【作者】 荆玲；

【导师】 李士斌；

【作者基本信息】 大庆石油学院 ， 油气井工程， 2008， 硕士

【摘要】 朝阳沟油田作为注水开发的低渗透油田,自1990年出现第一口套损井以来,套损井数逐年增多。针对这一问题,本文从套损点深度、类型、层位、注采比等八个方面对油田的套损状况进行了统计分析,发现套损点主要集中在油层,以变形为主,并且套损井数随着注水压力逐年升高,套损井数也在增加,注水压力下降,套损井数也相应减少。进而,准确地评价注水压力与套管损坏的关系,将对该油田今后注水开发及套管预防有着重要的意义。因此,本文应用压裂及粘滞剩磁定向、差应变分析及声发射法试验方法,确定了朝阳沟地区三向主应力的大小及方向,并以此为基础,根据岩体失稳判断准则,计算了朝阳沟油田防止地层滑移的临界注水压力。给出了考虑初始破裂压力和上覆岩层压力两个因素时该油田注水压力的计算方法,为油田合理控制注水压力,防止套管损坏提供了理论依据。此外本文对注水压力与套管损坏的关系进行了重点分析。以流固耦合理论为基础,应用有限元分析方法,综合考虑了井间的干扰,利用数值模拟有限元软件,模拟了不同渗透率条件下孔隙压力和渗流压力的分布,得到了套管Mise应力随注水压力增加而增大的变化关系。本文还结合朝阳沟油田油层上、下部位存在软弱层的地质发育特点,模拟了软弱面存在时套管变形情况,发现当油层上、下部位同时存在软弱面时套管的变形位移最大。通过对套管受力的模拟,提出了防止油层憋压,控制注水压力,及加强存在软弱面的油层部位套管强度的预防措施。更多还原

【Abstract】 As a low permeable oilfield, the number of casing failure wells increased year by year since the first casing failure well occurred in 1990 in Chaoyanggou oilfield. In order to solve this problem, this paper statistical analysis the situation of casing failure of this oilfield from eight different aspects, such as the depth, type, layer, injection production ratio and so on. It found that the depth of casing failure focused on the oil layer, the type of casing failure is deformation, and the number of casing failure increased with the increasing of injection pressure. When the injection pressure decreased, the number of casing failure is also deduced. So to evaluate accurately the relationship between injection pressure and casing failure has an important significance for the further exploitation by water flooding and preventation casing failure.Therefore, this paper determined the size and direction of three main earth stress with hydraulic fracture, viscous remanent magnetization, differential strain analysis, and acoustic emission methods. On the basis of the result and the destabilizing norm of rock, this paper calculate the critical injection pressure to prevent stratum slippage. And point out calculation method of the injection pressure in the oilfield on the considering two factors of initial burst pressure and overburden pressure. This gave a therotical basis for reasonable controlling injection pressure and effectively preventing casing failure.Besides, this paper emphasized on the research of the relationship between the injection pressure and casing failure. Based on rock and fluid coupling theory, applying finite elements analysis method and considering the interference among the wells, the paper simulated the distribution of pore pressure and seepage pressure under different permeability condition by using finite elements analysis software. it obtained the relation that the Mise stress of casing increases with the increasing of injection pressure. Intergrated with the geological characteristic that it has the upper and nether planes of weakness of oil layer, it also simulated the deformation of casing when the planes of weakness exist. It found that if both the upper and nether planes of weakness exist, the shift of casing deformation is the largest. According to the simulation of the stress on casing, the paper put forward the measures that is to control injection pressure and enhance the casing strength of the weakness place to prevent building pressure in oil layer.更多还原