Cracking the unconventional nut has been on the radar of the geophysical industry for quite some time now. Scientists have been looking for attributes that differentiate between brittle and ductile zones using high-resolution and sometimes multicomponent seismic datasets and even examining core samples at the nano-scale to figure out how hydrocarbons are entrapped within the rock matrix.

Drilling engineers just want to get on with their jobs, and often these types of analyses add to the timeline. Geotrace is offering a new line of products that answer engineering questions without taking months to do it.

But convincing the industry has been a challenge.

Gary Perry, head of Western Hemisphere Reservoir Services, said that the “drill, baby, drill” mentality toward shale plays has inevitably led to very mixed results. “People are learning a lot of lessons and relearning a lot of lessons,” he said. “Every time there’s a new resource play, people say that you can just drill anywhere and all of the wells are going to produce about the same. Every time, without exception, that turns out not to be true.”

Geotrace starts with 3-D seismic data and then runs a model-based inversion and a stochastic risk analysis workflow. “This provides clients with the quantitative risk anywhere in the reservoir,” Perry said. With this process, for example, scientists can measure a dynamic Young’s modulus, calibrate it with the core analysis, and convert the dynamic properties into static properties. “The static Young’s modulus helps drilling engineers know where to drill and completions engineers know where to complete,” he said. “And sometimes it’s just as important to know where not to complete.” The overall process takes just a few weeks.

Given the proper amount and quality of input data, Perry said that the resolution on the completed dataset can be as fine as 3 m to 4.5 m (10 ft to 15 ft).

The results are remarkable. One Eagle Ford client estimated that it saves US $1 million per well by not completing in areas with low total organic carbon or high fracture density. Another client reported that in a 78-sq-km (30-sq-mile) area it was able to do 30% less drilling and fracing with a 40% increase in production. The process works just as well in conventional and offshore plays, Perry said.

In addition to saving time and money, the understanding gained through this technology has environmental benefits in terms of water savings as well as the avoidance of induced seismicity. The fine resolution enables operators to see faults that might be invisible on conventional seismic, allowing them to avoid them during drilling and reinjection.

Overall, this type of integrated approach offers major benefits while costing a fraction of the drilling and completions operations. “The better you understand the subsurface, the more money you’re going to make and the less damage you’re going to do to the environment,” Perry said. “That’s the bottom line.”

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