长水平段钻井泥岩井壁坍塌周期分析

发布时间：2018-01-07 08:29

本文关键词：长水平段钻井泥岩井壁坍塌周期分析　出处：《科学技术与工程》2017年03期 　论文类型：期刊论文

【摘要】：泥页岩地层井壁失稳是国内外各油气田钻井过程中普遍存在且至今未能完全解决的世界性难题;但在致密泥岩长水平段钻进时,井壁失稳问题更加突出。考虑化学势差、水力压差和岩石骨架变形的耦合作用,同时考虑泥岩吸水引起的强度弱化,提出了泥岩流-固-化多场耦合坍塌周期分析模型。利用该模型,定量分析了泥岩渗透率、吸水扩散吸附系数、钻井液活度和膜效率对地层孔隙压力、地层强度以及坍塌周期的影响规律。结果表明:1泥岩渗透率越小,阻碍水力压力传递的能力越强,地层孔隙压力增长越慢,井眼坍塌周期越长;2钻井液化学作用对井周压力传递和坍塌周期影响显著,当钻井液活度高于地层活度时,井眼附近孔隙压力显著增大,井眼坍塌周期缩短;膜效率越大,则地层孔隙压力和井眼坍塌周期变化幅度越大;3泥岩强度弱化是影响坍塌周期变化的重要因素。随着吸水扩散系数增大,近井地层泥岩强度迅速降低,井眼坍塌周期显著缩短;4研究区域沿最小水平地应力方向水平钻进时,井眼坍塌周期最长,随着与水平最小地应力夹角的不断增大,井眼坍塌周期不断缩短,沿最大水平地应力方向时,井眼坍塌周期最短。
[Abstract]:The wellbore instability in shale formation is a worldwide problem that exists widely in the drilling process of various oil and gas fields at home and abroad and has not been completely solved up to now. However, in the long horizontal section of tight mudstone drilling, the problem of wellbore instability is more prominent, considering the coupling of chemical potential difference, hydraulic pressure difference and rock skeleton deformation, and considering the strength weakening caused by mudstone water absorption. The model of mudstone fluid-solid-chemical coupling collapse cycle is proposed, and the permeability of mudstone, the absorption coefficient of water absorption, the activity of drilling fluid and the membrane efficiency to the pore pressure of formation are quantitatively analyzed by using this model. The results show that the smaller the permeability of 1 mudstone, the stronger the resistance to hydraulic pressure transfer, the slower the growth of formation pore pressure and the longer the hole collapse period. (2) the effect of drilling fluid chemistry on the borehole pressure transfer and collapse cycle is significant. When the drilling fluid activity is higher than the formation activity, the pore pressure near the borehole increases significantly and the hole collapse cycle shortens. The larger the membrane efficiency, the greater the variation of formation pore pressure and hole collapse cycle. (3) the weakening of mudstone strength is an important factor affecting the variation of collapse cycle. With the increase of water absorption and diffusion coefficient, the strength of mudstone in near-well formation decreases rapidly, and the hole collapse period is shortened significantly. 4When horizontal drilling along the direction of minimum horizontal ground stress in the study area, the hole collapse period is the longest. With the increasing of angle between horizontal minimum ground stress and horizontal stress, the hole collapse period is shortened. The hole collapse period is the shortest in the direction of maximum horizontal stress.
【作者单位】：中国石油大学石油工程学院;大港油田滩海开发公司;川庆钻探工程有限公司工程技术研究院;
【分类号】：TE21
【正文快照】： 川庆钻探工程有限公司工程技术研究院3,西安710021)引用格式:袁华玉,程远方,王伟,等.长水平段钻井泥岩井壁坍塌周期分析[J].科学技术与工程,2017,17(3):183—189Yuan Huayu,Cheng Yuanfang,Wang Wei,et al.Analysis ontime-dependent wellbore collapse for long horizontal w

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