The corresponding drilling fluid technical measures for four genera of formation are given respectively .