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Collaborating Authors
Results
Cement Placement with Tubing Left in Hole during Plug and Abandonment Operations
Aas, Bjarne (IRIS/DrillWell) | Sørbø, Jostein (IRIS/DrillWell) | Stokka, Sigmund (IRIS/DrillWell) | Saasen, Arild (Det Norske Oljeselskap) | Statoil, Rune Godøy (SINTEF Petroleum Research/DrillWell) | Lunde, Øyvind (SINTEF Petroleum Research/DrillWell) | Phillips, Conoco (SINTEF Petroleum Research/DrillWell) | Vrålstad, Torbjørn (SINTEF Petroleum Research/DrillWell)
Abstract Well abandonment operations can be very time-consuming and costly, and thousands of wells need to be permanently plugged and abandoned offshore Norway during the upcoming years. One possible way to reduce costs during P&A operations is to leave most of the production tubing in the well, as this would save significant rig time. A major concern with such an approach is, however, whether the cement will properly displace the original fluid, due to lack of tubing centralization and possible unfavorable flow dynamics in the annulus. In this paper, we demonstrate by full-scale experimental tests that it is possible to obtain good cement placement when the tubing is left in the hole, with and without control lines. Full-scale tests have been performed with both conventional and expandable cement to determine the sealing ability of annulus cement when tubing is left in hole. The quality of the cement placement was evaluated by pressure tests with water; where leakage rates and pressure drops over the test sections were recorded, and by visual inspection after cutting the test assemblies at different places. It is seen from the experiments that cement is well placed in the annulus when tubing is left in hole, but some microannuli are detected.
- Europe (0.90)
- North America > United States > Texas (0.46)
- North America > Canada > Alberta (0.28)
Long Reach Well Concept
Stokka, Sigmund (IRIS) | Cayeux, Eric (IRIS) | Gardner, David (IRIS) | Kragset, Steinar (IRIS) | Lohne, Hans Petter (IRIS) | Randeberg, Erlend (IRIS) | Skadsem, Hans Joakim (IRIS) | Aas, Bjarne (IRIS) | Kyllingstad, Henrik (Hole in One Producer) | Larsen, Torgeir (Wintershall) | Saasen, Arild (Det Norske Oljeselskap and University of Stavanger)
Abstract Current Extended Reach Drilling (ERD) well technology limits the well lengths to roughly 12 km with a horizontal departure of approximately 10 km. This paper presents a concept that enables simultaneous drilling and completion with an aim to substantially extend well reach and with an ultimate objective of constructing 30 km long production wells. Longer reach wells can be used to drain remote reserves using existing production facilities, as well as provide a means to access reservoirs located beneath environmentally sensitive areas. The key technology elements that enable the concept to construct long reach wells are multiple sliding packer traction units in combination with a dual casing drilling system, comprised of a casing with an inner tubing. The sliding packer traction units provide two primary functions; continuous well control along the length of the borehole and traction to overcome axial friction. In addition, the traction packers provide a stable bottom-hole drilling platform avoiding the occurrence of drilling instabilities such as stick-slip, which can damage conventional bottom-hole assemblies and the drill bit in particular. The dual casing provides the conduit for drilling fluid circulation to the bit and cuttings transport to surface. The drilling fluid is pumped through the annulus formed between the casing and inner tubing. The drill cuttings are transported to surface through the inner tubing, ensuring efficient cuttings transport with a low-pressure loss. The concept has been developed through a five-year project, kicked off in 2010. A prototype has been built and tests have shown that each sliding packer traction unit is able to push the drill bit or pull a completion string with a large axial force in excess of the estimated requirement. In the paper, elements of the system are described in detail and the results of the full-scale yard tests are presented. The concept represents a new well construction method incorporating advanced completion technology. It enables drilling and completion of long reach wells and can operate in areas with complex pressure regimes, such as can occur from pressure depletion due to production or pressurizing as a result of the injection of water or gas. Well control is provided by packers placed in pairs that seal off the annulus at predefined intervals along the drill string. Production takes place through a large inner diameter. It is a well construction method with no flat time.
- Europe > Norway (0.46)
- North America > United States (0.28)