Bridging the Stimulation and G&G Worlds
Authors: Farabee Mark , Trenholm Peggy , Dodds Rich 
Published: July 2010

Finding sufficient information to help drive better decisions is not an issue in the oil and gas industry—this industry is one of the most data-intensive in the world. The challenge is interpreting all the data we possess. Furthermore, various disciplines or departments hold critical information that might be useful to others, but not often can it be shared because of technology or process issues or simply because it may not be known that others could make decisions with it. How can asset teams leverage all the information they possess to make better decisions and improve production and recovery rates? In particular, what can be done to bring together the vast amount of information that both the geological and geophysical (G&G) and stimulation worlds have?

What is needed is a solution that allows stimulation data to be integrated with geological and geophysical data to understand how the reservoir will fracture and respond to stimulation treatment. This solution will allow for better decisions to be made about how overall reservoir production can be improved: microseismic events can be viewed in context of G&G data to refine stimulation treatments; attributes of seismic information, such as curvatures, can be used to understand how the formation might fracture and help drive well placement and perforation strategies; experts who do not traditionally weigh in on fracture design (i.e., geophysicists) can now have a seat at the table to help improve stimulation placement and treatment design for improving stimulation effectiveness.

In new plays, like some of the unconventional shale gas plays, little is often known initially about how the formation will react to a given stimulation treatment. In such cases, a trial-and-error approach is often used; however, a strategy that might have been successful in an older shale play might not be successful in a new shale play, as with traditional sand reservoirs. The ability to use seismic and other data, as well as expertise from other disciplines, might greatly enhance overall success in new areas.

Introduction

Information is critical to making decisions, but how do we get all of the information we need into the hands of the right people at the right time? How can we create a collaboration environment in which correlations and trends can be visualized and verified? And, more importantly, how do we create a workflow that allows us to continuously optimize results quickly, even in real-time? Nearly every service company and operator has an initiative to drive efficiency by better integrating data and disciplines. Many are steadily making improvements in data access, and this paper presents a software tool for visualizing microseismic events in the context of the geological and geophysical background or geomechanical model of the formation and a workflow to optimize stimulation performance. These steps bring together geoscientists and fracture engineers so that they can make decisions collaboratively and improve the return on stimulation investment.

Why, and where, is this important? In tight gas and shale plays, production of a well is dependent on the effectiveness of hydraulic fracture treatments. It is commonly said: " If we do not fracture it, we do not produce it.?? The question then becomes, beyond waiting to realize production, how does an operator know if a formation as been effectively stimulated?

Microseismic fracture mapping allows us to visualize the physical location in the formation that was treated, or at least disturbed by the treatment. Fracture mapping removes the guesswork about whether the treatment stayed in zone until actual production numbers are available. Reference 22 provides examples of the benefits of integrating microseismic mapping in the Overton Field of East Texas.