Abstract:  In Kuqa foreland area, the natural productivity of type I wellbore is low due to the well development of fractures, large thickness and serious damage caused by leakage of drilling and completion fluids. In order to greatly increase the production of single well, the technical concept of volume acid fracturing is put forward. Based on the criterion of critical net pressure for shear activation of natural fractures, it is demonstrated that fracturing in Kuqa super-high horizontal stress difference gas reservoir can activate natural fractures in dominant orientation, with temporary plugging in fractures to increase fluid pressure in fractures, so that shear slip of previously inactivated natural fractures can form complex network fractures. The experimental results of acid-etched fracture conductivity and acid-rock reaction show that appropriate fluorine-containing slow-speed acid solution can effectively dissolve calcareous fillings, solid particles of drilling and completion fluids and etch fracture wall, improve fracture conductivity, and prove that this area has the material basis for obtaining network fracture conductivity through acid-rock reaction. Temporary blockage of fracture and perforation hole can restrain wellbore pressure, open more intervals and increase the stimulation area in the longitudinal direction. The applicability of degradable fiber ball and /or particle longitudinal layer and in fracture diverting technology in Kuqa low-porosity fractured gas reservoir was explored. 18 times of temporary plugging and diverting volume acid fracturing operations were carried out, and the stimulation effect was remarkable after fracturing. The results show that the fiber balls and fiber particles with different particle sizes have better longitudinal layer-diverting effect, and the construction pressure increases in varying degrees; while the in-fracture diverting effect of the combination of small particle size fiber balls and fiber particles is poor, only the combination of fiber balls and fiber filaments has better in-fracture diverting effect, and the construction pressure increases distinctly.

Key words:  , fractured gas reservoir, calcareous fillings, temporary blocking and diverting, volume acid fracturing, fracture network, field application 

摘要：  库车前陆区天然裂缝发育、储层较厚，但由于储层致密以及钻完井液漏失严重，导致单井自然产量较低，为提高单井产能，提出了缝网体积酸压改造技术。基于天然裂缝剪切激活的临界净压力准则，研究发现了高水平应力差下优势方位天然裂缝易被激活的规律；酸岩反应实验结果表明，含氟缓速酸液可有效溶解缝内钙质充填物、钻完井液固相颗粒及刻蚀裂缝壁面，提高裂缝导流能力，证实了该区具备通过酸岩反应获得复杂缝网导流能力的物质基础。缝口和孔眼暂堵可使井筒憋压，迫使裂缝转向，提高纵向改造动用程度。现场多次试验，压后增产效果显著，证实了纤维球和／或颗粒纵向转层和缝内转向工艺在库车低孔裂缝性气藏的适用性。