Industry needs to make big changes in shale well design, says CGG/Baker Hughes
CGG and Baker Hughes have called on the industry to pay more attention to the design of shale wells if the unconventionals industry is to have any chance of flourishing in Europe, where the success rate of wells and fractures will need to be much greater than it has been in the US. Making a presentation in Houston to mark one year since the two companies entered into their Shale Science Alliance, Nathan Meehan, senior executive adviser R&G at Baker Hughes said, ‘As an industry we are wasting billions of dollars drilling poor wells. Everywhere I look I see a phenomenal number of terrible wells. Too often the frack is being put in the wrong place.’
In the US and Canada this inefficiency has ultimately not affected the economic viability of wells, but in Europe, where environmental opposition to fracking is far higher, such an approach will not work and there will need to be fewer and more productive wells drilled. ‘In Europe we will have to take a dramatically different approach,’ added Meehan. ‘Industry estimates indicate that around 70 per cent of wells do not reach their production targets and 60 per cent of fractures are ineffective. Even at one of the most successful shale plays, Eagle Ford, which produces 500 barrels a day, 40 per cent of wells are ineffective. With typical well costs in the range of $6-8 million, this is a significant risk.’
Rob Mayer, senior vice president software and services at the CGG company Hampson-Russel, added that part of the problem is that currently many critical factors are being largely ignored when it comes choosing to well location: ‘Wells are being chosen mainly on thickness of the attribute and production of offsite wells. All wells aren’t created equal and there is a lot of heterogeneity in factors such as stress, brittleness and impedance, but we have difficulty validating these things.’
Combining CGG’s processing data laboratory and Baker Hughes’ downhole knowledge, the alliance has been carrying out tests at shale formations in Haynesville in North West Louisiana and the Marcellus Formation in New York State and has recently finished processing the data. The aim of the testing has been to use a broader range of geoscience data to continuously improve reservoir knowledge throughout the life of the field.
Tim Adams, vice-president of business development for Baker Hughes, said: ‘The tests are allowing us to demonstrate the petrophysical and geomechanical calibration of seismic attributes using borehole information (cores, cuttings and logs) to build more accurate predictive models. They have also given us the opportunity to explore the role of microseismic data in validating and calibrating reservoir models.’
The alliance is using near-wellbore mineralogy, lithology, rock strength, and natural fracture data derived from logging while drilling (LWD), coring, and wireline logging services from Baker Hughes and quantitative rock mineralogy from CGG to build a reservoir model. This information, along with the seismic data, helps to guide well placement and trajectory. To ensure maximum reservoir contact for lateral sections, the alliance uses Baker Hughes’ RNS Reservoir Navigation Services.
With Baker Hughes’ MFrac fracture simulation and modelling software and StarTrak LWD technology, coupled with CGG’s RoqSCAN wellsite mineralogical analysis from Robertson, fracture stage placement and parameters can be optimized.
Sophie Zurquiyah, EVP of CGG’s geology, geophysics & reservoir division, said: ‘We have seen a growing acceptance in the industry that more geoscience can improve success in the development of shale resources and a willingness to do more experiments and bring to the table information that we have not had in the past. They are going to want to optimize drilling wells and the environmental footprint has to be better as well. Production logs are perceived as damaging to the hole, but logs are really needed, especially where the well has tight economics. We need more sophisticated logging of information.’
Rob Mayer added: ‘Drilling and completion decisions need to be more focused on economics and engineering. The Barnett Formation in Texas was successful for companies based on who could drill the wells fastest and cheapest but there needs to be more effort put into design.’