摘要
页岩储层具有基质渗透率低、天然裂缝发育复杂等特点,主要采用多段压裂水平井的方式进行开发.页岩气井的生产分为放压生产和控压生产两种方式,目前学者们普遍认为控压生产能够增加EUR,且应力敏感性是控压生产效果优于放压生产效果的主要原因.文章在考虑基质和裂缝应力敏感的基础上,进一步考虑基质岩石的蠕变效应,建立变压蠕变影响的嵌入式离散裂缝模型,通过数值模拟方法分析应力敏感和蠕变效应对不同生产方式生产效果的影响.结果表明,只考虑应力敏感时,放压生产优于控压生产,只有考虑蠕变效应时,控压生产效果才会优于放压生产,抑制页岩的蠕变效应是控压生产提高气井EUR的机理之一.随控压时长的增加,气井EUR呈现先增加后降低的趋势,控压生产存在一个最优值;基质蠕变参数越大、人工裂缝导流能力越高、基质渗透率越小、吸附体积越小、控压生产增产的效果越好.本研究从机理上解释了控压生产的增产机理,为页岩气井的生产制度优化奠定了基础.
Considering the characteristics of shale reservoirs such as the low matrix permeability and complex natural fracture development,shale gas is mainly developed by multi-stage fracturing horizontal wells.The production of shale gas wells adopts the two modes:pressure relief production and pressure control production.Currently,scholars generally believe that pressure control production can improve the EUR of shale gas wells,and stress sensitivity is the main reason why the effect of pressure relief production is worse than that of the pressure control production.In this study,besides the stress sensitivity of matrix and fracture,the creep effect of matrix is also considered,and embedded discrete fracture models under the influence of creep are established.The results show that pressure relief production is better than pressure control production when only stress sensitivity is considered,and pressure control production is better than pressure relief production only when creep effect is considered.In addition,inhibiting the creep effect of shale is one of the mechanisms of improving the EUR of shale gas wells through pressure control production.With the increase of pressure control time,the gas well EUR shows a trend of increasing first and then decreasing,and there is an optimal value for pressure control production;The larger the matrix creep parameter,the higher the conductivity of the artificial fracture,the smaller the matrix permeability,the smaller the adsorption volume,and the better the effect of pressure control on gas production This study explains the production increase mechanism through pressure control production,laying a foundation for the optimization of shale gas well production system.
作者
郭为
柳家正
张晓伟
滕柏路
康莉霞
高金亮
刘钰洋
罗万静
Guo Wei;Liu Jiazheng;Zhang Xiaowei;Teng Bailu;Kang Lixia;Gao Jinliang;Liu Yuyang;Luo Wanjing(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China)
出处
《力学学报》
EI
CAS
CSCD
北大核心
2023年第3期630-642,共13页
Chinese Journal of Theoretical and Applied Mechanics
基金
中石油科技管理部前瞻性基础性项目资助(2021DJ2005,2021DJ1902)。
关键词
页岩气
水平井
应力敏感
蠕变效应
生产制度
控压生产
shale gas
horizontal wells
stress sensitivity
creep effect
production system
pressure control production
