Abstract: Gas Exploration and Production in Solimões Basin

Rocha, Luis Otavio P.; J. M. Kinzel; and C. A. P. Magalhaes - Petrobras/E&P

The petroleum and natural gas exploration activities in the Amazon region began in 1917. In the early years, wells were drilled on the river margins, and prospects were based upon scarce geological data. The main exploration phase took place soon after the establishment of Petrobras in 1953, a remarkable increase in the number of wells drilled and the first applications (from the late 60's) of reflection seismic, this being initially along the river and eventually by sending helicopter-born work teams into the jungle itself, far from the rivers. During this phase, non-productive oil wells were discovered in the Amazon Basin. It culminated with the discovery of the Juruá Gas Province, in 1978, and the Urucu Oil and Gas Province in 1986, both in the Solimões Basin. Recently, three more gas fields were discovered in this Basin: Copacá, São Mateus and Taquaré. To date, 155 wells have been drilled, 64,603 km of 2-D and 3,983 km of 3-D seismic were surveyed in the Solimões Basin.

Currently, only the Urucu Province bears producing wells. The gas is processed at the Pólo Arara processing station and then re-injected into the Rio Urucu field in order to maintain the reservoir pressure as well as to store it for future use, thus preventing gas burning. To operate in remote areas within the dense rain forest, special techniques and procedures are necessary so that human, environmental and industrial costs and risks are reduced. Thus creative, pioneering procedures have been adopted to access the exploration area, to acquire geological data, to construct and maintain the roads and buildings, and, above all, to preserve the crews' living standards, such as: Slimhole Drilling, Rigless Evaluation, Air drilling and Fluid Injection.

The link between the producing gas fields and the consumption centers, by means of gas pipelines, makes economical exploitation feasible, but also requires special care to minimize and prevent environmental impacts. A gas pipeline is under construction, It was planned to link a gas producing well, situated in the Igarapé Pucá Gas Field, to Carauari City. This is part of a pilot project which aims to demonstrate that it is feasible to substitute diesel or fuel oil with natural gas in order to generate electrical power, establishing the development of outlying villages. The total automation of the plant is foreseen in the project, allowing long distance management by means of data transmission and satellite control. In bigger projects, the plan is to use, on a large scale, remote control automation facilities to operate the wells and separation stations situated in the distant jungle. The Pólo Juruá gas fields will be linked by a gas pipeline to the Pólo Arara production station. The gas will be reprocessed and transported through a pipeline to Porto Velho City, and also to Coari City, from the Pólo Arara; from here it will be transported, as far as Manaus. For such investments, an intensive control of all the risk is planned, which will render the maximum reduction in operation costs and environmental impact.

The natural gas business provides an excellent expectation of great gas demand in Brazil in the near future. It is estimated that in Brazil the share natural gas will play as a source of energy will jump from the current 2% to about 12% by the year 2010. Brazil's Amazon is the region which currently needs more useable energy. It has the country's second largest natural gas reserve, 26% of the country's total.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil