裂缝高度延伸诊断与控制技术

Diagnosis method of artificial fracture vertical extension and the control technique of fracture height in fracturing or acid fracturing

缝高控制是压裂酸化改造成功的关键因素之一,而缝高控制又与裂缝高度延伸诊断密切相关,影响裂缝高度延伸的因素主要归结为可控和不可控因素两类,从地层应力、岩石物性和施工参数等方面对裂缝高度延伸的主要影响因素进行分析,提出了根据裂缝延伸k判据、裂缝净压力与储层应力差的比值、裂缝净压力双对数曲线形态等三种裂缝高度延伸诊断方法。结合压裂酸化工艺特点,从降低地层破裂压力、人工隔层控缝高、降滤失控缝高、工作液体系控制、平衡酸压工艺、完井方案优化、施工压力监控等方面讨论了压裂酸化过程中的各种裂缝高度控制技术。

Controlling the fracture height is one of the key factors that determine fracturing/acid-fracturing successful or not. The diagnosis of artificial fracture vertical extension is interdependent to the control technique. In these aspects, researcher made seldom work. The dominant factors that affect fracture height may include controllable factor and uncon- trollable factor. In this paper, analysis is conducted in aspects of in-situ stress influences, rock physical property and treatment parameters. The paper presents the diagnosis of fracture vertical extension, include fracture extension ＂k＂ criterion, the ratio of fracture net pressure and in-situ stress difference, fracture net pressure double logarithmic curve. Combining with fracturing/acid-fracturing treatment characteristics, discussions are conducted also from perspectives of control fracture height by reducing stratum bursting pressure, artificial insulation, fluid loss control, as well as from the liquid system, the well completion plan optimization, the treatment pressure monitoring and so on.