常压页岩气低成本高效压裂技术对策

常压页岩气在渝东南地区广泛分布，具有岩石脆性好、裂隙原始尺度小、含气丰度低、吸附气比例较高、压力系数低等特点；压裂面临裂缝复杂性低（单一缝占比较大），改造体积有限，长期导流能力保持不足等难题，造成压后产量低且递减快，影响了常压页岩气的经济有效开发。从压裂工程角度出发，以提高单位岩石体积内裂缝有效改造体积及多尺度裂缝长期导流能力为前提，在压裂增效基础上进一步降低工程成本为目标，提出高效压裂技术对策。①压裂增效技术:提出页岩平面射孔模式，提高了每簇的改造强度及诱导应力作用范围，裂缝复杂程度及SRV（18%～20%）得到提升，增产效果明显（三年累产量同比提高28.5%）；提出多尺度造缝及交替注酸扩缝技术，进一步增大有效改造体积及裂缝复杂性；提出多元组合加砂压裂模式，提高支撑剂在裂缝内铺置广度及充填度，提高压后长期导流能力。③压裂降本技术:通过压裂造缝机理精细模拟研究，减少造缝中的低效液体（同比单簇节约20～25%），避免低效施工；通过一剂多效压裂液体系和混合支撑剂的综合应用，进一步降低压裂材料成本。研究结果为常压页岩气的低成本高效压裂提供了理论依据，提高了压裂实施的科学性与有效性。 

The Countermeasure of Low Cost and High Efficiency Fracturing Technology of Normal Pressure Shale Gas

The normal pressure shale gas is widely distributed in the southeast of China. It has the characteristics of low rock brittleness, low initial scale of fracture, low gas abundance, high adsorption ratio and low pressure coefficient. Fracturing is confronted with the difficulties of low crack complexity, limited transformation volume and insufficient long-term conductive ability, resulting in low production and diminishing fast, which has affected the economical and effective development of normal pressure shale gas. From the angle of the fracturing engineering, in order to improve the unit volume of fracturing and the long-term conductive ability of multi-scale fracture, on the basis of fracturing stimulation, the cost of engineering is further reduced and the countermeasure of high efficiency fracturing technique is put forward. The first countermeasure is fracturing stimulation technology. It puts forward the model of plane perforation, improve the stimulation strength and the the induced stress interference range, the degree of fracture complexity and SRV(18%-20%) is improved, the effect of stimulation is obvious(three years of production increase 28.5%). The technology of multi-scale fracture creation and alternating injection acid is proposed to further increase the effective fracturing volume and fracture complexity. The multi-component combination adding sand mode is proposed to improve the width and filling degree of the proppant in the crack, and improve the long-term conductive ability. The second countermeasure is the cost reduction technology. Through the elaborate simulation of fracture creation mechanism, the inefficient liquid was reduced(single cluster saving 20%-25%) and the inefficient fracturing construction was avoided. The cost of fracturing materials is further reduced by the comprehensive application of a multi-effect fracturing fluid system and mixed proppant. The results provide theoretical basis for low cost and high efficiency fracturing of normal pressure shale gas, and improve the science and effectiveness of fracturing.