Hydraulic Fracture Conductivity Evaluation And Research For Channel Fracturing In The East China Sea Gas Field

Channel fracturing is a new hydraulic fracturing technology that uses pulsed sanding process to make the proppant non-uniformly laid in the fracture,form infinite diversion channels and significantly improve the fracture eonduetivity.The fracture eonductivity is an important parameter which greatly affectes the effect of fracturing construction.In order to study the influence of various influencing factors on the fracture conductivity of channel fracturing,this paper combined the special reservoir conditions of the China East Sea gas field,the technical adaptability of channel fracturing was studied,the multi-size combined sanding form and physical model of channel fracturing crack were designed,the experimental evaluation of indoor gas-measuring fracture conductivity was carried out,and the fluid flow in the crack of channel fracturing was simulated by using fluid simulation software,to comprehensively evaluate the influencing factors of the fracture conductivity,which can provide the basis for the design and optimization of the fracturing process parameters of the channel fracturing of the East China Sea gas field.The main target tasks should be accomplished in this paper are as follows:(1)The technical adaptability of channel fracturing of the East Sea gas field was studied,technical principles and comparative study of the advantages and disadvantages were studied to reflect advantages of channel fracturing technique.According to the rock mechanics and in-situ stress conditions of the East China Sea gas field,the technical adaptability was analyzed.(2)Considering the actual channel fracturing process and the sand morphological characteristics of the sand,based on the conventional single-size proppant block sanding method of channel fracturing,multi-size proppant block sanding methods were designed and physical models was established,which can improved the limitations of the current channel fracturing sanding experiments.(3)The indoor gas-measuring fracture conductivity experiments were accomplished by using the proppant crack deflector,considering the effects of proppant type,closure pressure,sanding concentration,fiber concentration,proppant group shape and arrangement.The experimental results can provide a reliable basis for the optimization of sand concentration,fiber concentration and proppant placement,and gas reservoir fracturing design and construction.(4)According to the sand-sanding pattern of the channel fracturing crack designed by the laboratory test,the geometric model and the mesh model for the theoretical simulation of the fracture conductivity were established,then used fluent software to simulate natural gas flow in the fractures of the channel fracturing,and the gas conductivity was calculated from the simulation datas.Based on the coupling of the test results,the influence of various influencing factors on the fracture conductivity of channel fracturing were studied.(5)Based on indoor gas-measuring fracture conductivity experiment and software simulation study,the influence of proppant type,proppant sand concentration,fiber concentration,sanding method and other factors on the fracture conductivity were comprehensively analyzed,and the same conclusions were gotten.Based on the previous research on theories channel fracturing and the improvement of laboratory tests,this paper further combined the indoor gas-measuring fracture conductivity experiment with software simulation study,and comprehensively evaluated the influencing factors of fracture conductivity of channel fracturing.This paper can provide theoretical support for the optimization of parameters and optimization design for channel fracturing,also has guiding significances for on-site construction.