The Pressure Drop Model of Liquid Flow with Wall Mass Transfer in Horizontal Wellbore with Perforated Completion

The fluids in horizontal wells can exhibit complicated flow behaviors with wall mass transfer, partly due to the interaction between the main flow and the radial influx along the wellbore and the completion parameters used. This paper presents a novel regression model established based on the experiment data retrieved from the available literatures to determine the apparent friction factor for a single phase wellbore flow. The proposed model has the potential to be readily applicable to different perforation parameters, such as shot phasing and shot density. Compared with other models in the same practical example which is offered by Ouyang et al., the model of this paper to calculate the wellbore pressure is applicable and reasonable. This new model can be easily incorporated into reservoir simulators or analytical reservoir and horizontal wellbore inflow coupling models.

The Analysis of the Influence of Perforating Parameters on the Strength Security of Perforation String

Perforating parameters, such as charge density, charge quantity and shooting density, are the important factors that affect the strength security of perforation string. Finding out the relationship between this two and understanding the regularity has the guiding significance to avoid the perforating accidents. Based on the research about the strength security of perforation string at the moment of perforating, taking a perforated completion gas well as an example, by changing the perforating parameters and conducting the contrastive analysis and research, then gets the regularity understanding about the influence of the perforating parameters on the strength security of perforation string:When the charge density is more than 1.9g/m3, the amplification of peak pressure will slow down ,and the influence of charge density will decrease; When the charge quantity is more than 40 gram, the amplification of the peak pressure on the packer and the peak stress of tubing will slow down ,and the influence of charge quantity will decrease; When the shooting density is more than 20 hole/m, the amplification of peak will slow down, and the influence of shooting density will decrease.

Enhancement of the Completion Efficiency of Perforation Tunnels in Petroleum Wells

The objective of perforating is to maximize well productivity by establishing good connectivity between the wellbore and formation. The conventional method of perforation — perforation by shooting (PS) — cannot achieve expected wellbore productivity due to a region of reduced permeability around the perforation tunnel. In this study, it has been established that permeability is decreased in the range of 30%–75% due to the implementation of the PS technique compared to the openhole completion. As a result, a new perforation technique — perforation by drilling (PD) — has been proposed in this paper. To simulate a perforated completion, cylindrical sand samples (0.0572 in OD) consolidated with cement with varying porosity were prepared. These samples were perforated (0.0136 m ED) by the PS, PD and Casting techniques. Perforations created by the Casting techniques are considered the ideal, openhole perforation tunnel. Fluid flow rates and differential pressure across the perforated samples were measured for three different types of samples using “Geotechnical Digital System” triaxial testing set-up. Fluid flow rates with changing differential pressure and finally pressure build-up data with time indicates the PD technique can achieve better wellbore productivity compared to the PS technique. Results indicate that at 100 kPa differential pressure the PS, PD and Casting techniques can achieve 0.20 mL/s, 0.65 mL/s and 1.00 mL/s fluid flow rates respectively across a sample.