对于具有应力敏感的裂缝性油藏,在开发过程中因地层压力下降导致基质与裂缝体积缩小,渗流能力降低.如何有效抑制这种油藏特性对开发效果和最终采收率的影响,是制定裂缝性油藏开发策略的关键.本文以渤海某裂缝性油藏为例,对应力敏感与注水时机及地层压力保持水平之间的密切关系进行分析和研究.结果表明:在不考虑应力敏感时,裂缝性油藏合理注水时机为地层压力降至饱和压力时实施注水;在考虑应力敏感时,裂缝性油藏合理注水时机由应力敏感程度决定.当油藏压力降至饱和压力处渗透率保留率在80%以上时,注水时机为地层压力降至饱和压力时实施注水.否则,必须在原始地层压力实施注水.同时,裂缝性油藏合理地层压力保持水平应该维持合理注水时机下的地层压力不变,但考虑到后期提液、打井等挖潜措施及综合调整的实施,可根据实际情况适当提高.
For stress-sensitive fractured reservoirs, the decrease of seepage ability is inevitable due to reduction of pore volume caused by formation pressure drop in the process of development. How to effectively restrain the influence of it on the development effectiveness and ultimate recovery is the key to developing fractured reservoir development strategies. This paper takes a fractured reservoir in Bohai Oilfield as an example to study the effects of stress sensitivity on reasonable water-flooding time and formation pressure level. The results show that without consideration of stress sensitivity, the reasonable water-flooding time was when the formation pressure dropped to saturation pressure, while with consideration of stress sensitivity, it was determined by the degree of stress sensitivity. When the retention rate of permeability was above 80% at reservoir saturation pressure, the reasonable waterflooding time was also when the formation pressure dropped to saturation pressure. Otherwise, water-flooding must be carried out at original reservoir pressure. Meanwhile, the formation pressure for reasonable water-flooding time should be kept constant, or slightly elevated with consideration of subsequent developing measures and comprehensive adjustment.
[1] 张李, 张茂林, 梅海燕, 等. 低渗透气藏应力敏感性分析及对开采的影 响[J]. 特种油气藏, 2007, 14(3): 55-58. Zhang Li, Zhang Maolin, Mei Haiyan, et al. Stress sensibility analysis of low permeability gas reservoir and its influence on exploitation[J]. Special Oil and Gas Reservoir, 2007, 14(3): 55-58.
[2] 阮敏, 王连刚. 低渗透油田开发与压敏效应[J]. 石油学报, 2002, 23 (3): 73-76. Yuan Min, Wang Liangang. Low permeability oilfield development and pressure sensitive effect[J]. Acta Petrolei Sinica, 2002, 23(3): 73-76.
[3] 阮敏. 压敏效应对低渗透油田开发的影响[J]. 西安石油学院学报: 自 然科学版, 2001, 16(4): 40-45. Yuan Min. Effect of pressure-sensitive damage on the development of low permeability reservoirs[J]. Journal of Xi'an Petroleum Institute: Natural Science Edition, 2001, 16(4): 40-45.
[4] 兰林, 康毅力, 陈一健, 等. 储层应力敏感性评价实验方法与评价指标 探讨[J]. 钻井液与完井液, 2005, 22(3): 1-4. Lan Lin, Kang Yili, Chen Yijian, et al. Discussion on evaluation methods for stress sensitivities of low permeability and tight sandstone reservoirs[J]. Drilling Fluid & Completion Fluid, 2005, 22(3): 1-4.
[5] Zhu S Y. Experiment research of tight sandstone gas reservoir stress sensitivity based on the capillary bundle mode[C]. SPE Annual Technical Conference and Exhibition, New Orleans, USA, September 30-October 2, 2013.
[6] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理 委员会. SY/T 5358—2002 储层敏感性流动实验评价方法[S]. 北京: 石油工业出版社, 2008. The people's Republic of China State Administration of Quality Supervision Inspection and quarantine, Chinese National Standardization Management Committee. SY/T 5358—2002 Formation damage evaluation by flow test[S]. Beijing: Petroleum Industry Press, 2008.
[7] 李闽, 乔国安, 陈昊. 低渗砂岩储层岩石应力敏感实验与理论研究[J]. 钻采工艺, 2006, 29(4): 91-93. Li Min, Qiao Guoan, Chen Hao. Experimental and theoretical study on rock stress- sensitivities in low permeability sandstone[J]. Drilling & Production Technology, 2006, 29(4): 91-93.
[8] Tadesse W, John A, Najeeb A, et al. Pressure and rate analysis of fractured low permeability gas reservoirs: numerical and analytical dualporosity models[C]. SPE Middle East Unconventional Gas Conference and Exhibition, Muscat, Oman, January 28-30, 2013.
[9] Sarath P K, Turgay E. Analysis of production decline characteristics of a multisatge hydraulically fractured horizontal well in a naturally fractured reservoir[C]. SPE Eastern Regional Meeting, Lexington, Kentucky, USA, October 3-5, 2012.
[10] Xu F, Guo X, Zhang Y, et al. Case study: Numerical simulation on formation damage in low-permeability gas reservoir[C]. Nigeria Annual International Conference and Exhibition, Abuja, Nigeria, July 30- August 3, 2011.
[11] Lei Q, Xiong W, Yuan J R, et al. Analysis of stress sensitivity and its influence on oil production from tight reservoirs[C]. SPE Eastern Regional Meeting, Lexington, Kentucky, USA, October 17-19, 2007.
[12] Sun H D, Xiao X J, Yang J P, et al. Study on productivity evaluation and performance prediction method of over-pressured, stress-sensitive gas reservoirs[C]. SPE Asia Pacific Oil & Gas Conference and Exhibition, Jakarta, Indonesia, October 30-November 1, 2007.
[13] Alcalde O R, Teufel L W. Diagnosis of formation damage by rock deformation/compaction through numerical well- test simulations[C]. SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, USA, February 15-17, 2006.
[14] 谢晓庆, 姜汉桥, 王全柱, 等. 低渗透油藏压敏效应与注水时机研究[J]. 石油学报, 2009, 30(4): 574-582. Xie Xiaoqing, Jiang Hanqiao, Wang Quanzhu, et al. Discussion on pressure- sensitivity effect and water- flooding timing in lowpermeability reservoir[J]. Acta Petrolei Sinica, 2009, 30(4): 574-582.
[15] 王道富, 李忠兴, 赵继勇, 等. 低渗透油藏超前注水理论及其应用[J]. 石油学报, 2007, 28(6): 78-81. Wang Daofu, Li Zhongxing, Zhao Jiyong, et al. Advance waterflooding theory for low-permeability reservoirs and its application[J]. Acta Petrolei Sinica, 2007, 28(6): 78-81.
[16] 于忠良, 熊伟, 高树生, 等. 致密储层应力敏感性及其对油田开发的 影响[J]. 石油学报, 2007, 28(4): 95-98. Yu Zhongliang, Xiong Wei, Gao Shusheng, et al. Stress sensitivity of tight reservoir and its influence on oilfield development[J]. Acta Petrolei Sinica, 2007, 28(4): 95-98.
