A Study On The Hydraulic Fracturing Pressure Behavior Well-testing Analysis And Stimulation Effect Improvement Method

Hydraulic fracturing is a generally applied technique for enhancing production of wells for low permeability formation in exploration and exploitation. The vertical fractures made can alter flow mode in reservoir along well bores, increase drain area, advance the sweeping oil efficiency, and finally work on production and recovery. The effect analysis of hydraulic fracturing and its approach for increasing production are the key factors for guaranteeing hydraulic fracturing success ratio. A comprehensive study has been made to a comparatively integrated system of vertical fractures' theory and means based on establishment of basic mathematic models. The transient flow of the vertically fractured well has been discussed particularly and derived at Laplace domain about finite & uniform flow & infinite-conductivity vertical fracture considering wall damage and has been numerical solved applying boundary element means. The conductivity of vertical fractured well is very difficult to describe in math methods because of the conductivity varied at different place. The linear, exponential, logistical forms about varying conductivity have been discussed and solved. In view of the main factors of skin damage, near wellbore formation pollution and cold damage which affect fracturing effects, some creative stimulation methods are studied; meanwhile, the encapsulated breaker which can be added excessively and used for improving the breaking effects of the fracturing fluid and the formulation and composition of the encapsulated material are experimentally studied; an integrated technology of fracturing-gas lift-production is investigated and rapid and continuous flowback for the fracturing fluid is realized by use of the multistage high-pressure gas lift valve to improve the flowback rate of the fracturing fluid; he formulation and composition of VES-80 clean fracturing fluid with light-molecule surfactant as the viscosifying agent are developed and its performance is evaluated and tested to reduce the secondary pollution of the fracturing fluid significantly. Hydraulic fracturing pressure behavior well-testing analysis and stimulation effects improvement method developed in the paper have been applied in Tuo32 of Liaohe Oilfield and good effects have been achieved. It is expected that though the study of the paper, the theory and method about the vertical fracture could be improved to a higher level. Thereby, it could present better basis of the theory and method of application for the hydraulic fractured field.