Thursday, August 19, 2010

Another "First" for North Dakota; Microseismic Arrays; The Halo Effect Of Fracking

Largest array: North Dakota has the largest buried microseismic array in the world, Geo News, July, 2010.

Other stories, same subject:

World's largest buried seismic array, Williston Basin, Whiting Oil in MicroSeismic:
Headline: MicroSeismic, Inc. Announces Completion of World's Largest Buried Array in Williston Basin for Whiting Oil & Gas Corporation

Story: HOUSTON - March 10, 2010 - MicroSeismic, Inc., a leading geophysical service company providing 3-D passive seismic imaging for energy exploration and production, today announced that it has completed installation of a Buried Array system in the Williston Basin's Sanish Field for Whiting Oil & Gas Corporation, the wholly-owned subsidiary of Whiting Petroleum Corporation.
This expansive Buried Array spans an area of more than 150 square miles in Mountrail County, North Dakota and uses more than 1200 geophone channels. The Buried Array will enable microseismic monitoring, mapping and analysis of the hydraulic fracturing operations for Whiting's Sanish Field development program. It will also permit Whiting to monitor the primary, secondary and tertiary activity, in a variety of reservoir conditions, for their Bakken and Three Forks Formation wells on a long-term basis.
Real-Time Monitoring Is Fracking's Newest Revolution, aiche.org, June 25, 2012.

MicroSeismic completes buried array in Williston Basin for Whiting Oil & Gas; Exploration and Production Magazine, March 10, 2010

Hydraulic fracturing and microseismic monitoring: UNDEERD and multiple Bakken operators, December, 2008

A life of Field Monitoring Array for the Sanish Field, North Dakota, wbpc, undated, abstract only;

For thoughts on this array, click here.

Miscellaneous notes posted since the original note:
The "microseismic array" story became more interesting when The Daily Mail referenced a larger array. But these may be two different "animals." The Daily Mail may be referencing a "seismic array," whereas the North Dakota story references a microseismic array.

"Frac Hits": from Bloomberg, April 29, 2017
After drilling 27 gas wells in North Louisiana in the first quarter, Range Resourcdes Corp shut in some production to avoid “frac hits,” or damage that can occur to an older shale well located next to a newer one.
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Simultaneous Hydraulic Fracturing Treatments in Adjacent Horizontal Wells

From a very interesting paper, geoconvention, 2009: Real-Time Microseismic Monitoring of Simultaneous Hydraulic Fracturing Treatments in Adjacent Horizontal Wells in the Woodford Shale.
Introduction:
The commercial success of horizontal wells drilled in shale-gas reservoirs depends upon the ability to initiate multiple parallel fractures, and/or the presence of complex networks of natural fractures that are connected by induced hydraulic fractures.
Production modeling of horizontal well completions shows that recovery might be improved if the distance between parallel hydraulic fractures can be reduced.
Simultaneous fracturing of two or more adjacent and parallel horizontal wells has been tested in the Barnett Shale to create hydraulic fracture networks more closely spaced than can be achieved from a single wellbore.
Positive results in comparison to wells completed individually were attributed to increased fracture complexity resulting from the interaction of hydraulic fractures initiated in parallel wells. Pressure response while fracturing and radioactive tracer surveys were the primary evaluation tools used. The two previously mentioned references contained an implicit assumption that rock mechanical properties were more or less constant along the length of the horizontal lateral. Evaluation of fracture stimulation treatments in the Barnett Shale that incorporated advanced open-hole logging measurements such as image logs, and borehole-based microseismic monitoring, showed that fracture geometry can be influenced greatly by changes in rock properties along the length of the lateral.
The implications of such heterogeneity cannot be ignored when transferring technology from the Barnett Shale to other gas-shale reservoirs. In this paper, we present the results of a microseismic monitoring camp aign undertaken as part of a drilling and completion program in the Woodford Shale of south-central Oklahoma that included both single-well and simultaneous fracturing treatments.
Two project areas, designated Eastern and Western were selected for live microseismic monitoring during fracturing operations. The project began with a single-well completion in May, 2007 in the Eastern project area. In April, 2008, a four-well simultaneous fracturing treatment was performed in the Western project area. The Eastern project area was finished in June, 2008 and included re-stimulation of the first well completed in May, 2007, a two-well simultaneous fracturing treatment, and the completion of a single well. All treatments were monitored with borehole-based microseismic measurement.
Real-time processing and display of microseismic event locations was provided to the engineering team re sponsible for the fracture stimulation treatments at the fracturing location.
Conclusion:

Evaluation of the production histories of wells discussed in this paper appears to show that simultaneous fracturing treatments do not necessarily increase well productivity when compared to conventional completions.
Also, where new wells have been drilled in proximity to existing wells there is potential for damage to the completed well by fluids introduced durin g the stimulation of the new well(s).
The benefits of simultaneous fracturing are most apparent when 3 or more wells are stimulated simultaneously.
In the western project area, the interior wells produce more gas when normalized for lateral length compared to the exterior wells. In the eastern project area, the A4 well, which was completed without simultaneous fracturing, has the highest sustained gas rate and cumulative production. The objective of using microseismic data was to assess the four-dimensional development of the induced fracture systems both in space and time.
Using real-time microseismic monitoring allows adjustments to the pumping schedule while the treatment s take place (i) to improve the effectively stimulated reservoir volume, (ii) to interpret unusual pressure responses, and (iii) to identify contact with potential geohazards.
Microseismic monitoring of the individual-well completions and simultaneous fracturing projects showed that substantive changes in fracture network geometry occurred along the laterals. The change in fracture geometry appears to be in response to structural complexity combined with lithological effects. An important implication of this study is that production improvements or cost savings might be achieved through better integration of surface seismic data, open-hole logs, directional drilling measurements, and borehole-based microseismic monitoring.
Completion engineers can take full advantage of the information available when designing stimulation treatments, and make changes to those treatments during pumping operations when needed. The benefits of this approach have been proven in many shale-gas reservoirs around the world.

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