塔中区块二开井段钻井复杂情况原因分析与对策研究
发布时间：2019-02-20 07:31
【摘要】：为了减少塔中区块二开钻井复杂,本文综合运用室内试验和钻完井资料,对二开钻井两大主要问题三叠系PDC钻头泥包和二叠系井壁失稳的原因进行了分析,并提出了相应的对策。主要研究内容和研究结果如下：(1)通过展开室内试验,对三叠系和二叠系地层泥岩岩心进行了粘土矿物组分、理化性能和微观结构分析。试验表明,紫红色泥岩的高粘土含量和强分散性是造成PDC钻头反复泥包的原因；褐色泥岩高粘土含量和强分散性是造成褐色泥岩水化坍塌的客观条件；灰色泥岩存在大量微孔、晶间孔、层理缝加剧了水化,使得这段粘土含量不高的井段出现井壁失稳。(2)通过纵波时差计算了密度和横波时差,并且计算了区块二叠系地层岩石力学特性参数、上覆岩层压力和地层孔隙压力、水平地应力的大小,为后续研究提供了基础数据。计算结果表明,二叠系泊松比为0.30-0.37,弹性模量为7000-35000MPa,抗拉强度为3-13MPa,粘聚力为3-30MPa,内摩擦角为20-35。；地层上覆岩层压力当量钻井液密度为2.20-2.22g/cm3,地层孔隙压力当量钻井液密度为1.05-1.10g/cm3,最大水平地应力分别为2.35-2.55 g/cm3,最小水平地应力为2.00-2.20 g/cm3左右。(3)从力学的角度评估井壁稳定,分析井周应力分布状态,建立了基于Mohr-Coulomb强度准则的地层坍塌压力和破裂压力预测模型,计算了地层坍塌压力和破裂压力剖面。研究结果表明,二叠系坍塌压力最高达到1.45 g/cm3,较高的坍塌压力和相对较低的钻井液密度之间矛盾是井壁失稳的力学原因；破裂压力在1.70-1.90 g/cm3之间。(4)对三叠系PDC钻头泥包,进行了优选排量、使用钻井液清洁剂的对策研究,对二叠系井壁失稳,进行了钻井液密度设计和钻井液抑制剂优选的对策研究。研究表明,减少泥包应加强区块清洁剂使用管理,钻井液排量在21.59cm井眼中应达到33L/s,在24.13cm井眼中达到42 L/s；二叠系井段钻井液设计密度为1.50 g/cm3,最优抑制剂组合为3%KCL+0.4%KPAM+2%MMH。
[Abstract]:In order to reduce the complexity of second hole drilling in Tazhong block, this paper makes use of laboratory test and drilling and completion data synthetically, and analyzes the reasons for the mud-cladding of Triassic PDC bit and the instability of Permian wellbore. The corresponding countermeasures are put forward. The main contents and results are as follows: (1) the clay mineral composition, physical and chemical properties and microstructure of mudstone cores of Triassic and Permian strata were analyzed by laboratory tests. The test results show that the high clay content and strong dispersion of purple mudstone are the causes of repeated mudding of PDC bit, the high clay content and strong dispersion of brown mudstone are the objective conditions for the hydration collapse of brown mudstone. There are a large number of micropores in grey mudstone, intergranular pores and stratified fractures, which make the section with low clay content appear sidewall instability. (2) density and S-wave time difference are calculated by P-wave time difference. The parameters of mechanical properties of Permian strata, the pressure of overlying strata and pore pressure, the magnitude of horizontal in-situ stress are calculated, which provides the basic data for further study. The calculated results show that the Permian Poisson's ratio is 0.30-0.37, the elastic modulus is 7000-35000MPa, the tensile strength is 3-13MPa, the cohesion is 3-30MPa, and the internal friction angle is 20-35. The density of equivalent drilling fluid is 2.20-2.22 g / cm ~ 3, the density of formation pore pressure equivalent drilling fluid is 1.05-1.10 g / cm ~ 3, and the maximum horizontal stress is 2.35-2.55 g / cm ~ 3, respectively. The minimum horizontal stress is about 2.00-2.20 g/cm3. (3) from the viewpoint of mechanics, the stability of borehole wall is evaluated, the stress distribution around the well is analyzed, and the prediction model of formation collapse pressure and fracture pressure based on Mohr-Coulomb strength criterion is established. The formation collapse pressure and fracture pressure profile are calculated. The results show that the maximum collapse pressure of Permian is 1.45 g / cm ~ 3, and the contradiction between high collapse pressure and relatively low drilling fluid density is the mechanical reason of shaft wall instability. The fracture pressure is between 1.70 and 1.90 g/cm3. (4) the mud of Triassic PDC bit is selected and discharged optimally, the countermeasure of using drilling fluid cleaner is studied, and the stability of Permian wellbore is studied. Drilling fluid density design and optimal selection of drilling fluid inhibitors were studied. The results show that the use management of cleaning agent in block should be strengthened to reduce mud ladle, and drilling fluid discharge should reach 33L / s in 21.59cm well and 42 L / s in 24.13cm well. The design density of Permian drilling fluid is 1.50 g / cm ~ 3, and the optimal inhibitor combination is 3%KCL 0.4%KPAM _ 2.
