克深区块裂缝性储层承压封堵技术研究

发布时间：2018-01-15 14:04

本文关键词：克深区块裂缝性储层承压封堵技术研究　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：克深区块裂缝性储层裂缝发育,地层承压能力不高,钻井液密度窗口很窄。在钻井过程中容易发生漏失、溢流等井下复杂。本文主要研究如何提高工区裂缝性储层地层承压能力。通过克深区块地质背景及地层岩性分布,以成像测井技术为基础,明确白垩系巴什基奇克组致密砂岩为典型的天然性裂缝性储层,裂缝大多为大倾角半填充裂缝；从克深区块已完钻井裂缝统计发现,工区内天然性裂缝宽度在2mmm以内；在井筒压力增大的情况下,裂缝宽度和形态会有所变化；通过地层倾角测井数据分析得到克深区块的最大主应力的方向大约为南北向,最小主应力为东西向；根据克深区块内已完钻井储层漏失概况,发现储层压力窗口很窄,对钻井液密度很敏感,漏失较频繁；通过两种承压封堵方法对比,该工区裂缝性储层更适合套管内全裸眼段封堵。漏失原因分为天然性漏失和人为性漏失；而根据漏失量大小可将漏失分为微漏、小漏、中漏、大漏、严重漏失等；根据漏失特征可将漏失分为天然性漏失、压裂性漏失、扩展性漏失；而不同漏失的机理和成像测井图像都有明显的差异,可以较好的区分。不同研究人员提出了很多应力关系与裂缝漏速的模型；发现裂缝宽度与漏速之间关系紧密,地层承压堵漏过程中,以0.15mmm和0.4mmm为界,防漏主要是针对0.15mmm以上裂缝宽度,而堵漏需研究0.4mmm以上宽度的裂缝。最后以单一理想裂缝为对象,得到裂缝宽度与漏失量的关系。提出各种封堵材料在承压封堵过程中的封堵机制。分析了采用封堵材料复合封堵,使地层承压封堵能力大大提高。通过裂缝表面单颗粒架桥、裂缝表面双颗粒架桥、裂缝内双颗粒架桥三种情况的力学分析,得出封堵颗粒选择范围。通过室内承压封堵试验,统计刚性封堵材料(核桃壳)、弹性封堵材料(SQD-98)、纤维封堵材料(锯末)的各种复合配方在1～5mm裂缝中的漏失量大小,最终得到6%核桃壳(30%中+70%细)+5%SQD-98+3%以上锯末对于1～5mm裂缝综合承压封堵效果最好。最后分析克深2-2-5井裂缝性储层承压封堵技术应用实例,结果使储层的承压封堵能力达到4.75MPa。
[Abstract]:The fractured reservoirs in Keshan block have developed fractures, low bearing capacity of formation, narrow density window of drilling fluid, and are prone to leakage during drilling. Overflow is complicated in downhole. This paper mainly studies how to improve the bearing capacity of fractured reservoir in working area. Based on the geological background and lithologic distribution of Kesheng block, the tight sandstone of the Cretaceous Bashiqike formation is defined as a typical natural fractured reservoir on the basis of imaging logging technology. The fractures are mostly large dip angle and half filled fractures; From the statistics of borehole fractures in Kesheng block, it is found that the width of natural fractures in the working area is less than 2mmm; With the increase of wellbore pressure, the width and shape of fracture will change. The direction of the maximum principal stress of Kesheng block is about north-south direction and the minimum principal stress is east-west direction through the analysis of formation dip logging data. According to the general situation of reservoir leakage in Kesheng block, it is found that the reservoir pressure window is very narrow, sensitive to drilling fluid density and frequent leakage. Through comparison of two pressure plugging methods, the fractured reservoir in this area is more suitable for plugging open hole in casing. The causes of leakage are natural leakage and artificial leakage. According to the amount of leakage, the leakage can be divided into micro leakage, small leakage, medium leakage, large leakage, serious leakage and so on. According to the leakage characteristics, the leakage can be divided into natural leakage, fracturing leakage and extended leakage. However, different leakage mechanisms and imaging logging images are obviously different, which can be well distinguished. Many models of stress relation and crack leakage velocity have been proposed by different researchers. It is found that the relationship between fracture width and leakage velocity is close. In the process of formation pressure plugging, the boundary is 0.15 mm and 0.4 mm, and the leakage prevention is mainly aimed at the width of fracture above 0.15 mm. Finally, the relationship between the width of cracks and the amount of leakage is obtained by taking a single ideal crack as an object. The plugging mechanism of various plugging materials in the process of pressure plugging is put forward. The combined plugging with plugging material is analyzed, which greatly improves the plugging ability of strata. The selection range of sealing particles is obtained by mechanical analysis of three kinds of cases: double particle bridge on crack surface and double grain bridge in crack. The rigid sealing materials (walnut shell, elastic plugging material SQD-98) were calculated by indoor pressure plugging test. The leakage of fiber plugging material (sawdust) in 1 ~ 5 mm crack. Finally, 6% walnut shell 30% of 70% fine) 5 SQD-98 3% sawdust has the best effect on the combined pressure sealing of 1mm and 5mm cracks. Finally, the application example of fractured reservoir pressure plugging technology in Kesheng 2-2-5 well is analyzed. The result shows that the pressure plugging ability of the reservoir can reach 4.75 MPA.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE28

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