The issue of seismic exploration is a component associated with urban gas leasing which causes much confusion to owners.  The logistics, low price offers, potential for damages and impact on subsequent leasing efforts should be understood and evaluated prior to accepting a check that may range from $5.00 - $25.00 an acre to allow access to your property by seismic companies.
 

MECHANICS OF SEISMIC EXPLORATION:

    Seismic exploration is premised on the application of a source of energy on the surface of the earth, while simultaneously picking up reflections of the seismic waves with listening devices placed in strategic locations.  The resulting data is read electronically to form a map of the subsurface rock formations.  Technology has evolved to allow computerization of the information generated to form two-, three- and even four-dimensional results (useful for time-lapse imaging). 

    The  "source" of energy applied at the surface of the ground can be via small dynamite charges placed in shallow surface holes, or more commonly in urban areas, via a "thumper" truck, which uses a large, heavy iron plate which is raised by a hoist and dropped from a height of several feet to impact (or "thump") the ground.  Other units employ vibrating plates to create a series of vibrations.

    A system of listening devices called "geophones" pick up the reflected seismic waves and feed the information into computerized programs.  

    The more receivers used, the better and more comprehensive the quality of the received data.  Most geophones are spaced in cabling that is run across the surface of the land, looking like large electrical cords.  Technology now exists for cableless systems that allow placement in dense areas where cabling would be problematic.
While 2-D seismic provides a single cross-section of the earth’s subsurface, along a fairly straight line, 3-D seismic depends on a grid placement of geophones.  As results are read, a multi-dimensional data set is displayed showing three dimensional images of the rock formations of interest.  This data can be manipulated electronically to evaluate and analyze minute details and dimensions.

    Seismic waves, as they reflect and bounce off rock layers of differing density and types, give geologists critical information necessary to identify rock layers, faults and natural fractures, and areas of uplifts, karsts and sink-holes.  Identification of these subsurface geologic details allows considered placement of lateral lines and drill sites to maximize productivity of planned wells.

SAFETY AND DAMAGE ISSUES:

    With the more widespread use of truck-mounted “thumper” and vibrating energy sources, the explosive dangers associated with dynamite charges are eliminated.  The logistics of laying out long geophone lines can still cause negative impacts to properties as can the potential for physical damage caused by the use of heavy equipment in urban areas.

    The mechanics of thumper trucks generally require that they not be used on paved surfaces because of the force of the impact which can break or disintegrate concrete or asphalt road surfaces. Crews laying out cables can crush landscape beds, break bushes or trees, or leave fences and gates open allowing pets or livestock to get out. 

    Shock waves emitted by the trucks can also panic or stress livestock and ribbon flags and trash left behind by seismic crews can harm livestock and native species through ingestion.  
Some reports of damages to foundations and buildings have been publicized when thumper trucks are used in close proximity to structures but setback restrictions incorporated in documents should minimize the possibility of such damages.

WHY SHOULD I ALLOW SEISMIC CREWS ACCESS TO MY PROPERTY?

    Much of the answer to this question depends on whether the one asking has an ownership interest in mineral development.  If minerals are not owned, the risks associated with seismic exploration, however small, are not worth the minimal per acre payment.    

    Timing of seismic exploration in relationship to leasing is also worth considering.  The presence of the gas-rich strata known as the Barnett Shale is undisputed through-out much of North Texas.  Seismic data is not used so much as to verify the presence of gas bearing formations as much as to allow proper placement of drill sites and horizontal lines to avoid subsurface problems and maximize well potential.  Most reputable drilling operators will require access to seismic data prior to drilling, although historic seismic information is available throughout much of southern Denton County.  

    After a lease has been finalized and the bonus money credited, allowing seismic analysis of the subsurface will improve the ability of the operator to plan and stage the drilling and fraccing process.  Agreeing to limited seismic testing at this stage, therefore, offers the potential to increase production on which a mineral owner's royalties will be based.

    Before that point, however, allowing seismic operations can have the same effect as laying down your card hand for your opponent to evaluate prior to bidding against you.  

    Seismic data is closely guarded by operators who often share results with each other.  Information is used pre-leasing to determine both value and selection of sites on which leases may be sought.  
Mineral owners without benefit of the results are at the mercy of operators in determining the reasonable value of their minerals. In some cases, operators who may otherwise have leased property and paid significant bonus rentals may withdraw offers completely after seismic testing reveals impediments so significant that the property is effectively condemned.  This is referred to within the industry as “seismic condemnation” and can eliminate lease offers.

    Regardless of when the decision is made to allow seismic testing, protective clauses for reasonable setbacks and requiring evidence of insurance should be part of the negotiation process prior to allowing seismic access.

    Understanding how and when seismic testing is effectively used is the best step in determining whether and when to agree to allow seismic crews access to your property.

    This article has been prepared by Virginia A. Moore, an attorney practicing in Flower Mound, TX.  It is intended to be general and informative in nature and does not constitute legal advice.   © LAW OFFICES OF VIRGINIA A. MOORE