【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】：TE28
本文编号：2426944
[Abstract]:In order to reduce the complexity of second hole drilling in Tazhong block, this paper makes use of laboratory test and drilling and completion data synthetically, and analyzes the reasons for the mud-cladding of Triassic PDC bit and the instability of Permian wellbore. The corresponding countermeasures are put forward. The main contents and results are as follows: (1) the clay mineral composition, physical and chemical properties and microstructure of mudstone cores of Triassic and Permian strata were analyzed by laboratory tests. The test results show that the high clay content and strong dispersion of purple mudstone are the causes of repeated mudding of PDC bit, the high clay content and strong dispersion of brown mudstone are the objective conditions for the hydration collapse of brown mudstone. There are a large number of micropores in grey mudstone, intergranular pores and stratified fractures, which make the section with low clay content appear sidewall instability. (2) density and S-wave time difference are calculated by P-wave time difference. The parameters of mechanical properties of Permian strata, the pressure of overlying strata and pore pressure, the magnitude of horizontal in-situ stress are calculated, which provides the basic data for further study. The calculated results show that the Permian Poisson's ratio is 0.30-0.37, the elastic modulus is 7000-35000MPa, the tensile strength is 3-13MPa, the cohesion is 3-30MPa, and the internal friction angle is 20-35. The density of equivalent drilling fluid is 2.20-2.22 g / cm ~ 3, the density of formation pore pressure equivalent drilling fluid is 1.05-1.10 g / cm ~ 3, and the maximum horizontal stress is 2.35-2.55 g / cm ~ 3, respectively. The minimum horizontal stress is about 2.00-2.20 g/cm3. (3) from the viewpoint of mechanics, the stability of borehole wall is evaluated, the stress distribution around the well is analyzed, and the prediction model of formation collapse pressure and fracture pressure based on Mohr-Coulomb strength criterion is established. The formation collapse pressure and fracture pressure profile are calculated. The results show that the maximum collapse pressure of Permian is 1.45 g / cm ~ 3, and the contradiction between high collapse pressure and relatively low drilling fluid density is the mechanical reason of shaft wall instability. The fracture pressure is between 1.70 and 1.90 g/cm3. (4) the mud of Triassic PDC bit is selected and discharged optimally, the countermeasure of using drilling fluid cleaner is studied, and the stability of Permian wellbore is studied. Drilling fluid density design and optimal selection of drilling fluid inhibitors were studied. The results show that the use management of cleaning agent in block should be strengthened to reduce mud ladle, and drilling fluid discharge should reach 33L / s in 21.59cm well and 42 L / s in 24.13cm well. The design density of Permian drilling fluid is 1.50 g / cm ~ 3, and the optimal inhibitor combination is 3%KCL 0.4%KPAM _ 2.
【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】：TE28
【引证文献】
相关会议论文 前1条
1 楼一珊;庄锦江;黄荣樽;;岩石动静弹性参数相关性研究及其在石油工程中的应用[A];岩石力学在工程中的应用——第二次全国岩石力学与工程学术会议论文集[C];1989年
，本文编号：2426944
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