Drilling coiled tubing

However, coiled tubing drilling is limited to slim holes, and the reliability of some of the drill string components such as downhole motors needs further improvement. Presently, the cost of building a new customised CTD rig limits the wider application of this emerging technology. 

J. J. Kolle. Coiled tubing drilling with supercritical carbon dioxide. Patent US 6347675,2002. 

Figure 6. Coiled tubing drilling, closed loop recirculating foam system surface layout.

New technology is applied to existing fields to enhance production. For example, horizontal development wells have been drilled in many mature fields to recover remaining oil, especially where the remaining oil is present in thin oil columns after the gas cap and/or aquifer have swept most of the oil. Lately, the advent of multi-lateral wells drilled with coiled tubing have provided a low cost option to produce remaining oil as well as low productivity reservoirs. 

Keywords production decline, economic decline, infill drilling, bypassed oil, attic/cellar oil, production potential, coiled tubing, formation damage, cross-flow, side-track, enhanced oil recovery (EOR), steam injection, in-situ combustion, water alternating gas (WAG), debottlenecking, produced water treatment, well intervention, intermittent production, satellite development, host facility, extended reach development, extended reach drilling. 

Chemically enhanced drilling offers substantial advantages over conventional methods in carbonate reservoirs. Coiled tubing provides the perfect conduit for chemical fluids that can accelerate the drilling process and provide stimulation while drilling [1471]. The nature of the chemical fluids is mainly acid that dissolves or disintegrates the carbonate rock. 

Mixed metal hydroxide drilling muds have been successfully used in horizontal wells in tunneling under rivers, roads, and bays for drilling in fluids for drilling large-diameter holes with coiled tubing and to ream out cemented pipe. 

R. C. Navarrete, J. M. Seheult, and M. D. Coffey. New biopolymers for drilling, drill-in, completions, spacer, and coil-tubing fluids Pt 2. In Proceedings Volume. SPE Oilfield Chem Int Symp (Houston, TX, 2/13-2/16), 2001. 

R. Rae and G. Di Lullo. Chemically-enhanced drilling with coiled tubing in carbonate reservoirs. In Proceedings Volume. SPE/Int Coiled Tubing Assoc Coiled Tubing Roundtable (Houston, TX, 311-318), 2001. 

Figure 11.1 Illustration of a closed-loop recirculating-foam system for drilling using coiled tubing. From Thomas and Wilkes [485], Copyright 2000, Cambridge University Press.

The most commonly used metals in drilling and well stimulation11-13 are low-alloy carbon steel (API Grades J-55, L-80, N-80 coiled tubing) quality tubing (grades QT-70, 80, 1000) chrome alloy steels (ASM Grade Cr-13, duplex steel). 

First, drill a 3/8" hole through the corK. Then drill t fo 3/8" holes in Lhe side of the bucket at the bottom and a quarter of the distance around from each other. Through one of these holes will run the condenser coil tubing and the other will allow the excess water to squirt into the sink. 

Moreover, today s reservoir drilling and exploration requires more advanced intelligent technology. One such technology could be in so-called electric coil tubing , where composite coil tubing could be corrsidered as a viable... 

One bus bar is insulated from the base plate. The tungsten tube is surroimded by a copper sheet box, to which a tightly woimd cooling coil is soldered. The brass baseplate is drilled for two other tubes, which serve as connections for a McLeod gauge and a vacuum pump. 

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