These works are performed in vertical, directional and horizontal wells. Bashneftegeofizika JSC attaches great importance to implementation of state-of-the-art technologies and occupational safety.
Bashneftegeofizika JSC has all requisite permitting documentation and licenses for blasting-perforation operations in the territory of the Russian Federation.
Types of borehole springing and blasting:
- Casing perforation with jet-type perforating on the logging wire.
- Casing perforation with jet-type perforating on the tubing string, including underbalanced, using packer systems.
- Thermal and gas chemical treatment of the formation to intensify inflow.
- Isolation of well sections with explosive packers and cement plugs.
Jet-type wireline-conveyed perforation
During perforation of producing intervals both wireline-conveyed and tubing-conveyed perforating guns are used. This allows for optimal conditions for the formation exposing, underbalanced perforation of a producing zone, including displacing the well to oil, acid composition, and flush liquid.
Perforation is performed using modern perforation charges with high penetrating force. Using high-penetration perforating systems during casing perforation allows for well flow rate significant increase.
A cycle of special activities is performed after perforation in order to clean up the bottom-hole by means of swabbing, injecting with simultaneous measurement of hydrodynamic characteristics. This enhances the efficiency of the bottom-hole clean up and allows for selection of an optimal mode of the well commercial production.
Jet-type tubing-conveyed perforation with a packer
General perforation diagram
Application of modern perforation charges allows for the well production rate increase after perforation by 40% on the average. The presented method allows for creating considerable underbalance, initiating a significant oil inflow, thereby contributing to rapid cleaning of the bottom-hole. In this case there is no unplanned destruction of the cement shell, and adjacent rocks are penetrated in the intended spot.
Description of works performance
- Assembly rig-up: perforating gun, packer, circulation valve, flush pipe.
- Assembly tripping in and referencing to the perforation interval.
- Packer setting and pressure testing.
- Well drawdown before perforation, creating underbalance during perforation.
- Perforating gun initiating.
- Bottom-hole clean up by swabbing.
- Recovery of at least 1 well volume, bringing the well to stable production.
Well killing in case of well outflow, blowout
- The circulation valve is opened with pressure exerted on the casing annulus.
- Pressure in tubing and casing annulus is equalized by circulation.
- The packer is released, assembly is tripped out.
Advantages and benefits
- forms perforation tunnels without shock impact on the well casing parts;
- makes large diameter holes with a clean edge;
- high selectability when entering thin-layer formations;
- ensures efficient entering thin formations.
Jet pipe cutters are designed for cutting tubing and casing strings, as well as drill pipes with externally upset ends in wells with hydrostatic pressure up to 80 MPa and temperature up to 150°С.
The main advantage of these cutters compared to conventional ones is mass of charge which is about one tenth of its conventional value, which reduces fugacity during severing.
- charge case can be used several times, which reduces the cost of each firing, and, therefore, the cost of bottom-hole treatment;
- the lowest emergency rate due to reduction of blasting loads on the casing string and the cement stone around it;
- at blasting-perforation jobs wells are much less contaminated, since all charge fragments and rock cuttings are accumulated in the lower powder chamber;
- the highest net utilization of propellant gas energy due to the ability to control powder charge burning process;
- the most successful stimulation of marginal well producers with inflow initiation due to the implosive effect.
TshT heat-resistant cartridge cutters are designed for severing drill pipes during drilling accidents elimination (TShT 25/28 – TShT 84/90) and for shooting cased wells and wells where the producing reservoir is not cased, in order to increase flow rate and their injectivity (TShT 35/40 – TShT 84/90). They are used in wells filled with flush liquid at hydrostatic pressure of 100 MPa and temperature up to 160°С.
The cutters are tripped in on a single-core armoured wire.
Characteristics of applied cutter and pipe cutters
Explosive packers are designed for setting isolating plugs in the well intervals with casing string, creating a support for cement plugs setting, etc.