基于复杂缝网模拟的页岩气水平井立体开发效果评价新方法——以四川盆地南部地区龙马溪组页岩气为例  

A new method for evaluating tridimensional development effect of shale gas horizontal wells based on complex fracture network simulation: A case study of Longmaxi Formation shale gas in the southern Sichuan Basin

作　　者：王军磊[1] 贾爱林[1] 位云生[1] 王建君 黄小青 李林 于伟 WANG Junlei;JIA Ailin;WEI Yunsheng;WANG Jianjun;HUANG Xiaoqing;LI Lin;YU Wei(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China;PetroChina Zhejiang Oilfield Company,Hangzhou,Zhejiang 310000,China;University of Texas at Austin,Austin 78712,USA)

机构地区：[1]中国石油勘探开发研究院,北京市100086 [2]中国石油浙江油田公司 [3]得克萨斯大学奥斯汀分校

出　　处：《天然气工业》2022年第8期175-189,共15页Natural Gas Industry

基　　金：中国石油天然气股份有限公司“十四五”前瞻性基础性科技项目“复杂天然气田开发关键技术研究”(编号:2021DJ1704)。

摘　　要：如何合理表征三维人工裂缝形态及延伸范围以及模拟压后复杂缝网产能特征是论证、评价页岩气立体井网开发效果的关键。为此,以川南地区页岩气为对象,基于三维地质模型、天然裂缝模型和地质力学模型,模拟了人工裂缝形态及其与天然裂缝的空间配置关系,分析了三维人工裂缝在缝长和缝高方向的延伸规律,然后根据压后复杂裂缝网络形态,设计了同层井网、立体井网等不同的井网部署模式,使用嵌入式离散裂缝模型耦合数值模拟器模拟了立体井网全生命周期内各气井的生产动态,并结合智能化历史拟合技术反演获得了给定井网结构下的裂缝网络参数。研究结果表明:(1)人工裂缝在高度方向上延伸受到明显抑制,限制了同层井网对于纵向储量的控制程度;(2)立体井网在提高储量整体动用程度的同时降低了平面井间干扰强度,为井距缩小提供调整空间;(3)以裂缝压窜和井间压力干扰为判别机制,通过厘清人工裂缝与立体井距配置关系可以获得最优配置模式,从而进一步提高立体井网开发效果。结论认为:(1)川南地区页岩气适宜采用错层开发的小井距模式,该模式易形成“短缝长、低缝高”的造缝效果,井组采收率预计可提高5%~10%;(2)该方法可较好地评价页岩气立体井网开发效果,为页岩气藏(井)产能的高效评价和开发技术政策优化提供了技术支撑。The key to demonstrating and evaluating the development effect of shale gas tridimensional well pattern is how to reasonably characterize the morphology and propagation range of 3D hydraulic fractures and simulate the postfrac productivity characteristics of complex fracture networks. Taking the shale gas in the southern Sichuan Basin as the research object, this paper simulates the morphology of hydraulic fractures and its spatial relationship with natural fractures by virtue of 3D geological model, natural fracture model and geomechanical model, and then analyzes the propagation laws of 3D hydraulic fractures in the directions of fracture length and fracture height. Based on the morphology of complex fracture networks after fracturing, different well pattern deployment modes are designed, such as single-layer well pattern and tridimensional well pattern. Finally, the production performance of each well in the whole life cycle of tridimensional well pattern is simulated by using the embedded discrete fracture model coupling with the numerical simulator, and the fracture network parameters under the given well pattern structure are obtained trough inversion by means of the intelligent history matching technology. And the following research results are obtained. First, the propagation of hydraulic fractures in the direction of the height is inhibited greatly, which restricts the control degree of single-layer well pattern to vertical reserves. Second, the tridimensional well pattern decreases the areal interwell interference intensity while improving the overall reserve producing degree, so as to provide accommodation space for well spacing reduction. Third, the optimal configuration mode between hydraulic fracture and tridimensional well spacing can be figured out by analyzing their relationships with fracture hit and interwell pressure interference as the discrimination mechanism, so as to improve the development effect of tridimensional well pattern further. In conclusion, the small well spacing mode of stagger

关 键 词：四川盆地南部地区 龙马溪组 页岩气 天然裂缝 裂缝网络 嵌入式裂缝模型 裂缝压穿 缝长—井距匹配模式 

分 类 号：TE37[石油与天然气工程—油气田开发工程]