Oil & Gas Geology ›› 2021, Vol. 42 ›› Issue (5): 1223-1233.doi: 10.11743/ogg20210519

• Methods and Technologies • Previous Articles     Next Articles

Producing reserve estimation and design optimization of rhomboid well pattern in anisotropic reservoirs of low permeability

Minfeng Chen1,2(), Ziyou Yang3, Lifeng Qin2, Shixiong Fu2, Jinxi Rong2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
    2. School of Petroleum Engineering, China University of Petroleum(Beijing), Beijing 102249, China
    3. Bohai Oilfield Research Institute of Tianjin Branch, CNOOC, Tianjin 300459, China
  • Received:2020-06-08 Online:2021-10-28 Published:2021-10-26

Abstract:

Determining a well array with reasonable spacing for flooding in rhomboid well pattern, is the key to achieving effective development of reserves and well emplacement for equilibrium displacement development in regular low-permeability anisotropic reservoirs.Based on the characteristics of low-permeability reservoirs, we establish a seepage equation considering the influence of threshold pressure gradient and permeability anisotropy.Classical seepage mechanics is applied to obtain an analytical solution for the seepage field distribution in flooding unit of the rhomboid inverted nine-point well pattern.In turn, a method for evaluating the producing reserve is proposed in line with the analysis of the lateral seepage velocity variation in the flooding unit, and the main factors influencing and rules of producing reserve variation in low-permeability anisotropic reservoirs at different conditions are obtained.At last, a calculation model for optimizing the rhomboid inverted nine-point well pattern is built with the ultimate optimization purpose of meeting "requirement on effective producing reserve range and maximum equilibrium displacement coefficient", and a simultaneous optimization for the best well array with reasonable spacing in this pattern is achieved.Case analysis shows that the rhomboid well pattern optimization design method for low-permeability anisotropic reservoirs can be applied to obtain the best well array with reasonable spacing in line with the actual conditions of the reservoir and the development requirements.The design in all, is of scientific basis to the effective development of reservoirs and optimal emplacement of well patterns.

Key words: effective reserve producing, equilibrium displacement, optimization design, anisotropy, rhomboid injection-production well pattern, low permeability reservoir, reservoir development

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