Hydraulic fracturing is a delicate process which offers great economic benefits. The process, however, needs to be carefully designed, executed and controlled in order to limit its environmental impact and optimise the oil recovery. Equipment specification, data collection and design process are critical factors for any hydraulic fracturing treatment success. This paper investigates tubing specifications selection and its effect on the results of hydraulic fracturing treatment in oil formations.
Simulations were carried out on well E 45 owned by National Oil Corporation (NOC) of Libya using two main tools - Pumping Diagnostic Analysis Toolkit (PDAT) and Halliburton proprietary software package (FracPro) for analyzing Mini-Frac pumping data. The initial modelling results using 3.5 inch tubing were compared with the experimental results obtained from the actual hydraulic fracturing tests carried out at E 45. The simulation results showed good agreement with the experiments, validating the model.
The model was then extended to explore alternate tubing diameters. This was implemented by introducing the relationship between the tub friction pressures and pumping rate (Friction Pressure vs. Pumping Rate) with the mentioned tube sizes. The results showed that in high stress rock formations, it is advantageous to minimize the pipe friction by using higher tubing grade (4.5 inches) and higher burst pressure. A bigger tubing inner diameter increases the allowable surface pumping rate and pressure.
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