In recent years, private oil and gas companies have to deal with various obstacles. Those include oil and gas prices volutilities, procurement delays and cost surges of material and equipment, human resource shortages, so called resource nationalism, and severe competition with national oil and gas companies. Some private companies are focusing on deepwater exploration and development, natural gas exploration and development with liquefaction (LNG) plants and unconventional oil and gas such as oil sands and shale gas, which need high level of technologies as well as know-how other than oil and gas exploration and development, such as liquefaction and marketing. However, private oil and gas companies might have to step further, since some national oil and gas companies tend to be aggressive to catch up private oil and gas companies in some areas such as deepwater, which could make competition even severer.
On Feb. 22nd of 2009, Operator ship of LF13-1 Oil Field was transferred from Tokyo 3 company (JAPEX New Nanhai, New Huanan and NMC) to CNOOC after it's 15 years commercial production period and petroleum contract terminated.. LF13-1 Oil Field is located at south china sea, about 250 km south east of Hong Kong in a water depth of 145m. Production of this oil field started in October 1993. Cumulative Production from the beginning until the termination of petroleum contract reached more than 70 MMbbl, which was more than double of ODP forecast. At the beginning of this project, Tokyo 3 company and CNOOC faced serious financial problem because of the soaring of construction cost and low oil price. In spite of the difficulties, 4 companies jointly made every effort to survive this oil field. Totally 7 development drilling campaigns were carried out to maximize the production from this oil field and made every efforts to lower the operation cost. This paper outlines exploration phase, development phase and production phase of this project to know how this marginal oil field became excellent oil field at the last.
The Nam Rong-Doi Moi field is located in the south of the Cuu Long basin, which produces oil from the fractured granite reservoir. The pore system within fractured granite was investigated based on the well data, and a hypothetical reservoir model was proposed. The fractured granite reservoir consists of “fault breccia”, “damaged zone” and “un-deformed zone”. Both “fault breccia” and “damaged zone” show low to fair permeability while “un-deformed zone” shows very low permeability nature. There occasionally be high permeable “channel structures” within “fault breccia”, and this mixed pore structures create a high permeability contrast within granite, and the fluids in the fractured granite reservoir behave as a dual porosity reservoir. In order to predict the fault/fracture distributions within the granite, the “Controlled Beam Migration” technique was applied to the 3D seismic data in the NR-DM field. The results of reprocessing show an improvement to image high-dip structures within the granite, which corresponds to the actual flow zones in the well. The NR-DM field is still under development and will be studied further with newly acquired data to optimize the development and production.
Abadi Gas Field was discovered by INPEX Corporation in 2000, singlehandedly. This discovery was made in a remote frontier area of Arafura Sea in Republic of Indonesia. The discovery was in 400-800m sea depth and more than 100km away from the nearest island, with Timor Trough existing in between. INPEX subsequently carried out 3D Seismic Surveys and multiple delineation drilling campaigns, which proved that this field is a giant gas field. This paper describes Geological philosophy based on which the tract was obtained. The geological framework of this area , based on 3D Seismic and exploratory / delineation drilling campaigns. The use of 3D Seismic data, innovative way to effectively calculate reserves distribution and partial perforation DST to evaluate vertical communication are addressed in some detail. The way forward for the development of this field is touched on.
The Sakhalin 1 Project is one of the oil and gas development projects located on the northeast shelf of Sakhalin Island, water depth is 10 to 60 meters and the thick ice covers the area 6 to 7 months a year. The project was declared commercial by the Sakhalin 1 consortium in October, 2001, and started development period from this year. Total recoverable reserves are estimated at 307 million tons of oil and 485 billion cubic meters of natural gas. This project consists of three fields, Chayvo, Odoptu and Arkutun-Dagi, which are planned and conducted to develop in phases 1 to 4, using both offshore and onshore wells. Many of these wells will be drilled using a new drilling technique called ERD (extended reach drilling), which allows oil and gas targets to be drilled by the rig located a great distance away. The first phase of development is focusing on the oil production of Chayvo and Odoptu fields, and the start of the oil production from Chayvo field was commenced in October 2005. The oil production reached to 250 Kbpd at peak rate in 2007. The produced oil is transported through the pipeline to the marine tanker terminal at Dekastri Located Khabarovsk province. Large marine tankers are escorted by icebreakers during winter season using a new developed ice passport concept for the year-round export operations. These advanced technologies were applied to reduce the overall cost of development and to minimize environmental impact.
Natural gas hydrates in sediment are expected to be developed as a resource of natural gas and have been studied as a possible future energy resource. Gas permeability and water permeability in the methane-hydrate (MH)-bearing sediments are important factors for estimating the efficiency of producing methane gas from the natural gas hydrate sediment. Permeability of MH-bearing sediment is considerably affected by several properties of sediment, i.e., pore-size distribution, porosity, cementing, MH saturation, and MH-bearing features. There is no “universal” equation of permeability related with these properties that is applicable to all porous media including MH-bearing sediment. In order to clarify the relation between permeability and these properties, permeability, grain-size distribution, porosity, pore-size distribution, and specific surface area of glass beads and sandy sediments have been measured. The grain-size distribution has been measured by a dynamic laser light scattering-diffraction system. Mercury porosimetry has been used to measure porosity, pore-size distribution, and specific surface area. Proton nuclear magnetic resonance measurement combined with a permeability measurement system was used to characterize the porosity, pore-size distribution and the permeability. The permeability was measured by water. As a reference, four empirical equations of permeability, i.e., the Krumbeim and Monk equation, the Kozeny-Carman equation, an approximated equation using mercury porosimetry data, and the Schlumberger Doll Research equation, which incorporate factors such as grain size, porosity, pore size, and specific surface area, were scrutinized for calculating permeability. A semi-empirical (SE) equation of the permeability of glass beads and sandy sediment has been derived based on the Kozeny-Carman equation by pore-size distribution and porosity that had been measured by mercury porosimetry. This SE equation has been approximated by the relation of porosity, pore-size distribution, tortuosity, and specific surface area of the sediment. The permeabilities calculated by the SE equation correspond well to the permeability measured by water flow.
Rock magnetic property is utilized for oil exploration on the basis of three parameters : bulk magnetic susceptibility, remanent magnetization and anisotropy of magnetic susceptibility (AMS). Initial magnetic susceptibility obtained from non-oriented borehole samples is a crucial parameter for reliable modeling of geomagnetic anomaly. Information of remanent magnetization and AMS derived from oriented core samples provides us with insights into tectonic movement and microscopic fabric of reservoir, respectively. As a case study, rock magnetic experiments are presented, using oriented granite cores obtained from the Akebono SK-4D borehole in the Yufutsu area, Hokkaido, Japan. The analyzed samples at the top of the Cretaceous basement are characterized by relatively low magnetic susceptibility and stable, easterly-deflected thermoremanent magnetization that implies tectonic rotation. Maximum axis (K1) of AMS coincides with the intersection of two fracture systems within the granitic basement rocks, which implies the direction of maximum permeability. AMS parameters, reflecting microscopic alignment of minerals precipitated on fracture surface, may be useful to assess properties of fractured reservoir.