This paper reports a critical review of the operational principles and the most important completions techniques used in hydraulic fracturing in the U.S.A. and investigate whether they are applicable to the Posedonia geological and surface environment conditions in Europe. It is found that both cemented liner and open-hole with external packers completions wells have been used in shale gas developments. Plug and Perf and continuous pumping multi-stage hydraulic fracturing methods were respectively used. Low viscosity fracturing fluids are preferred to increase fracture complexity in brittle shale. Large stimulated reservoir volume by increase fracture density effective fracture half-lengths and use of proppant techniques to increase fracture conductivity. It is found that the Posedonia shale is comparable to several U.S.A. shale pays in terms of geological and petrophysical attributes (porosity, permeability, thickness, gas, oil and water content water). Therefore, we expect the multi-stage fracturing techniques developed in the U.S.A. to be largely applicable for the Posedonia shale. However, larger softness and greater depths of the Posedonia shale make more viscous fracturing fluids and fewer but much longer horizontal wells inevitable. Provided such longer horizontal wells are used, production rates similar to those reached in U.S.A. shale gas wells could be achievable.

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The potential for the exploration and exploitation of geothermal energy for greenhouses in Franekeradeel in the north of the Netherlands has been investigated. Available borehole and seismic data have been used for the evaluation of the subsurface. These data show that the Slochteren Formation sandstone reservoirs are very likely present at a depth of ca 3,000 m. These reservoirs are deemed to be suitable for the production of hot water. From interpreted 2D seismic lines could be inferred that the Slochteren Formation is around 200 m thick at the proposed location. Based on the local geothermal gradient, the temperature at the top is estimated to be around 100 ºC. At the surface location a fault zone is present in the subsurface complicating the siting of the injection and production wells. Towards the northeast the proposed reservoir is seemingly less faulted. A minimum transmissivity of 11 Dm is expected, based on the measured porosity in nearby boreholes and porositypermeability relationships in the surrounding area. A potential flow rate of 160 m 3 /h is hence inferred, leading to a thermal capacity of 11 MW t which can be delivered with one doublet. Different well configurations were studied. The conclusion is that deviated wells from the edge of the surface location towards the northeast carry the lowest risk at still acceptable costs. From financial analyses taking different options into account, it was concluded that geothermal energy can deliver significant amounts of renewable energy for heating of greenhouses. In the optimum situation, the cost price of heat amounts to 6,20 Euro/GJ delivering annual 202 TJ of energy. This price is below the current price (January 2008) of natural gas at 0,20 Euro/m 3 .

7his papar was seleoted for presentation by an SPE Program Committee following review of information contained in an abslract submitted by the author(s). Contents of the papar, as pfesentsd, have not bean raviawed by the Seciety of Petroleum Engineers and are subject to correction by the authcf(s). l%e material, as presented, dces not necessarily reflect enY positico of the Scciety of Petroleum Engineers, its officers, or members. Papers presented at SPE meetings are subject to publication raviaw by Editorial Committees of the Society ef Petroleum Engineare. Elecfrenic reproduction, distribution, or sterage of any part of this paper fef cmmercial purposes without the twitten consent of the Sociaty of Petroleum Engineers is prohibited. Perrniasion to reproduce in print is resfrictad to an abstract of not mora than 3JM word% illustrations mey not be copied, The abstmof must mntain conspicuous acknowledgment of Mere and by tiom the paper was presented. Write Librarian, SPE, P.O. Box 83383B, Richardson, TX 75083-3826, U. S.A., fax 01-972-952-9435. AbstractWith the increasing focus on creating possibilities to economically develop marginal fields, the basic rotary drilling concepts are being reviewed to reduce the costs of chilling wells. This paper presents a preliminary design of a Fast Connector, which reduces the make-up time, while the mechanical performance is comparable to that of conventional tool-joints. The geometry of this specific connection provides even some extra features, which are not possible with conventional tool-joints.