Sigra has a long involvement with drilling in many forms throughout its existence. This comes from having to work with whatever is available wherever that may be to the development of drilling systems. This range of involvement includes:
- Site investigation by conventional coring
- Site investigation by wireline coring
- Anchor hole drilling using down the hole hammers
- Horizontal drain emplacement using Odex and Simcas systems
- The drilling of dewatering wells for excavations
- The drilling of bored piers
- The use of twin drill string hammers to drill highly fractured rock.
- The manufacture and deployment of managed pressure drilling equipment for drilling from below the water table from diaphragm walls and tunnels.
- The use of long directional coring for tunnel exploration.
- The use of down hole motor directional drilling for cable emplacement.
- Exploration drilling using HQ wireline coring – this is the system with which most of Sigra’s tools to measure stress and permeability operate. We know this system very well.
- Directional drilling from surface. Sigra’s managing director, Ian Gray, introduced the first surface to in-seam drilling operation within Australia for the purpose of gas drainage of coal seams. This has gone on to be a very important method for gas and water drainage and also for exploration.
- Directional drilling from underground. Sigra have worked on numbers of improvements to drilling underground. These include a full suite of drilling software, part of which is a torque and drag model to enable the prediction of the the mechanical behaviour of the drill string in a tortuous hole. Sigra have worked on the development of drill rods suitable for directional drilling. Recently Sigra have also developed a rotary steering system for underground drilling to reduce problems with cuttings clearance associated with the use of downhole motors.
- The development of managed pressure drilling systems to enable drilling from underground in safety.
- The development and manufacture of well control systems for coring. Some 70 of these have been supplied world-wide.
- The use of wireline coring systems for coal seam sample recovery and subsequent testing of the coal seams for permeability using Sigra’s DST systems.
- The development and testing of the gas content while drilling system to enable gas content of coals and shales to be determined as part of normal production hole drilling.
- The study of wellbore stability in different stress and formations.
- The design and construction of well control equipment that was used at Lihir mine to permit drilling into hot wet rocks using Simcas down the hole hammer systems.
- The design of casing systems for use in groundwater production bores.
- The design and sizing of wells, screens and pumps.
Sigra can design suitable cement grouts to seal casings into boreholes or for the installation of piezometers. Sigra have a large size rotating viscosimeter that is suitable for testing grouts.
This broad range of experience enables Sigra to be able to design a suitable drilling programme for most operations. Our clients can benefit hugely from our range of experience across several industry groups.
For example Sigra could take a brief from a client and design a suitable drilling system including all aspects of the drill, drill string, casing, drilling fluid, hole stability, well control, sample retrieval and completion.