Xiang Huizhu, Han Guoqing, Ma Gaoqiang, Zhu Zhiyong, Zhu Liying, Peng Long
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, 18 Fuxue Road, Changping District, Beijing 102249, China.
ACS Omega. 2021 Jul 15;6(29):19222-19232. doi: 10.1021/acsomega.1c02659. eCollection 2021 Jul 27.
Trilinear flow model is an effective method to reproduce the flow behavior for horizontal wells with multistage hydraulic fracture treatments in unconventional reservoirs. However, models developed so far for transient analysis have rarely considered the inflow performance of wells. This paper introduces a new composite dual-porosity trilinear flow model for the multiple-fractured horizontal well in the naturally fractured reservoirs. The analytical solution is derived under a constant rate condition for analyzing transient pressure behaviors and generating the transient inflow performance relationships (IPRs). The plots of pressure profiles with time could provide insightful information about various flow regimes that develop throughout the entire production cycle. Sensitivity analysis of pressure and pressure derivative response was also performed by varying different parameters (such as hydraulic fracture width and permeability, reservoir configurations, etc.) and by which the impacts of different parameters on the durations of regimes as well as the productivity index can be confirmed. The main outcomes obtained from this study are as follows: (1) the ability to characterize naturally fractured reservoirs using a new composite dual-porosity trilinear flow model; (2) the application of analytical solutions of transient analysis to generate transient IPR curves for different flow regimes; (3) understanding the effect of reservoir configurations, fractures, and matrix characteristics on pressure distribution, flow regime duration, and transient IPR. More specifically, the pressure drop increases and the productivity index decreases with the decrease of the hydraulic fracture conductivity and the increase of matrix permeability and the skin factor. Also, the larger hydraulic fracture spacing and drainage area result in the later onset of the pseudo-steady-state regime. (4) A comprehensive study on transient pressure behaviors and transient inflow performance can provide valuable information to characterize the multifractured complex systems as well as some insights into the production.
三线流模型是一种用于非常规油藏中多级水力压裂水平井流动行为再现的有效方法。然而，迄今为止开发的用于瞬态分析的模型很少考虑井的流入动态。本文针对天然裂缝油藏中的多裂缝水平井引入了一种新的复合双孔隙度三线流模型。在定流量条件下推导了解析解，用于分析瞬态压力行为并生成瞬态流入动态关系（IPR）。压力剖面随时间的曲线可以提供关于整个生产周期中各种流动状态的有价值信息。还通过改变不同参数（如水力裂缝宽度和渗透率、油藏结构等）对压力和压力导数响应进行了敏感性分析，由此可以确定不同参数对各流动状态持续时间以及产能指数的影响。本研究获得的主要成果如下：（1）利用新的复合双孔隙度三线流模型表征天然裂缝油藏的能力；（2）应用瞬态分析的解析解生成不同流动状态下的瞬态IPR曲线；（3）了解油藏结构、裂缝和基质特性对压力分布、流动状态持续时间和瞬态IPR的影响。更具体地说，随着水力裂缝导流能力的降低、基质渗透率和表皮系数的增加，压力降增大，产能指数降低。此外，较大的水力裂缝间距和泄油面积会导致拟稳态流动状态的起始时间延迟。（4）对瞬态压力行为和瞬态流入动态进行全面研究，可以为表征多裂缝复杂系统提供有价值的信息，并对生产提供一些见解。
