压裂水平井多井干扰数值试井分析

Numerical Well Testing Analysis of Multi-well Interference from Multi-fractured Horizontal Wells

何佑伟 陈樟池 汤勇 赵国庆 吴柯宇

HEYouwei CHENZhangchi TANGYong ZHAOGuoqing WUKeyu

油气藏地质及开发工程全国重点实验室·西南石油大学, 四川 成都 610500 西南石油大学石油与天然气工程学院, 四川 成都 610500

State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Petroleum Engineering School, Southwest Petroleum University, Chengdu, Sichuan 610500, China

实际油气藏相邻井之间存在井间干扰，特别是致密（非常规）油气藏井间距较小，井间可能通过压裂缝或者天然缝沟通，井间干扰不容忽略。目前试井模型以单井静态裂缝为主，多井动态缝网条件下的试井模型不成熟，需要研究多井干扰数值试井方法，分析邻井以及缝网参数对观察井压力特征的影响。为此，建立了压裂水平井复杂缝网井间干扰数值试井模型，验证了模型精度与优势。分析了井间干扰、邻井产量、裂缝宽度非均匀变化、缝网连通程度、压裂裂缝和天然裂缝导流系数对不稳定压力特征的影响。当天然裂缝较发育时，井间连通性较好，邻井影响裂缝线性流阶段、裂缝径向流、椭圆流阶段以及系统径向流阶段；当天然裂缝发育程度低时，邻井主要影响观察井的中后期压力特征。建立的压裂水平井多井干扰数值试井模型能够实现复杂缝网、不规则产气、井间干扰等条件下的不稳定压力计算，能够更清晰地体现出基质、裂缝等各个网格及早期的压力差异，丰富了非常规油气藏数值试井分析方法。

Interwell interference cannot be ignored especially in tight and unconventional oil and gas reservoirs since adjacent wells may be communicated through natural fractures or even hydraulic fractures due to tight well spacing. Currently, the well testing models are focused on an individual well with simple fractures. It lacks the well testing model considering multiple wells with complex fracture networks. It is necessary to develop the numerical well testing method of multi-well interference, and analyze the impact of adjacent wells and fracture network parameters on the pressure transient behavior of the observed wells. Thus, this work proposes a numerical well test model of multiple fractured horizontal wells with complex fracture networks. The accuracy and advantages of the proposed model are validated. The effect of well interference, adjacent well's production, nonuniform fracture aperture, fracture networks, fracture conductivity of hydraulic and natural fractures on the pressure transient behavior are analyzed. Well-developed natural fractures lead to better interwell connectivity, and the adjacent wells influence the fracture linear flow, fracture radial flow, elliptical flow, and final radial flow period. When the natural fractures are not well developed, the adjacent wells affect the middle and late pressure behavior of the observation well. The developed multiwell numerical well testing model in this work considers the complex fracture networks, irregular fractures, nonuniform gas production profile, and interwell interference, which can characterize early pressure behavior and pressure differences among matrix, fracture and other grids more clearly. It enriches the numerical well testing analysis method of tight and unconventional oil and gas reservoirs.

10.11885/j.issn.1674-5086.2023.09.08.02