Symmetrix Overburden Drilling System & Reverse Circulation Drilling System
To drill boreholes by symmetrix method or reverse circulation method
Drilling Technique & Equipment
Prior to this method of drilling being utilised the site will have been prepared and a thorough safety check been carried out.
The rig will be reversed over the drill target site using every care to get as near to the proposed drill target as possible. When a secure base for the rig has been achieved the mast will be erected and final levelling will take place.
Rotex OY Symmetrix drilling method using symmetrix nominal 300mm system or equivalent system.
This drilling method comprises full face drilling with reamer shoe, slightly oversized, attached to nominal 300mm threaded steel casing. Following uPVC & gravel pack installation, where specified, retrieval of steel threaded conductor symmetrix casing is assisted by the oversized hole to the outer casing and in addition our Drill Rig has a floating bottom clamp to assist the rotary head with pull back offering a combined pull back of 50-60 ton.
We can offer a Symmetrix system with an ID of 273mm, allowing installation up 250mm screen/casing string without gravel pack or grout seal or 200mm with gravel pack and grout seal.
Reverse Circulation Drilling: The use of dual wall drill pipe combined with drill collars/stabilisers and special hard formation bits mean a cleaner drill site and drill system that is environmentally 'greener'. Drilling cuttings are directed into holding tanks or pits and all surplus clean drill fluid is re-directed down hole as part of the drilling operation. This method allows borehole advancement by" mudding" up unstable openhole with appropriate mud mix/polymer to drill to target depth and install uPVC string prior to removing mud out of hole by appropriate well development techniques.
To be advised.
Well Head Finish
The casing to be finished above ground level with full specification well head finish per tender outline.
Borehole logging & Sampling
A detailed borehole log is to be provided. Samples of sediment encountered at 1m intervals are to be left in a chronological order on site near the borehole.
Drilling Equipment & timescale
See review outlining Drill Rig Specification. Also attached provisional Work Schedule outlined in Gantt chart format.