神泉区块Esh地层流变特性及井壁稳定分析研究

发布时间：2018-08-09 07:52

【摘要】：随着我国石油工业的不断发展,在钻井过程中钻遇复杂地层也越来越多,针对复杂地层的特性开展有针对性的技术研究,弄清其机理和相关规律,对制定相应工程技术方案,规避相关钻井风险具有重要意义。流变地层是典型的复杂地层之一,在我国的新疆、四川、中原、江汉等油气田均有较为广泛的分布。现场实践表明,由于地层沉积的非均质性,在钻遇流变地层时,往往还伴有较为突出的井壁失稳问题,这就加大了在该类地层的钻井的难度。因此,在研究地层流变特性的同时,结合井壁稳定性的分析和研究,有利于更为安全地提出解决该类复杂地层的钻井难点的对策,以达到优化完井方案,提高钻井成功率的目的,这对于我国这样一个石油消费大国是十分重要的,具有广阔的应用前景。本文以神泉区块为主要研究对象,主要开展了以下分析研究工作：1、共统计了神泉区块14口井的实钻资料,分析表明鄯善群(Esh)含有大量盐膏岩,且易蠕变缩径,因而在钻井过程中易发生卡钻等现象。同时由于钻井过程中所采用的钻井液密度等工程参数的大小不合适,在没有有效抑制蠕变的同时也造成了井壁失稳。2、进行了岩石力学特性研究,收集到神全区块鄯善群(Esh)组地层岩芯10块,按照国际岩石力学学会标准,开展了声学参数和动力学参数的测定,并进行了单轴抗压强度,三轴抗压强度试验,建立了岩石力学参数计算模型。利用测井资料计算并建立了岩石特征参数剖面。3、建立了神泉地区地层孔隙压力计算模型,结合测井资料,计算分析了该地区地层孔隙压力压力纵横向分布规律。4、针对神泉区块鄯善群组存在的盐膏层特性进行分析,在弄清地应力分布规律的基础上,建立了盐膏层流变本构方程,利用FLAC3D软件对盐膏层流变特性进行了模拟研究,确立了可描述该地区盐膏层流变行为特征的模型,计算并绘制了抑制地层流变应力的钻井液图谱。5、通过对井底围岩受力情况分析,依据库伦摩尔破坏准则,建立了地层坍塌破裂压力计算模型,通过结合测井资料,计算并绘制出地层坍塌破裂压力剖面,分析了维持井壁稳定安全钻井液密度范围,并结合所建立的抑制地层流变应力的钻井液图谱,进行了校对分析,同时根据盐膏层钻井液应具有的膨胀抑制性和饱和度对岩屑溶解率等方面特点设计了相应的钻井液体系。通过对神泉区块鄯善群组(Esh)地层流变特性及井壁稳定分析研究,形成了一套适合神泉地区鄯善群组(Esh)地层的安全、快速钻完井工艺技术,满足了安全生产的需要,减少或避免神泉地区钻完井过程中的复杂情况发生,提高了机械钻速,缩短钻井周期,扩大勘探成果,满足勘探开发的需要。
[Abstract]:With the continuous development of petroleum industry in China, more and more complex formations are drilled in the drilling process. In view of the characteristics of the complex formations, a targeted technical study is carried out to make clear its mechanism and related laws, and to formulate corresponding engineering technical schemes. It is of great significance to avoid the related drilling risk. Rheological stratigraphy is one of the typical complex strata, which is widely distributed in Xinjiang, Sichuan, Zhongyuan, Jianghan and other oil and gas fields in China. The field practice shows that due to the heterogeneity of formation deposition, there is often a relatively prominent wellbore instability problem in drilling rheological formation, which increases the difficulty of drilling in this kind of formation. Therefore, while studying the rheological characteristics of the formation, combined with the analysis and study of the wellbore stability, it is advantageous to put forward more safely the countermeasures to solve the drilling difficulties in this kind of complex formation, so as to optimize the completion scheme. The purpose of improving the success rate of drilling is very important for a large oil consuming country such as China and has a broad application prospect. Taking Shenquan block as the main research object, this paper mainly carried out the following analysis and research work: 1, and counted the actual drilling data of 14 wells in Shenquan block. The analysis shows that the Shanshan group (Esh) contains a lot of salt gypsum rock and is easy to creep and shrink diameter. Therefore, drilling is easy to occur in the drilling process, such as drilling phenomenon. At the same time, because the drilling fluid density and other engineering parameters used in the drilling process are not suitable, it can not effectively restrain the creep and at the same time cause the wellbore instability. 2. The rock mechanical properties are studied. In accordance with the International Institute of Rock Mechanics Standard, the acoustic and dynamic parameters were measured, and uniaxial compressive strength and triaxial compressive strength tests were carried out in 10 cores of the (Esh) formation in Shanshan Group, Shanshan Group, Shenquan block, according to the standards of the International Society of Rock Mechanics. The calculation model of rock mechanics parameters is established. Using logging data to calculate and establish rock characteristic parameter profile. 3, to establish the pore pressure calculation model in Shenquan area, and to combine with logging data. The vertical and horizontal distribution of pore pressure in this area is calculated and analyzed. The characteristics of salt paste in Shanshan group of Shenquan block are analyzed. The rheological constitutive equation of salt paste is established on the basis of clarifying the distribution law of in-situ stress. The rheological characteristics of salt paste layer were simulated by FLAC3D software, and a model was established to describe the rheological behavior of salt paste layer in this area. This paper calculates and draws the drilling fluid map .5which can restrain the formation rheological stress. By analyzing the stress of surrounding rock at bottom hole and according to Coulomore's failure criterion, the calculation model of formation collapse fracture pressure is established, and the well logging data are combined. The pressure profile of formation collapse fracture is calculated and drawn, and the range of drilling fluid density is analyzed to maintain the stability and safety of wellbore, and the proofreading analysis is carried out based on the drilling fluid map established to restrain formation rheological stress. At the same time, the corresponding drilling fluid system was designed according to the characteristics of the expansion inhibition and saturation to the cuttings dissolution rate of the salt gypsum drilling fluid. By analyzing the rheological characteristics and wellbore stability of (Esh) formation in Shanshan group of Shenquan block, a set of safe and rapid drilling and completion technology for (Esh) formation in Shanshan group of Shenquan area has been formed, which meets the needs of safe production. In order to reduce or avoid the complex situation during drilling and completion in Shenquan area, the mechanical drilling speed is increased, the drilling period is shortened, the exploration results are expanded, and the needs of exploration and development are met.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE21

【参考文献】