Enhanced Oil Recovery from Oil Fields with Bottom Water

Abstract

In Brazil, gas and oil exploration and production (E&P) is ruled by environmental laws that do not meet its characteristics of integrated and sequential development of its activities. Thus, every well drilling, for instance, must be licensed. On the other hand, there are mechanisms predicted in general and basic laws by which the industries may have easier ways to get environmental permits, taking into consideration the activity types. Unfortunately, this has not been observed by environmental control agencies, by this way becoming the issue ‘environmental permits in Brazil’ hard and ‘heavy’. In 1998, E&P in State of Esp rito Santo (called in this paper as Company), Brazil, got success in dealing with the state environmental agency (EA) about validity conditions of a future permit. The new permit, issued by the end of 1998, comprises Company's usual onshore E&P activities, and determines that they could be developed without individual (site) permits. This paper shows, via case study, how the agreement was established and how the negotiations between Company and the government EA were carried out. This agreement ended in a global E&P permit that allows usual E&P activities be started regardless of government formal approval, provided EA be communicated 30 or 60 days before the beginning of the activity. After this lack of time, the activity can be developed. The activities are in general well drilling, seismic survey, oil and gas production and increasing of oil and gas pipeline capacities. The main conclusion that comes from this paper is that an enterprise should use strict ethical principles when talking to an EA. This results in a relationship of confidence between the parts, and occasional difficulties that usually appear in this kind of process are more easily solved. Introduction In 1996, Company and the EA came to the conclusion that the environmental permits of the Company s activities could not be released well by well any more, seismic survey by seismic survey, pipeline by pipeline, as ocurred since 1991, when the activities began to be more strictly ruled. Before that time, since 1959, when the E&P activities started in the region, there were not environmental laws to rule them. There were more than 70 processes for getting permits to well drilling, seismic survey, etc, just for the activities set up from 1991 to 1996. Time spent to get permits caused frequent breakdowns in the Company's operations. Activities were sometimes delayed due to the absence of permit. Brazilian government had just taken from Company the petroleum monopoly. Regulations for the monopoly break established that, in a first stage, Company would have three years to define which areas it would intend to keep on its activities. In order to get the rights on the areas, Petrobras should present studies which justified the reasons in being interested in them. Not showing the studies, or if the studies were not considered enough to get a conclusion, the areas would be put up for auction. The winners would get the rights from the Government to explore and develop the areas. Thus, Company could not wait for months, sometimes more than a year, to get permits. It has to be also taken into consideration that E&P activities are repetitive and are developed in areas already occupied by other types of economic activities. Overview The Region. Most of the region is placed on low lands, with drainage channels built by farmers that develop cattle-breeding on very large farms, with hundreds of hectares. The upper lands, in the western and northern area, are usually used for eucalypts culture. It has low demographic density, and its soil is mostly organic. The region extends towards west until around 40 km far from the shoreline (Fig. 1). The phreatic level is very close to the surface, and the surface water are influenced by tide oscilations. This may lead to a temporary water salinization.

Hydrodynamic thickness of petroleum oil adsorbed layers in the pores of reservoir rocks

“…The primary and secondary (polymer/water injection) forces are expected to recover, at most, half of the oil in place, leaving the rest unrecoverable. This unrecoverable reserve will be the target of enhanced oil recovery techniques [1][2][3][4]. One question of interest in the oil industry is "Why do the primary and secondary forces produce only half of the oil in place?…”

An Effective Method to Improve Recovery of Heavy Oil Reservoir with Bottom Water Drive

“…Although the theory is not difficult to understand for a reservoir engineer, it is very difficulty to control water coning, especially for heavy oil reservoir with bottom water since the difference in specific gravities of oil and water is very small. Most of the previous studies focused on the prediction of critical production rate and water coning process for production well to control water coning by analytical models [2][3][4]6,7 , physical laboratory simulation 5,8,9 or numerical simulation technique [10][11][12][13][14] , artificial barriers [15][16][17] for controlling water coning and preventing by injection heavy fluids or chemicals 18,19 such as crosslinking polymers or gels. In the past 100 years, reservoir engineers tried to look for some effective techniques to control water coning for exploiting oil from reservoirs with bottom water.…”