Page 38: of Offshore Engineer Magazine (Apr/May 2014)

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columns extending below structural columns extending below structural

Fig4: Geological realization of the Lancaster discovery spill resulting in long hydrocar-spill resulting in long hydrocar- portraying well paths in bon columns and ? ank accumula-bon columns and ? ank accumula- relation to the seismically tions. This hydrocarbon distribution tions. This hydrocarbon distribution mapped fault network.

is in part due to the presence of highly is in part due to the presence of highly effective lateral seals, but is also due to effective lateral seals, but is also due to logging tool (PLT) integra- permeability anisotropy and heterogene-permeability anisotropy and heterogene- tion. Fluid typing established ity within the hydrodynamic fracture ity within the hydrodynamic fracture

Geology & Geophysics through bottomhole samples network. Such poroperm character-network. Such poroperm character- procured under variable choke istics are in? uenced by long istics are in? uenced by long size and ? ow rates. geological histories geological histories •

Establishing reservoir behavior of subaerial of subaerial away from the borehole environ- exposure exposure ment through transient pressure and tectonic and tectonic analysis modelling combined activity, activity, with Petrel, sector and discrete with frac-with frac- fracture network (DFN) models. ture network ture network

The analytical components comprising The analytical components comprising permeability permeability

Hurricane’s work? ow are necessitated by Hurricane’s work? ow are necessitated by being enhanced through being enhanced through

Lancaster the fact that fractured basement reser- the fact that fractured basement reser- Lancaster epithermal and hydrothermal epithermal and hydrothermal discovery (Fig. voirs are classi? ed as Type 1 Fractured voirs are classi? ed as Type 1 Fractured discovery (Fig. dissolution/abrasion combined with tec-dissolution/abrasion combined with tec- 4), the data from which supports Reservoirs, in that the poroperm system Reservoirs, in that the poroperm system 4), the data from which supports tonic reactivation of pre-existing joints tonic reactivation of pre-existing joints is provided entirely by a natural frac- a 2C resource estimate of 207MM boe and faults. ture network. This means, gaining and recoverable.Hurricane’s next Lancaster The Lancaster resource range so far developing an early understanding of the appraisal well, scheduled for 2Q 2014, is identi? ed is in part based on the poten- distribution and characteristics of the designed to test the ? ow potential of the tial of stratigraphically trapped oil identi- fracture network is essential. Speci? cally reservoir through the drilling and test- ? ed through pressure surveys (modular an understanding of the hydrodynamic ing of a 1km-long horizontal basement dynamic tester) and gas returns measured fracture network is key for optimum well section. as part of mud-logging acquisition. placement. The well is targeted at evaluating However further appraisal wells, includ-

Consequently, wells are targeted to the P90 oil volume that resides within ing ? ank and deep penetrations, will be intersect faults which are identi? ed from structural closure (Fig. 5) by penetrat- required to re? ne the stratigraphic upside 3D seismic, the faults being considered ing nine seismically mapped fault zones and also the presence and characteristics important targets as their associated fault and undertaking a series of open hole of an aquifer.

zones are considered to have enhanced tests, designed to evaluate ? ow rate, as If Hurricane’s appraisal efforts con? rm reservoir properties. An example of well as reservoir response to shut in and the anticipated oil-in-place and reser- this concept is seen in Fig. 3, which build up. The 25-day testing program is voir deliverability, the Lancaster ? eld is shows an interval of borehole that has planned to demonstrate a commercial expected to be produced via a phased been identi? ed as a fault zone from 3D ? ow rate, which, if achieved, will result development, utilizing an existing sus- seismic an interpretation, corroborated in the well being suspended for use as a pended well and the planned 2014 hori- by image log analysis and demonstrably future producer. zontal well in the ? rst stage of develop- preferentially productive as seen through The trapping of hydrocarbons within ment. Early oil from such a development

PLT logging. basement can include a signi? cant is anticipated for 2018.

Hurricane has drilled two wells on the stratigraphic element, with hydrocarbon

Robert Trice is CEO and founder of

Hurricane Energy. He has a PhD in Geology from Birkbeck

College, University of

London, and gained the bulk of his geoscience experience with Enterprise Oil and Shell. He has worked in ? eld development, exploration, well-site operations and geological consultancy.

Robert has held the position of Visiting

Professor at Trondheim University (Norway) and has published and presented on subjects related to fractured reservoirs and exploration for strati-

Fig. 5: Well path showing horizontal reservoir section and seismically mapped faults.

graphic traps.

April 2014 | OE oedigital.com 40 000_OE0414_G&G-1_trice.indd 40 3/23/14 12:06 AM