The Experiment Study Of Temporary Blocking Diversion Fracturing In The Tight Sandstone

Diversion fracturing is a new fracturing technique that use chemical or solid particles and other materials as a temporary plugging agent,temporarily plugging the old fracture,making the fluid turn,creating a new fracture.It can fully control the one-way fracture propagation,achieve multi-level short-term temporary plugging,and change the fracture direction,make a new complex fracture network,the fully intercommunicate the production are to maximum level,improve the reservoir capacity.The plugging performance of the temporary plugging agent and the placement method determine the effect of the fracture turning and fracturing treatment.At present,fracturing curve and seismic monitoring are usually used to explain whether or not the fracture is turned.In this paper,based on relevant theoretical system,a experiment device simulating the underground reservoir fracture is developed for performance evaluation of temporary plugging agent,and some fiber temporary plugging agent and a water-soluble particle temporary plugging agent generally used by the field are chose to study.The experimental results show that the fiber dispersion,degradation,sand carrying properties have a very important impact on the temporary plugging performance of the fiber,and the higher the pressure,the more easily the formation of tight temporary blocking layer,the better the plugging performance.And a new type of temporary plugging agent with better temporary plugging performance is proposed.The chosen temporary plugging agent with the good performance of the plugging are used to study the fracture diversion.According to the relevant theory,simulating field fracturing process,another device is developed for the fracture diversion experiment study,the effect of the different fiber concentrations and different water soluble temporary plugging agent concentration on fracture diversion is studied.the concentration range of temporary plugging agent is optimized.The experimental results show that the fracture pressure of the new fracture is 1.1 times that of the original fracture,and the strength of the temporary plugging agent to achieve the crack diversion should be 1.2-2 times of the horizontal stress difference.At the same time,the test results are verified by the full scale real three axis rock mechanics test system.The experimental results are applied to the fracturing treatment of a well in the oil field.The research results of this paper will help us further grasp the diversion fracturing technology and improve the reservoir fracturing performance.