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Optimization Techniques for Stimulation Design of Horizontal Wells of Heterogeneous Tight Oil in Northern Songliao Basin

Jin Chengzhi, Yang Dong, Zhang Yongping, Huo Fenglong, Gu Mingyong   

  1. PetroChina Daqing Oilfield Company Limited
  • Online:2014-12-15 Published:2014-12-15

Abstract: The tight oil reservoir in the northern part of Songliao Basin is the sedimentation of semi-deep to deep lacustrine facies mingled with delta frontal subfaices and fluvial facies. It is characterized as decentralized longitudinally, instable horizontally, small in sweet-point scale, poor fl at connectivity, changeable in physical properties, and different in oil bear properties. The mechanical difference, caused by strong heterogeneity, makes fractures extend non-uniformly and leads to more fracturing sections and a larger fracturing scale so that high requirements are set on the proppant, raw materials and operational facilities. Equal fractural spacing fracturing design is not suitable in this region. To solve this problem, the techniques for stimulation design have been developed for optimization of fractural spacing, division of fracturing sections, optimization of perforation, optimization of fractural length and height and optimization of fractural conductivity so that optimization of fractural system can be achieved in volumetric fracturing of heterogeneous reservoirs. Meanwhile, optimization arrangement of fracturing fl uid, proppant and surface facilities met the requirements for a large-scale volumetric renovation of tight oil reservoir in northern part of Songliao Basin. A total of 10 wells with 97 sections were tested on the fi eld. The single-well production reached 40 m3/don average, 17 times as high as that from the neighboring straight wells with the same conditions of physical properties. Continental heterogeneous tight oil reservoirs were brought under effective renovation. The techniques are of a great signifi cance to Daqing to increase tight oil reserves and production.