英雄岭页岩油藏水力压裂效果评价方法及应用

Evaluation Method and Application of Hydraulic Fracturing Effect in Yingxiongling Shale Reservoir

摘要: 页岩油藏多段多簇水平井压裂缝网结构的复杂化使得准确评价压裂效果难度大。针对压裂施工过程中数据来源和解释原理差异性大，评价方法间各有优劣且可互相补充，需要综合考虑地质条件、压裂参数和评价目标等因素，提出联合多种评价方法进行综合评估。以英雄岭英页2平台H14-2井为例，采用压裂停泵高频压力测试、示踪剂测试、井中微地震测试等联合评价方法对压裂缝规模、压裂缝渗流特征、压裂缝产能进行压裂效果评价；联合录测井对岩性岩相的解释成果，深层揭示油相示踪剂反映的压裂水平井段供液存在差异化动用的特征。综合评估表明，停泵压降法反演得到的裂缝规模可以通过微地震验证并补充，示踪剂返排浓度曲线结合微地震的三种缝网模型可以评价压裂水平井产能水平，压裂段动用状况先启动的岩性主要为纹层状灰云岩，后启动的岩性主要为层状灰云岩。采用联合评价方法可以满足页岩油井压裂改造效果评价的挑战，并为页岩油藏的高效开发提供科学依据。

Abstract: In shale reservoirs, due to the complexity of the fracture network structure of multi-section and multi-cluster horizontal wells, it is difficult to accurately evaluate the fracturing effect. In response to the problem of the great variability of data sources and interpretation principles in the process of fracturing construction, each evaluation method has its own advantages and disadvantages and can be complementary to each other. It is necessary to consider factors such as geological conditions, fracturing parameters and evaluation objectives, and to propose a comprehensive evaluation by combining multiple evaluation methods. Taking YY2H14-2 well as an example, joint evaluation methods such as high-frequency pressure test of fracturing stop pump, tracer test and microseismic test in the well were adopted to evaluate the fracturing effect on the fracture scale, seepage characteristics of the fracture and fracture production capacity. Combined with the results of logging interpretation of lithology and lithofacies, it deeply reveals the characteristics of differential utilization of liquid supply in fractured horizontal well section reflected by oil phase tracer. The comprehensive evaluation shows that the fracture scale obtained from the inversion of the stop-pump pressure drop method can be verified and supplemented by microseismic, the tracer flowback concentration curve combined with the three types of fracture network models from microseismic can evaluate the productivity level of the fractured horizontal wells. The lithology of the first start-up of the fracturing section is mainly lamellar limestone, and the lithology of the second start-up is mainly lamellar limestone. The joint evaluation method can meet the challenge of evaluating the fracturing effect of shale oil wells and provide a scientific basis for the efficient development of shale reservoirs.