Perforation Crushed Zone Characteristics in a Subsurface Sandstone

2018 ◽  
Author(s):  
G. G. Craddock ◽  
John Smith ◽  
Dennis Haggerty
Keyword(s):  
Crushed Zone

Characterization of the Jet Perforation Crushed Zone by SEM and Image Analysis

1994 ◽  
Vol 9 (02) ◽  
pp. 135-139 ◽  
Author(s):  
M. Asadi ◽  
F.W. Preston
Keyword(s):  
Image Analysis ◽  
Crushed Zone

scholarly journals The Effects of Confining Stress on Rock Fragmentation by TBM Disc Cutters

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
S. F. Zhai ◽  
S. H. Cao ◽  
M. Gao ◽  
Y. Feng
Keyword(s):  
Confining Pressure ◽  
Numerical Results ◽  
Rock Fragmentation ◽  
Disc Cutter ◽  
Confining Stress ◽  
Disc Cutters ◽  
Initiation And Propagation ◽  
Maximum Angle ◽  
Indentation Tests ◽  
Crushed Zone

In this paper, General Particle Dynamics (GPD3D) is developed to simulate rock fragmentation by TBM disc cutters under different confining stress. The processes of rock fragmentation without confining pressure by one disc cutter and two disc cutters are investigated using GPD3D. The crushed zone, initiation and propagation of cracks, and the chipping of rocks obtained from the proposed method are in good agreement with those obtained from the previous experimental and numerical results. The effects of different confining pressure on rock fragmentation are investigated using GPD3D. It is found that the crack initiation forces significantly increase as the confining stress increases, while the maximum angle of cracks decreases as the confining stress increases. The numerical results obtained from the proposed method agree well with those in previous indentation tests. Moreover, the effects of equivalent confining stress on rock fragmentation are studied using GPD3D, and it is found that rock fragmentation becomes easier when the equivalent confining stress is equal to 15MPa.

An Improved Model for Estimating Flow Impairment by Perforation Damage

SPE Journal ◽  
2007 ◽  
Vol 12 (02) ◽  
pp. 235-244 ◽  
Author(s):  
Jacques Hagoort
Keyword(s):  
Flow Model ◽  
Radial Flow ◽  
Flow Coefficient ◽  
Darcy Flow ◽  
High Rate ◽  
Gas Wells ◽  
Aspect Ratios ◽  
Damaged Zone ◽  
Crushed Zone ◽  
Inflow Performance

Summary In this work, we present two simple formulas for the skin of a perforated well caused by perforation damage: one for the reduction in permeability, and one for the increase in non-Darcy flow coefficient (beta factor). They are based on the inflow performance of a single perforation obtained by means of a prolate-spheroidal flow model. This model rigorously accounts for the flow convergence toward a perforation, especially near the tip of the perforation. It provides a more realistic description of the inflow than a radial flow model, the basis for the existing skin formulas proposed by McLeod (1983). In the case of perforations with a large aspect ratio and a thin damaged zone, the formula for the skin due to permeability reduction reduces to McLeod's formula. The formula for the non-Darcy skin yields a significantly larger skin than predicted by the radial flow model, up to a factor 1.4 for large aspect ratios. Finally, we demonstrate that perforated wells are much more liable to non-Darcy flow than openhole wells, in particular if the perforations are severely damaged. Introduction Oil and gas wells are commonly completed with production casing cemented in place and perforated to enable fluids to enter the wellbore. The perforations are created by perforating guns and have the form of straight elongated and circular holes that stick into the formation perpendicular to the wall of the wellbore. The perforation holes are surrounded by a damaged zone of crushed and compacted rock. Typically, a perforation has a diameter of approximately a quarter-in., a length of a few up to more than a dozen inches and a crushed zone thickness of up to 1 in. It has been long recognized that perforation damage may drastically impair the flow efficiency of a perforated well. Not only is this caused by a lower permeability in the crushed zone, but also by a higher inertial resistance coefficient (non-Darcy flow coefficient), which is particularly important for prolific, high-rate gas wells. Customarily, the inflow performance of a perforated well is described by the radial openhole inflow formula, in which the effect of the perforations (e.g. geometry, shot density, phasing, and perforation damage) is included as a pseudo skin (Bell et al. 1995). The current model for estimating the Darcy and non-Darcy skins due to perforation damage was proposed by McLeod(1983). In this model the perforation is represented by an open circular cylinder surrounded by a concentric crushed zone of reduced permeability and enhanced non-Darcy flow coefficient, and the inflow into this cylinder is assumed to be radial, perpendicular to its axis.

Liners with Bulk Metallic Glass/High Entropy Alloy, Degradable in Formation Fluids for a Skin Free, Clear, Perforating Tunnel, Enabling Enhanced Reservoir Connectivity

2021 ◽  
Author(s):  
Ting Chen Roy ◽  
Kamel Bennaceur ◽  
Daniel Markel ◽  
Leonard Harp ◽  
Casey Harrison ◽  
...  
Keyword(s):  
Common Knowledge ◽  
Shaped Charge ◽  
High Entropy Alloy ◽  
Fracture Conductivity ◽  
High Entropy ◽  
Expected Time ◽  
Intergranular Films ◽  
Crushed Zone ◽  
Eventual Collapse ◽  
Reservoir Connectivity

Abstract A shaped charge for wellbore perforation includes a solid metal or powder liner pressed onto a case, sandwiching high explosives which may have varying thermal stability, dictated by the expected time of exposure and bottom hole temperature (BHT). It is common knowledge that post detonation, the liner-jet punctures the gun body and casing, continuing forward to perforate the formation until its eventual collapse. The jet debris is deposited on the crushed zone forming an impermeable skin and a slug at the end of the perforation-tunnel. This reduces fracture conductivity, and thus, production. Here we present a game changing innovation, the development of a shaped charge with a novel responsive liner. The jet created from our novel degradable liner, post detonation punctures the casing and progress to penetrate the formation until an eventual collapse. However, this system is designed so that, during detonation, a water disintegrable reaction product, bulk metallic glasses (BMG) and/or high entropy alloys (HEA), are formed. These degradable BMG/HEA or complexions decorate the grain boundaries and domain interfaces of the impermeable skin lining the crushed zone of the perforation tunnel as amorphous intergranular films (AIFs) and plug at end of the pathway. Interacting with flowback fluids the BMG/HEA promotes grain dropping, disintegrating the liner and carrot leaving behind a clean perforation tunnel, improving fracture conductivity thus enhanced productivity. In addition, a clear perf tunnel has zero skin value. As such, compared to a coated tunnel with gun and charge debris, it needs little or no acid to clean-up. This results in a demarked reduction of formation breakdown pressures with improved economics for the client. Last but not least this leads to cost reduction of authorized field expenditure (AFE) to support optimized performance of completion design allowing for increased production. CLEAR shaped charges have been qualified to customer specifications in field conditions and are ready to be commercialized. An extension of this technology is being applied to design charges for "Big-Hole" perforations, for the Plug and Abandonment (P&A) market where an effective cement squeeze, anchoring a plug effectively seals the wellbore, preventing the leakage of residual hydrocarbon and associated contamination and emissions.

Flow around a rock perforation surrounded by crushed zone: Experiments vs. theory

2006 ◽  
Vol 50 (2) ◽  
pp. 102-114 ◽  
Author(s):  
M. Jamiolahmady ◽  
A. Danesh ◽  
M. Sohrabi ◽  
D.B. Duncan
Keyword(s):  
Crushed Zone
Sign in / Sign up

Export Citation Format

Share Document