Technology for measuring rock properties downhole, especially in carbonate formations, becomes more sophisticated each year – including right now.
Technology for measuring rock properties downhole, especially in carbonate formations, becomes more sophisticated each year.
As it does, pulling together the different kinds of information becomes more difficult.
In June, Schlumberger commercialized a new product designed to help address some of the challenges presented by carbonate formations.
Petrophysicist Raghu Ramamoorthy has been instrumental in developing the technical aspects of the system, Carbonate Advisor*, and introducing it in the Middle East.
Speaking by phone from Abu Dhabi, Ramamoorthy said the system integrates data from advanced and conventional logs. In the past, Ramamoorthy said, he would have to string together several software packages to assimilate information from borehole nuclear magnetic resonance, electrical imaging and other wireline readings.
He said the product pulls together almost three decades of work and is based on an approach articulated by the late Gus Archie, an AAPG member known as the "Father of Petrophysics." The product integrates advanced and conventional logs to characterize the pore geometry.
The analyst needs to understand the rock geometry, which in siliciclastic formations is linked to mineral composition, Ramamoorthy said.
"In carbonate formations, the geometry is not necessarily linked to mineral composition," he said. "In sandstone, we may only need (conventional) log information to make a decision.
"But carbonates keep dissolving and redepositing," he added. "To really do petrophysics, we need those advanced logs."
'Greater Geological Insight'
Nick Heaton, the company's product champion for wireline services, said ever-more sophisticated measurements must be integrated to determine how fluids move and are produced.
Speaking from Paris, France, Heaton said Carbonate Advisor exploits the "jewels" from each kind of measurement.
Ramamoorthy said data from Source A and Source B "both bring something to the table," but the sum of the two adds "greater geological insight."
The final display "gives the best answer possible from each piece of information to arrive at the best single solution," he said.
Ramamoorthy said the product speeds and optimizes the analysis of various sources to help make short-term critical decisions, such as which rocks or fluids to sample, and longer-range decisions such as what zones to put on production today or tomorrow.
Heaton said Carbonate Advisor has been deployed in carbonate reservoirs in the Middle East (the largest), North and South America, India and the North Sea.
Schlumberger officials said the service is being run by both national and international oil companies.
Schlumberger estimates more than 60 percent of global oil reserves and 40 percent of gas reserves are held in carbonates. The Middle East holds 62 percent of the world's proved conventional oil reserves and 40 percent of gas reserves, the vast majority of that in carbonate reservoirs.
(* – mark of Schlumberger.)