Investigation of a novel perforation technique in petroleum wells - perforation by drilling

Rahman M. A., Mustafiz S., Biazar J., Koksal M., Islam M. R.

JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS, vol.344, no.5, pp.777-789, 2007 (SCI-Expanded) identifier identifier


The objective of perforating the petroleum wells is to maximize well productivity. A good connectivity between the wellbore and formation can lead up to achieve that goal. However, the conventional method of perforation, which basically involves the use of explosive charges, rarely meets the expected well productivity. It is mainly because of the formation of a region of reduced permeability around the perforation tunnel. To offset such and several other shortcomings of present practices, a new technique is required, the highlight of this paper. Described as the 'perforation by drilling' (PD), this new technique is examined and compared for its performance with that of another technique, 'Perforation by Shooting' (PS). For this, the experimental and numerical results of the PS technique on cylindrical sand samples of varying amounts of strength and porosity are studied. Moreover, in order to achieve a so-called 'perfect perforation', results are compared with the 'Casting technique'. Three different samples were selected for the measurement of fluid flow rate and differential pressure across the perforation using a 'geotechnical digital system' (GDS., which is a triaxial testing device. Profiles such as fluid flow rate with a change in differential pressure and pressure build-up data with time, signify that the PD technique can achieve maximum wellbore productivity when compared to the PS technique. Results also indicate that at a 100 kPa differential pressure, the PS, PD and Casting techniques can achieve 0.20, 0.65 and 1.00 mL/s fluid flow rates respectively across a sample. The paper also implements a I-D time dependent porous media flow model to simulate flow across the perforated cylindrical samples created by the PS, PD and Casting techniques. Results show a good consistency between the experimental and numerical approaches. (c) 2006 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.