China Petroleum Exploration ›› 2019, Vol. 24 ›› Issue (1): 123-128.DOI: 10.3969/j.issn.1672-7703.2019.01.013

• PETROLEUM ENGINEERING • Previous Articles     Next Articles

Optimization technology and application of horizontal well trajectory drilled in ultra-deep carbonate reservoirs in Tazhong area, Tarim Basin

Wang Ping, Pan Wenqing, Li Shiyin, Guan Baozhu, Xiong Chang, Chen Lei   

  1. Research Institute of Petroleum Exploration and Development, PetroChina Tarim Oilfield Company
  • Received:2018-01-10 Revised:2018-11-20 Online:2019-01-15 Published:2019-01-02
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Abstract: As an ultra-deep (5,000-7000 m), complex and large-scale carbonate oil and gas field, Tazhong-Ⅰ condensate gas field had heterogeneous reservoirs and difficulties in keep stable gas production because of long well completion period and low drilling success rate, which were caused by long horizontal sections and difficulties in identifying vertical target layers. Previous design of the wellbore trajectory of a horizontal well drilled in carbonate reservoirs only considered the principal stress, but not the comprehensive characteristics of geostress, so it could not ensure that the horizontal wellbore was drilled in good reservoir zones, accordingly it was hard to design a path favorable for wellbore stability. In this study, based on reservoir development law and geostress characteristics, three optimization techniques including comprehensive evaluation of reservoir drill-in rate, prediction of reservoir top stress field and pre & post-stack fracture prediction were proposed for optimizing horizontal well trajectory. Application of these three technologies has significantly increased the drill-in rate to an average of 46.5%, and the drilling success rate to over 85% in horizontal well development. This promoted the effective development of the Tazhong-Ⅰ gas field, and provided basis and support to the optimization design of horizontal wellbore trajectory for developing carbonate reservoirs in the Tazhong-Ⅰ gas field and other similar carbonate oil and gas fields.

 

Key words: Tarim Basin, Tazhong area, carbonate reservoir, optimization of horizontal well trajectory, fracture prediction

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