Study on the Effects of Changes in Pore Pressure on Wellbore Stability

doi:10.11885/j.issn.1674-5086.2016.07.09.05

Abstract

Abstract: Long-term injection/projection operations cause large fluctuations in pore pressure, which in turn cause relatively large changes in rock strength and ground stress in the strata compared to the initial stage of mining. Furthermore, the complexity in the horizontal distribution of pore pressure induces and exacerbates wellbore instability and results in frequent occurrences of complex downhole situations. We carried out a combined theoretical and experimental study to understand the effects of pore pressure changes on the rock strength and stratum collapse pressure of sandstone strata. The results show that:(1) Rock strength is negatively correlated with pore pressure. As pore pressure increases, stratum rock strength and elastic modulus show a linear decrease. (2) Changes in pore pressure affect wellbore stability. Fractures, water injection, and polymer injection operations result in increased pore pressure around the well, which exacerbates wellbore instability. In addition, pressure-attenuated mining of oil and gas within a certain range decreases the stratum collapse pressure, which is beneficial for maintaining wellbore stability.

Key words: wellbore stability, pore pressure, rock strength, collapse pressure

CLC Number:

TE243

LI Wei, LIANG Lixi, LIU Xiangjun, WANG Tao. Study on the Effects of Changes in Pore Pressure on Wellbore Stability[J]. 西南石油大学学报(自然科学版), 2017, 39(6): 63-68.

0
/ / Recommend

Add to citation manager EndNote|Ris|BibTeX

URL: http://journal15.magtechjournal.com/Jwk_xnzk/EN/10.11885/j.issn.1674-5086.2016.07.09.05

