Analysis on the Influence of Perforation and Reservoir Parameters on the Propagation Law of Induced Fractures
As the depth and difficulty of oil and gas exploration and production increases,fracturing is usual-ly needed to be conducted to improve productivity.Perforation and reservoir parameters are the main factors affect-ing the fracturing effect.Benchmarking against the classic true triaxial fracturing simulation test,an extended finite element fracturing model was built.The applicability of the extended finite element model in analyzing the fractu-ring effect was verified and improved.Finally,the influence of perforation and reservoir parameters on the propaga-tion law of induced fractures was analyzed.The research results show that when the perforation angle changes from 0° to 75°,the fracture initiation pressure first decreases and then increases.When the perforation angle is 30°,the fracture initiation pressure is the minimum,i.e.,36 MPa;75°,the maximum,i.e.,41.9 MPa,with a variation amplitude of 16.4%.The fracture width decreases from 0.013 8 m to 0.003 3 m,with a decrease ampli-tude of 76.1%.The fracture length first decreases and then increases,and is the minimum,i.e.,23.54 m at 45° perforation angle,and the maximum,i.e.,25.45 m at 0° perforation angle.When the perforation depth changes from 0.6 m to 1.8 m,the fracture initiation pressure decreases from 47.7 MPa to 39.79 MPa,with a var-iation amplitude of 24.1%;and the variation amplitude of fracture width is less than 4%.When the horizontal ground stress difference changes from 0 MPa to 7 MPa,the fracture initiation pressure increases from 32.97 MPa to 41.04 MPa,an increase of 19.7%;the fracture width decreases from 0.013 12 m to 0.006 86 m,a decrease of 47.7%;the fracture length decreases from 24.5 m to 23.8 m,a decrease of 2.9%.When the elastic modulus changes from 10 GPa to 16 GPa,the fracture initiation pressure changes by 0.43%,and the fracture width and length increase by 25.4%and 35%,respectively.When the tensile strength changes from 1 MPa to 6 MPa,the fracture initiation pressure increases from 37.58 MPa to 48.22 MPa,an increase of 28.3%,the fracture width in-creases by 27%,and the fracture length decreases by 21%.When the elastic modulus changes from 10 GPa to 16 GPa,the fracture width decreases by 17.3%,and the fracture length increases by 23.1%.The research results provide reference for the optimization of fracturing parameters.
fracturingperforation and reservoir parametersboundary extensionfracture initiation pres-surefracture widthfracture length
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