Exploration and practice of ultra-low permeability reservoir development of Dagu 67 block

Dagu 67 block of Dawangzhuang oilfield is a fault block reservoir with deep depth and ultra - low permeability of 9.6×10~(-3)μm~2,and the main oil-bearing series are Shihezi formation of Permian.Starting from formation testing,the block has experienced three development stages;natural recovery phase,water flooding phase and infilling adjustment, with the characteristics of big difference of initial productivity, quick production decline,poor physucal properties and poor capacity of water absorption.Therefore,through many years of development exploration,the development techniques such as optimized well spacing and well pattern,intensify water flooding,fracturing reform,and reservoir protection, which can effectively enhance the development effect of the ultra-low permeability reservoir.At present,the daily oil production of single well is 5.3 t,with water cut of 28.1%,recovery of 8.74%and the oil producing rate of 1. 27%.