Study On Fracturing Technology Of Micro-acidification And Sand In Bottom Water Reservoir

The key to effectively fracturing low-permeability bottom-water reservoirs is to control the vertical extension height of fractures and prevent them from extending downward to the bottom water layer.Therefore,solving the issue of controlling the height of fractures in the exploitation of bottom-water reservoirs can promote the development of on-site fracturing technology in bottom-water reservoirs of JY oilfield and improve the economic benefits of the oilfield.In this paper,the following research work was carried out centering on the development of low-concentration strong acid fracturing fluid system and sand fracturing technology,which are suitable for bottom-water reservoir:（1）Geological study and the sensitivity of reservoir study were carried out on bottom-water reservoir in JY chang2 block.（2）A set of low-concentration strong acid fracturing fluid system for bottom-water reservoir characteristics of JY chang2 block was studied through laboratory experiments,the proppant was also optimized;（3）FracproPT fracturing simulation is used to optimize fracturing modes,fracturing scale,construction parameters,etc.In the end,the optimal selection experiment in the laboratory determined that the fracturing liquid system with low concentration and strong acid was formulated as follows:water+0.3%CQ-2 carboxymethyl hydroxypropion gum+5%hydrochloric acid+0.3%HPAM+4%KCl+0.05%organosilicon+0.02%1631;The crosslinking agent was YBJ-3 organic zirconium.The cross-linking ratio was 100:1.8.ceramsite sand was selected as proppant for fracturing.Then used FracproPT determined the chang2 reservoir,under the different reservoir conditions,of crack length in the range of 50m to 80m,dimensionless flow conductivity optimization results showed that the F_CDD should be between 1.6⁹,perforation position should be located at the top of the reservoir,reservoir perforation azimuth should be between0°and 30°,perforation aperture is 1cm,perforating density should be 16 holes/m,perforation degree according to different reservoir thickness should be between 15%⁴5%;the optimal displacement should be 0.8m³/min¹.2m³/min,the sand content should be 5m³¹5m³,the sand strength should be 1.0m³/m¹.22m³/m,and the amount of sand-carrying fluid should be 23m³⁶7m³.Under the condition of reservoir,the optimized preflush fluid volume is about 25%,and the optimized optimal displacement fluid volume is 5.7m³⁵.9m³.Finally through the SY-1,SY-2 fracture testing wells construction curves and fracture results analysis prove that the chang2 reservoir bottom-water reservoir development of low concentration acid fracturing fluid system and optimized process parameters of sand fracturing technology,can better adapt to the chang2 reservoir JY chang2 block.