In a rare tribute to the energy industry, scientists have praised one company's record in exploiting an African oilfield.
By Alex Kirby
BBC News Online environment correspondent
They say Shell's field has more wild creatures than the surrounding national parks.
Drilling areas are small
The company says its environment policy has changed radically in the last 30 years.
It is working with the scientists on an international code of practice for other companies in sensitive areas.
The scientists' surprising endorsement of Shell's work is featured in Oil's Well?, a film made by Television Trust for the Environment (TVE) and shown in its Sustainable World series on BBC World.
The scientists, from the US-based Smithsonian Institution, are completing a two-year study of Shell's operations in its Rabi oilfield, in the central west African state of Gabon.
The world is losing 10 million hectares (25 m acres) of rainforest annually, though Gabon's is better protected than that of many countries: 85% of Gabon remains forested.
The Smithsonian team has been working with local scientists to compile the most detailed study ever undertaken of the Gabonese forest's biodiversity.
Together they have found many more species than the Americans had expected - at least 95 sorts of amphibian, for example.
The preliminary survey results show the Rabi field has a higher level of biodiversity than even the surrounding national parks.
Forest left intact
Shell tells the film crew about the techniques it is using to try to minimise its impact - specially narrow forest roads, for instance, whose verges are seeded with a mulch of indigenous plant seeds and nutrients to encourage growth and prevent erosion.
Land clearance around the wellheads is kept to a minimum, and no permanent settlements are allowed in the forest.
Gabonese scientists worked in the study
Laura Jackson, of Shell Gabon, explains how technology has advanced: "Recent developments in drilling mean that we no longer have to limit ourselves to vertical holes through the reservoir.
"Now we are able to use our drilling tools to turn the corner and to drill 90 degrees through the reservoir.
"So that should reduce the number of wells we have to drill and also helps our production in the shorter term."
Brian Ward of Shell Africa says: "I guess 30 years ago we would have looked at the environmental impact more as a reactive response to what we were doing, for example cleaning up any mess we had made, oil spills and so on.
"And latterly... we are really talking about how we can pre-empt damage, how we can design into our projects environmental protection... "
The Smithsonian scientists say the company is acting on many of their recommendations, often with encouraging results.
The biodiversity count in Rabi is high
One says: "When I was first told we were doing a survey of an oilfield in Gabon, I wasn't quite sure what to expect.
"Typically, as a conservationist, when I think of the oil industry and so forth, it equates to habitat loss, contamination of wetlands and so forth.
Involving its peers
"So I suppose my expectations were rather low. Right now we are at Rabi, and there is a swamp just on my left here, which is just 200 metres off one of those gas-burning flares, and there are at least 10 different species calling from them.
"They are doing very well, and it is comparable to swamps nearby. This site still maintains good species diversity and very strong, viable populations of amphibians...
"As long as your overall system is still functioning at a very high quality, small compromises here and there are something we should learn to live with."
Shell and the Smithsonian are now working on an international code of practice for sensitive areas with other energy majors including BP, Statoil and Chevron Texaco.