As previously stated in the SPE’s petrowiki (published from Petroleum Engineering Handbook, Volume II – Drilling Engineering), that the emphasis on drilling technologies at the turn of the century became particularly important because the remaining oil and gas supplies, particularly in rich countries like the United States, are concentrated in mature provinces of substantially degraded basins or in challenging drilling environments. Drilling technologies must also provide secure, cost-effective access to subsurface geologic formations in order to evaluate/optimize their production capacity or to extract the resource that already exists. Simply saying is “economic». In high-cost environments like the deepwater offshore where maximum efficiency and optimization of time on location are highly needed. Some of these technologies, we mention:
Dual Gradient Drilling Systems (DGDSs): often referred to as riser less drilling. It is generally accepted that DGDS is required in water depths of more than 5,000 ft, It is caused by the reduced fracture gradient of formations below the mud line resulting from the reduced weight, or gradient (0.5 vs. 1.0 psi/ft), when seen from a drillship working at sea level, the water above the mud line causes the mud line to rise.
There are other Technologies tested with the onshore field and are considered essential to economics for enabling further exploration of ultradeep (> 20,000 ft) onshore petroleum resources, among of which we mention:
Expandable tubular offers the possibility of digging a “mono bore hole” and drilling to lengths not constrained by the original hole diameter. As a result, the focus on tubularly has concentrated on the expandable casing. Shell and Halliburton formed a company, Enventure.
Production casing can be run inside the expanded form of the casing with the same diameter as this concept. It will allow, casing to be set at will or as needed, without a penalty in completed depth. Lost-circulation zones, swelling shales, and other drilling problems can be put behind pipe as necessary.
Casing Drilling: this is not a new concept for the mining and water-well industries. However, modifying the tools and materials for oilfield use and extending drilling depth beyond a few thousand feet is new. This new approach, called Casing Drilling, was developed and field-tested, and culminated in a successful demonstration to ≈ 9,500 ft early in 2002 in South Texas by Tesco Corp. and its partner, Conoco. The demonstration was the result of > 5 years of development that included the development of tools for directional drilling. The demonstration resulted in an actual overall drilling time reduction of 17.5% and a potential for as much as a 33% reduction.
Even microsystems that represent a quantum leap in the size, and/or capability of currently available systems, is tied to the interest in “smart” drilling and the demand for increased information and reliability. For example, fiber optic devices sensors can be of great benefit in building more complicated sensory and communication networks.
The use of microsystems has opened the door for a new concept in drilling known as micro-drilling, which can reduce drilling cost to the point that it could be considered a part of “predrill” prospect development That feasibility is being investigated at Los Alamos Natl. Laboratory under a grant through DOE’s National Gas and Oil Technology Partnership Program.