Mathematical study of fracture face skin in hydraulic fractures

The results of hydraulic fracturing design and analysis were obviously mistaken by the former fracture face skin model.In order to reveal this skin effect more accurately,based on the classical theoretic models of perkins,kern and norgren(PKN) and khristianovic,geertsma and dekerk(KGD),a new mathematical model of fracture face skin with segmentation characteristic was established using fracture mechanics and fluid coupling method.Comparing the new model with the Cinco-Ley model through field data,the results show that the productivity of the Cinco-Ley model was influenced by only 5%,while that of the new model by 50%.This revealed the poor post-fracturing production with fracturing techniques that are regarded as most effective means by many designers.Using this new model,the influence of skin on productivity was reduced and made fracturing treatment more adaptable and scientific.Through field tests on 35 wells,the output was increased 1.5 times and the costs were dramatically cut by new model.