http://journal15.magtechjournal.com/Jwk_xnzk/EN/Y2017/V39/I6/63

References

[1] 姜伟. 海上密集丛式井组再加密调整井网钻井技术探索与实践[J]. 天然气工业,2011,31(1):69-72,114. doi:10.3787/j.issn.1000-0976.2011.01.015 JIANG Wei. Research and practices of re-infill drilling technology for offshore close-spaced cluster-well pads[J]. Natural Gas Industry, 2011, 31(1):69-72, 114. doi:10.3787/j.issn.1000-0976.2011.01.015
[2] 刘天科. 胜利油田老区调整井钻井井控技术[J]. 石油钻采工艺,2011(3):9-11. doi:10.13639/j.odpt.2011.03.011 LIU Tianke. Application of well control technology on adjustment wells in matured areas of Shengli Oilfield[J]. Oil Drilling &Production Technology. 2011(3):9-11. doi:10.13639/j.odpt.2011.03.011.
[3] 张洪生,宋振清,石晓兵. 准噶尔盆地八区调整井高效安全钻井技术[J]. 天然气工业,2005,25(7):56-58. ZHANG Hongsheng, SONG Zhenqing, SHI Xiaobing. High efficiency and safety drilling techniques of adjustment wells in the eighth region of ZHUNGE'ER Basin[J]. Natural Gas Industry, 2005, 25(7):56-58.
[4] 袁俊亮,邓金根,蔚宝华,等. 油藏开发对井壁稳定性的影响研究[J]. 钻采工艺,2012,35(5):4-7. YUAN Junliang, DENG Jinge, YU Baohua, et al. Effect of pressure depletion on wellbore stability with consideration of in-situ stress orientation variation[J]. Drilling &Production Technology, 2012, 35(5):4-7.
[5] 杨学德,何启贤,刘畅,等. 注水井对调整井钻井的影响及对策[J]. 石油钻探技术,2001,29(2):16-18. YANG Xuede, HE Qixian, LIU Chang. Water injection effect on the adjustment well drilling and counter measures[J]. Petroleum Drilling Techniques, 2001, 29(2):16-18.
[6] 王勇茗,吴学升,周文军. 安塞地区加密井地层压力预测研究[J]. 西南石油大学学报(自然科学版),2016, 38(4):123-129. doi:10.11885/j.issn.1674-5086.2014.06.09.03 WANG Yongming, WU Xuesheng, ZHOU Wenjun. Research on formation pressure prediction in Ansai Area infilling[J]. Journal of Southwest Petroleum University (Science &Technology Edition), 2016, 38(4):123-129. doi:10.11885/j.issn.1674-5086.2014.06.09.03
[7] 赵少伟,范白涛,钟立国,等. 注采条件下加密调整井压力预测与调控技术研究及应用[J]. 中国海上油气, 2017,29(1):99-104. doi:10.11935/j.issn.1673-1506.2017.01.015 ZHAO Shaowei, FAN Baitao, ZHONG Liguo, et al. Research and application of pressure prediction and control technology for infill adjustment wells during injectionproduction operations[J]. China offshore oil and gas, 2017, 29(01):99-104. doi:10.11935/j.issn.1673-1506.2017.01.015
[8] 潘林华,张士诚,程礼军,等. 围压-孔隙压力作用下碳酸盐岩力学特性实验[J]. 西安石油大学学报(自然科学版),2014,29(5):17-20. PAN Linhua, ZHANG Shicheng, CHENG Lijun, et al. Experimental study on mechanical property of carbonate under the effect of confining pressure and pore pressure[J]. Journal of Xi'an Shiyou University (Natural Science Edition), 2014, 29(5):17-20+4-5.
[9] 刘向君,申剑坤,梁利喜,等. 孔隙压力变化对岩石强度特性的影响[J]. 岩石力学与工程学报,2011,30(S2):3457-3463. LIU Xiangjun, SHEN Jiankun, LIANG Lixi, et al. Effects of pore pressure on rocks strength properties[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(S2):3457-3463.
[10] 刘琦,卢耀如,李晓昭. 孔隙水压力对岩石力学参数的影响[J]. 地球学报,2008,29(5):660-664. LIU Qi, LU Yaoru, LI Xiaozhao. The effect of the pore water Pressure on the rock mechanics parameters[J]. Acta geo scientica sinica, 2008, 29(5):660-664.
[11] 何世明,陈俞霖,马德新,等. 井壁稳定多场耦合分析研究进展[J]. 西南石油大学学报(自然科学版),2017, 39(2):81-92. doi:10.11885/j.issn.1674-5086.2015.05.16.03 HE Shiming, CHEN Yulin, MA Dexin. et al. A review on wellbore stability with multi-field coupling analysis[J]. Journal of Southwest Petroleum University (Science &Technology Edition), 2017, 39(2):81-92. doi:10.11885/j.issn.1674-5086.2015.05.16.03
[12] 王倩,周英操,刘玉石,等. 控压钻井过程中泥页岩井壁破坏分析[J]. 天然气工业,201131(8):80-85,136. WANG Qian, ZHOU Yingcao, LIU Yushi, et al. Wellbore failure in shale wells during managed pressure drilling[J]. Natural Gas Industry, 2011, 31(8):80-85, 136.
[13] 冯永存,李晓蓉,蔚宝华,等. 压力衰减储层直井井壁稳定性研究[J]. 长江大学学报(自然科学版),2011, 8(10):50-53. doi:10.3969/j.issn.1673-1409.2011.10.015 FENG Yongcun, LI Xiaorong, WEI Baohua, et al. Research on wellbore stability of vertical wells in pressure depleted reservoris[J]. Journal of Yangtze University (Natural Science Edition), 2011, 8(10):50-53. doi:10.3969/j.issn.1673-1409.2011.10.015
[14] 梁利喜. 深部应力场系统评价与油气井井壁稳定性分析研究[D]. 成都:成都理工大学,2008. LIANG Lixi. Research on deep in-situ stress field and wellbore stability[D]. Chengdu:Chengdu University of Technology, 2008.
[15] 李光泉. 深部地质环境对井壁稳定性的影响[J]. 西南石油大学学报(自然科学版),2012,34(1):103-107. doi:10.3863/j.issn.1674-5086.2012.01.016 LI Guangquan. The Impact of geological environment on wellhole stability[J]. Journal of Southwest Petroleum University (Science &Technology Edition), 2012, 34(1):103-107. doi:10.3863/j.issn.1674-5086.2012.01.016
[16] 梁利喜,丁乙,刘向君,等. 硬脆性泥页岩井壁稳定渗流力化耦合研究[J]. 特种油气藏,2016,23(2):140-143,158. doi:10.3969/j.issn.1006-6535.2016.02.034 Liang Lixi, Ding Yi, Liu Xiangjun, et al, Seepagemechanochemistry coupling of wellbore stability in hardbrittle shale[J]. Special Oil &Gas Reservoirs, 2016, 23(2):140-143, 158. doi:10.3969/j.issn.1006-6535.2016.02.034
[17] 张明明,梁利喜,刘向君. 不同岩石剪切破坏判据对井壁坍塌压力的影响分析[J]. 岩石力学与工程学报,2017,36(S1):3485-3491. doi:10.13722/j.cnki.jrme.2016.0843 ZHANG Mingming, LIANG Lixi, LIU Xiangjun. Impact analysis of different rock shear failure criteria to wellbore collapse pressure[J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(S1):3485-3491. doi:10.13722/j.cnki.jrme.2016.0843
[18] 梁利喜,刘向君. 基于霍克布朗准则评价页岩气井井壁稳定性[J]. 西南石油大学学报(自然科学版), 2014,36(5):105-110. doi:10.11885/j.issn.1674-5086.2014.03.26.06 LIANG Lixi, LIU Xiangjun. Research on wellbore stability of shale gas based on Hoek-Brown criterion[J]. Journal of Southwest Petroleum University (Science &Technology Edition), 2014, 36(5):105-110. doi:10.11885/j.issn.16745086.2014.03.26.06.