致密油藏大排量注水吞吐技术及参数优化研究  

Huff-n-puff technology and parameter optimization of large displacement water injection in tight oil reservoir

作　　者：张益[1] 宁崇如 陈亚舟 姬玉龙 赵立阳 王爱方 黄晶晶 于凯怡 ZHANG Yi;NING Chongru;CHEN Yazhou;JI Yulong;ZHAO Liyang;WANG Aifang;HUANG Jingjing;YU Kaiyi(Key Laboratory of Oil and Gas Well and Reservoir Seepage and Rock Mechanics in Shaanxi Province,Xi'an Shiyou University,Xi'an,Shaanxi 710065,China;Xinjiang Yaxin Coalbed Methane 156 Exploration Co.,Ltd.,Urumqi,Xinjiang 841100,China;PetroChina Changqing Oilfield Branch Third Oil Production Plant,Yinchuan,Ningxia 750000,China;PetroChina Changqing Oilfield Branch Fourth Oil Production Plant,Jingbian,Shaanxi 718599,China)

机构地区：[1]西安石油大学陕西省油气井及储层渗流与岩石力学重点实验室,陕西西安710065 [2]新疆亚新煤层气一五六勘查有限责任公司,新疆乌鲁木齐841100 [3]中国石油长庆油田分公司第三采油厂,宁夏银川750000 [4]中国石油长庆油田分公司第四采油厂,陕西靖边718599

出　　处：《油气藏评价与开发》2024年第5期727-733,共7页Petroleum Reservoir Evaluation and Development

基　　金：陕西省重点研发计划项目“高含水油藏CO_(2)驱开发过程中的渗流及碳埋存规律研究与应用”(2023-YBGY-316)。

摘　　要：针对致密油藏水平井自然渗吸采收率低和长期衰竭开发后期地层能量如何补充的难题,在储层基本特征、致密油藏注水吞吐采油机理的基础上,提出了大排量水平井注水吞吐。以鄂尔多斯盆地长7段致密油藏为研究对象,选取天然岩心和人造岩心相结合方式,利用核磁共振等方法,通过室内注水吞吐实验研究了自然渗吸和不同注水速度下吞吐动态渗吸的作用范围和微观孔隙动用特征,分析了排量对孔隙动用情况的影响,并开展了焖井时间影响实验,最后利用数值模拟方法对压裂水平井注水吞吐开发的注水量、焖井时间参数进行优化。研究表明:小排量时,注水吞吐主要动用的是大孔隙,中小孔隙动用较低;大排量时,注水吞吐不仅动用了大孔隙,且中小孔隙动用明显提高,使得整体的采收率出现较大增加。随着焖井时间的延长,油水置换作用越充分,使得注水吞吐采出程度越高,但其提高的程度逐渐稳定。对A9井进行数值模拟优化,得到最佳日注水量为900 m^(3),最佳焖井时间为24 d,在矿场试验取得成功,初期日增油2.11 t,有效期365 d,累计增油770 t。To address the issue of low natural imbibition recovery in horizontal wells within tight reservoirs and the challenge of replenishing formation energy during extended depletion phases,a strategy involving water injection huff and puff in large displacement horizontal wells was proposed.This approach builds on the fundamental characteristics of reservoirs and the established mechanisms of water injection huff and puff oil production in tight reservoirs.The research focused on the Chang-7 tight reservoir in Ordos Basin,employing a combination of natural and artificial cores.This study explored the range of natural imbibition and the dynamics of water injection and huff and puff across various displacements.Methods like nuclear magnetic resonance were used to analyze the characteristics of microscopic pore production,the impact of displacement on pore productivity,and the effects of soaking time.The findings reveal that with smaller displacements,mainly large pores are utilized for water injection,resulting in minimal engagement of small and medium pores.Conversely,higher water injections significantly enhance the involvement of small and medium-sized pores,thus substantially boosting the overall recovery rate.Additionally,as the simmering time is extended,the oil-water displacement effect increases,enhancing the degree of recovery through water injection huff and puff,though the rate of improvement eventually stabilizes.Numerical simulation was used to optimize the parameters for water injection huff and puff development in fracturing horizontal wells.For Well-A9,the optimal parameters were identified as a daily water injection rate of 900 m^(3)and a simmering time of 24 days.The field test confirmed the effectiveness of these parameters,with an initial daily oil increase of 2.11 tons,an effective period of 365 days,and a cumulative oil increase of 770 tons.

关 键 词：大排量注水吞吐 致密油藏 水平井 核磁共振 数值模拟 

分 类 号：TE357.6[石油与天然气工程—油气田开发工程]