Since the middle of the 1980s, the social and economic situation surrounding the international oil industries has been dynamically changed. This can be seen in lower oil prices, the decline in influence of major oil companies, the collapse of the Soviet Union, the increase of new E & P opportunities in developing countries, new technologies and so on. Due to these rapid and drastic changes, major international oil companies, including those in Japan have reorganized their corporate structures, improved their asset value and quality, re-evaluated E & P investment strategy. This report briefly outlines the background and the recent status of E & P activities of the Japanese oil industry.
Venezuela project and Australia project are recent typical overseas operator projects of Teikoku Oil Co.. Venezuela project is an on shore reactivation and development project, and Australia project is an offshore exploration project. Operational environments are fairly different. Each project selected own way of operation in order to achieve cost effective drilling operation.
The first commercial oilfield in Australia was discovered at Moonie in 1961 and was put into production in 1964. Australian oil production rose sharply in the latter half of 1970's as a result of the discovery of Barrow Island in the North West Shelf (NWS) and Bass Strait offshore fields. Total oil and natural gas production in 1996 was 540, 000bbl/day and 2, 622MM cf/day respectively. In Australia, more than 90% of total oil and gas production is from offshore fields. Japan Drilling Company, through its operations with two jack up rigs in the NWS area over the period of six years from 1991 to 1997, had a chance to monitor the various projects in the state of Western Australia. In 1996, Western Australia has become the largest oil and gas producing state in Australia, and this trend is expected to continue. This report will outline the current projects and future developments in Western Australia and the Timor Sea, as well as the oil and gas industry of Australia in general.
This paper describes the rig operations of Abu Dhabi Oil Co., Ltd. (ADOC). ADOC has been operating three offshore fields (Mubarraz, Umm Al Anbar and Neewat Al Ghalan) located about 60 to 100km off the coast of Abu Dhabi in Arabian Gulf where fifty-four (54) wells have been drilled. Twenty-five (25) wells out of fifty-four (54) have been completed as electrical submersible pump (ESP) producers. The total number of rig operations has reached to three hundred and eighty-five (385) since the first well was drilled, with half of the operation related to ESP programs. ADOC uses the cantilever jack up type rig because of the shallow water depth and workover re-entry requirement. Typically, about seventy (70) people are on board, from the rig contractor, the service companies and ADOC. As so many people are working on the rig, it is essential to keep good communications with the rig superintendent and the engineers from service companies and have meetings before conducting stimulation, cementing or other sensitive operation. Logistics is also key to efficient rig operation.
These days, subsea development solution is getting quite common option for a marginal field development. In PL089 where Idemitsu Oil Development Co., Ltd. has 9.6% share, subsea development system has been applied for Snorre, Tordis, Statfjord East and Vigdis fields. It seems to a person who has no experience about subsea development/completion that “subsea completion” is very special. But there are no major difference between platform completion operations and subsea completion operations except subsea completion requires special tools for installing tubing hanger and subsea tree. Since people can not access directly to the subsea systems, special attention is paid for operation process and procedure as well as company's internal control system.
Cambodia Petroleum Exploration Co., Ltd. (CAMPEX) drilled its third exploratory well named “Poulo Wai-1” in August 1996 in the Block III of Offshore Cambodia. In order to select a drilling rig, CAMPEX studied the two contract systems: an Assignment/Reassignment Agreement system (“Assignment”) and a Tender system. It was concluded that “Assignment” was more cost effective than a Tender on this particular well after a series of negotiation with Enterprise Oil Exploration Ltd. (Enterprise). CAMPEX decided to adopt “Assignment” and acquired a drill ship. The main points of the agreement were that CAMPEX was assigned the right and the duty of one option well from the original agreement made by Enterprise and that CAMPEX shared a mobilisation and a demobilisation cost of the rig, a rig modification cost and a time-writing cost with Enterprise. For the sake of the adoption of “Assignment”, CAMPEX saved the total well cost significantly.
A three-dimensional two-phase basin simulator, BASIN3D2P, was applied to the offshore Niigata basin to make it clear the problems of basin simulation studies for practical exploration activities. The studied area was about 40km×45km, and was divided into 1, 258 grids horizontally, while ten horizons were deposited sequentially during about 16 m.y. Input data sets for the calculation were prepared by using data from exploration wells, interpreted seismic reflection profiles, results of geochemical measurements, and so on. The result showed that three-dimensional evolution process of the basin through geological time scale could be simulated by BASIN3D2P, and by modifying heat flow history, relative permeability curves, amount of initial organic materials, and duration of the calculation, we could improve the fitting of the calculated results with the observation. We, lastly, discussed possible practical usage of three-dimensional basin simulation to the estimation of oil accumulation in peripheral structures of the developed/depleted oil fields.
Underbalanced drilling is one of the quickly developing technologies in the world. It enables to lower the development cost by increasing the oil production per well and by avoiding the possibility of drilling hazards such as lost circulation, differential sticking. Further, production impairment reduction is significant in underbalanced drilling because no fluid invasion occurs. This paper introduces surface and downhole equipment, tripping procedure, limitation of the existing underbalanced drilling and completion technology.