Journal of Southwest Petroleum University(Science & Technology Edition) ›› 2024, Vol. 46 ›› Issue (1): 97-104.DOI: 10.11885/j.issn.1674-5086.2021.08.31.01

• OIL AND GAS ENGINEERING • Previous Articles     Next Articles

Segmented Water Control Strategy for Small-angle Swallowtail Sidetracked Horizontal Wells in the Same Layer

TANG Xiaoxu1, PEI Bailin2, ZHAO Wei2   

  1. 1. Tianjin Branch, CNOOC China Limited, Binhai New Area, Tianjin 300452, China;
    2. Anton Bailin Petroleum Technology (Beijing) Co. Ltd., Changping, Beijing 102200, China
  • Received:2021-08-31 Published:2024-02-01

Abstract: In Bohai Oilfield, the number of wells with high water cut, low production and low efficiency has gradually increased, and the production of some blocks has declined rapidly. Sidetracking in the same layer with segmented water control completion was an effective method to tackle high water cut, low production and inefficient wells. Whereas, the effect of water control was not significant for small-angle swallowtail sidetracked horizontal wells with segmented water control technique. The theoretical model was build to find the reason why the effect of water control failed and it was found out that the original wellbore of this type of wells played the main role in this failure. After considering factors such as feasibility and economics, adjusted on existing drilling and completion method, a comprehensive drilling and completion improvement strategy featuring horizontal section extension and piping optimization for completion string was proposed, and the effectiveness of this strategy was verified in the field. The water control effect was much better than expected, no water production has been witnessed 164 d after commissioning, and the cumulative oil production in water free was as high as 15 000 m3. The target well adopting the new strategy achieved significant water control effect, while the cost of single well construction increased by only 8.8%. It provides ideas and technical reserves for the follow-up treatment of similar low production and low efficiency wells.

Key words: low production and low efficiency well, sidetracked technique in the same layer, segmented water control technique, horizontal well water control, drilling and completion strategy

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