第33卷第4期 2016年7月
钻井液与完井液
DRILLINGFLUID&COMPLETIONFLUID
doi:10.3696/j.issn.1001-5620.2016.04.005
Vol.33 No.4 July2016
考虑三向应力作用的渤南泥页岩地层塌压力
刘晓兰'，于立松2
（1.胜利石油工程有限公司钻井工艺研究院，山东东营257000；2.中国石油大学（华东）石油工程学院，山东青岛266000）刘晓兰等.考虑三向应力作用的激南泥页岩地层圳压力[].钻井液与完井液，2016，33（4)：27-31.
摘要激南区块罗家地区沙三储层以泥页岩为主，泥贾厚度大、分布广，有机碳含量高，富含油气。但是该组地层微裂缝发育，岩石强度各向异性明显，加上水化作用影响，水平井钻井过程中井壁稳定间题突出，使用传统塌压力预测模型不能有效计算泥页岩储层的妍竭压力，普通考虑弱面的分析模型通常急略了中间主应力对岩石强度的影响，预测结果也不如意。在对罗家地区泥页岩矿物成分和微裂缝分布情况分析的基础上，基于弱面强度理论，综合考虑三向应力的影响，建立了更精确的塌压力预测模型。实例分析表明，对于该区域的泥页岩钻井，一味地增大钻井液密度并不能保证并壁稳定，该区块岩石碳酸盐矿物含量较多，原始强度较高，且地层孔隙度低，如果使用控压钻井，使井底压力略低于地层压力，可增加岩石强度，增大井壁稳定性，并降低钻井成本，增加钻速。
关键词泥页岩；弱面；水平井；三向应力；毋塌压力；井壁稳定
中图分类号：TE21
文献标识码：A
文章编号：1001-5620（2016)04-0027-05
DeterminationofFormationCollapsePressureofBonanShaleTakingintoAccountTri-axial Stresses
LIUXiaolan',YU Lisong
(1.ResearchInstitute ofDrillingTechnology,Shengli PetroleumEngineeringLtd.,Dongying,Shandong257000:
2.CollegeofPetroleumEngineering,ChinaUniversityofPetroleum,Qingdao,Shandong266000)
Abstract The lithology of the Shasan reservoir formations in Luojia, Block Bonan is mainly shales that are thick and widely spread The shales are rich in organic carbon and oil and gas. Borehole instability has been encountered during horizontal drilling because of the developed fractures in those formations, the anisotropy of the formations, and the hydration of the formation rocks. Conventional models prognosing the collapse pressure of the formations cannot be used to calculate the collapse pressure. Those models that only consider the weak planes have no thought for the effect of intermediate principal stress on the strengths of rocks, and the prognoses are generally not done satisfactorily. Mineral composition and fracture distribution have been examined about the shale samples taken from Luojia, and based on the weak plane strength theory, a more accurate prognosis model, which takes into account the effects of tri-axial stress, has been established for the prediction of collapse pressure. The application of the model shows that for wells penetrated the shale formations, borehole stability cannot be realized through only higher mud weight. Carbonate formations with higher original strengths and low porosity are not uncommon in this area. If managed pressure drilling (MPD) is used with bottom hole pressure slightly lower than formation pressure, the strength of the rocks can be increased, and hence the stability of the borehole wall. This, in turm, will help reduce drilling cost and increase ROP.
Key words Shale; Weak plane; Horizontal well; Tri-axial stress; Collapse pressure; Hole stabilization
渤南区块罗家地区罗井区沙三段地层发育有数百米厚的暗色泥页岩，泥页岩层理和裂缝非常发育，钻井过程中极易发生井壁塌，影响了钻井作业效
率，增加了勘探开发成本。前人针对弱面地层的失稳已经做了大量的探索研究。Aadony、Ong等[1-] 使用弱面强度理论率先讨论层理性地层对斜井井壁
基金项目：胜利石油管理局局级课题“泥页岩力学化学合井壁稳定预测技术研究”（GKB1304)。
第一作者简介：刘晓兰，高级工程师，1980年生，2008年毕业于中国石油大学（华东）油气井工程专业并获得博士学位，
现从事钻井工艺技术和天然气水合物方面研究。E-mail：151816360qq.com。万方数据