Rostehnadzor approved methodologies CC-05 and MBM-08 are used for shaped charges perforating efficiency testing.
The main goal of testing is to define actual characteristics of tested items.
Testing methodology, testing volume, selection rules, items testing preparation, target selection and number of firing is set according to testing program and methodology.
Minimal quantity of testing items is 3.
CC-05 methodology testing
According to this methodology, shaped charges testing is conducted with metal target, consisting of the 10 mm steel plate (imitation of casing tube), which is placed in the upper target and packet part, which consists of metal plates (for DP charges plate material is St. 20, for BH charges plate material is AD31). Plates quantity is defined in order to reach total packet height on 50-75 mm higher than announced perforation depth.
Plates are placed into the special holding device, which allows fixing plates without any gap between them.
Charges are placed on the target to imitate perforator charge location, depending of the charge type: the bushing filled with water (imitating water gap) is placed on the upper steel plate, imitating the casing tube; then the 50x50 mm steel plate is placed on the bushing (St. 20 material) to imitate the perforator wall on which the focus-bushing is placed. The plate thickness and the focus height vary depending on the applied perforator type. The shaped charge is placed on the focus-bushing.
After shooting, the target is disassembled and shaped charge perforation depth is defined by counting of perforated plates and measuring the channel depth of remained not fully perforated plates with sliding caliper.
Then internal sizes of every incoming and outgoing hole in 10 mm plate on the short and long ellipse axes are measured with sliding caliper and incoming diameter is calculated as arithmetical mean of measured dimensions. Measurements are made from the charge disposition side.
Testing results are written down to special log journal and the special statement is drawn up.
MBM-08 methodology testing
Shaped charges tests are conducted using the quality control concrete target MKKB.
MKKB target is chosen to reach its total dimensions (length) 50 mm more than announced shaped charge perforation depth.
More than 28 days old concrete targets are used for testing. 6 standard concrete cubes from each party are analyzed to determine the target strength. Not earlier than 24 hours before or not later than 24 hours after charges testing these concrete cubes are tested on compression strength. Average compression strength has to be more than 35 MPa and less than 60 MPa. The strength is determined by pressing the tested items with special press or ultrasonic device UKS-MG4S.
Charges are tested by firing according to the scheme imitating perforator charge location, depending on the charge type: on the upper side of the MKKB target the 80x80x10 mm metal (St. 20) plate imitating the casing pipe is placed; then the bushing filled with water (imitating water gap) is placed on the steel plate; then the 50x50 mm steel plate is placed on the bushing (St. 20 material) to imitate the perforator wall on which the focus-bushing is placed. The plate thickness and the focus height vary, depending on the used perforator type. The shaped charge is placed on the focus-bushing.
After firing, the target is accurately split along the perforated channel, the channel is cleared with a brush and the distance between the lower target end and the channel end is measured. The measured actual perforation depth is normalized in case of using the target with more than 35 MPa compression strength. Normalized perforation depth is defined as 5% depth increase with every 7MPa strength increase.
Then internal sizes of every incoming and outgoing hole in 10 mm plate on the short and long ellipse axes are measured with sliding caliper and incoming diameter is calculated as arithmetical mean of measured dimensions. Measurements are made from the charge disposition side.
Testing results are recorder at special log, then the special statement is drawn up.
The MBM-08 testing results are used to define the metal (CC-05) to concrete perforation recount coefficient.