摘要
Gulong shale has abundant oil resources with low-porosity and low-permeability reservoir characteristics,and effectivedevelopment has been achieved using horizontal well volume fracturing in singlewell network deployment.Compared with tight oil,the terrestrial pure shale oil reservoir has more complex geological characteristics with developed shale joints and high clay content,which have a great impact on both hydraulic fracturing and production effects.Therefore,it is important for well spacing to be specifically designed for optimal single-wellproduction and reservoir recovery rates.Taking the No.1 Test Area of Gulong shale oil as an example,the inter-well interference intensity was evaluated by monitoring fracture construction pressure interference,tracer fugitive flow,and downhole microseismic phenomena at different well spacing.Using the unconventional reservoir production instability analysis method,the influence of well spacing on the length of effective fracture with proppant was examined,and the lower limit of 400 m well spacing was determined.Based on the geological and production evaluation parameters of the test area,a multi-well numerical model of the reservoir was established based on the differences in effective fracture length at different well spacing,and reasonable well spacing was demonstrated by considering the estimated ultimate recovery(EUR)of a single-well and block recovery rate.The simulation shows that the effect of well spacing on the development effect of Gulong terrestrial pure shale oil is different from that of tight oil and shale gas.By increasing the well spacing,the single-well EUR of shale oil increases significantly;the recovery first increases and then decreases,and the variation is small.Based on the current fracturing pattern and scale in the test area of Gulong shale oil,the well spacing of 300 m can be optimized to 500—550 m,the single-well EUR can be more than doubled,and the recovery can be increased by about 20%.
基金
financial support by the PetroChina Company Limited Technological Project(grant no.2023zz0404).
