An Experimental Technique to Quantify Jet Penetration Efficiency

MENAPS 16-04

AUTHORS: Dr Dennis Baum – Lawrence Livermore National Laboratory, Mark S Brinsden - Shell

NOV 13TH, 2016

MUSCAT, OMAN

Dynamic Evaluation of Perforator Performance

Background to the Testing of Perforator Performance

Design and execution of experimental technique to measure jet erosion in drilling mud.

Application of experimental technique to perforator charge performance

• A blowout scenario occurred in the Gulf of Mexico event in 2010

• Looking for additional safety measures, Shell started work on designing an Emergency Severance Tool (EST)

• An array of linear shaped charges was proposed to sever the 9.5” x 3” drill collar located inside the 21” OD marine riser

• The charges had to penetrate successive layers of steel and up to 240mm of drilling mud (density ~ 2g/cc)

Subsea drilling practices present high consequence operational challenges

Blowout preventer

EST to sever drill collar

The major design unknown was jet erosion in drilling mud

• The question to be addressed was whether ALE3D simulations accounted for the necessary physics to predict jet erosion in drilling mud

• We assumed the physics was independent of the conical vs. linear configuration of a jet

• The experimental plan was to fire three charges simultaneously and observe jet tip propagation after emerging from air, 60mm and 120mm of mud

• Because the conical charge tip speed is much greater than the linear charges, a 76mm steel stripper plate was used to reduce the tip speed from 9.2km/s to less than 6km/s

A well-characterized 65mm conical shaped charge was selected for the erosion study

Dimensional layout of experiment as used in simulations

Schematic representation of vertical charge array for erosion test

Conical TestCharges (3)

Experimental setup showing aircraft foam for charge support and mud tanks

Conical charges Witness plates

Simulated tip position for jet passing through 120mm mud tank

5.4km/s 9.2km/s

120mm mud tank

Conical charge

Jet radiographs before (56μs) and after (110μs) mud penetration

Charge Radiograph

Time(μs)

Position (mm) Erosion (mm)

Sim. Actual % diff. Sim. Actual % diff.

B1, 2, 3 Beforemud

56 196.15 201.38 -2.59 - - -

B1 No mud 110 486.88 494.06 -1.45 - - -

B2 60mm mud 110 453.60 459.71 -1.33 33.3 34.4 -3.3

B3 120mm mud

110 417.51 425.73 -1.93 69.4 68.3 1.5

Test data show jet erosion simulations within 1.1mm (~3%) of data

Conclusion: Modeling drilling mud as water with a density of 2g/cm3 is adequate

for accurate simulation of shaped charge jet erosion in velocity regime of interest to

this problem

• Replace test charges with perforator charges of interest

• Replace drilling mud with incremental thicknesses of target materials of interest (concrete or geologic material)

• Use the same three charge array to characterize penetration of individual sections of a perforator jet

• The first array measures jet erosion in leading half of jet

• The second array measures jet erosion in trailing jet

Application of experimental technique to perforator charge performance

Measure length of jet consumed in penetrating incremental thicknesses of target material

• Determine total depth of penetration (P) of jet into target material of interest

• Array 1 (3 charges) evaluates jet erosion in leading half of jet with radiographs before and after penetrating material thicknesses of 0, 0.25P, and 0.5P

• Array 2 (3 charges) evaluates jet erosion in trailing half of jet with radiographs before and after penetrating material thicknesses of 0.5P, 0.7P, and 0.9P.

• Note the stripper will be target material of thickness 0.5P or equivalent, which will remove the leading half of the jet.

• Define penetration efficiency, keff = target thickness/jet erosion

Design of array to evaluate perforation efficiency as a function of penetration depth

Schematic representation of vertical array for perforator erosion tests

Perforator charges (3)

Stripper when required

0.25P target

0.5P target

Reference target

Witness plates for residual penetration

Experimental setup showing aircraft foam for charge support, incremental targets, and radiograph views

Perforator

chargesWitness plates

0.25P

0.5P

Charge Target X-ray time Jet tip position (mm) Erosion (mm) Penetrationefficiency

A1 0 t1 z1 reference -

A2 0.25P t1 z2 z2-z1 0.25P/z2-z1

A3 0.5P t1 z3 z3-z1 0.5P/z3-z1

B1 0.5P t2 z4 reference -

B2 0.7P t2 z5 z5—z4 0.7P/z5-z4

B3 0.9P t2 z6 z6-z4 0.9P/z6-z4

Data table for determining penetration efficiency of perforator jets

Penetration efficiency = Target thickness/jet erosion.

Higher number means higher rate of penetration by jet.

Summary

• An experimental technique is presented for evaluating penetration efficiency of perforator jets

• Penetration efficiency is measured as a function of penetration depth

• Incremental penetration efficiency data can provide a basis for improved charge designs

An Experimental Technique to Quantify Jet Penetration Efficiency

QUESTIONS? THANK YOU!

MENAPS 16-05

MUSCAT, OMAN