GeoScienceWorld

50 Years of Geophysical Ideas

By W. Harry Mayne

Abstract

“This booklet expands on the interpretation traps listed in SEG's popular monograph Pitfalls in Seismic Interpretation. Nontechnical and mental pitfalls are outlined in the sections on velocity, geometry, recording and processing, and stratigraphic traps.”

  1. Page 1
    Abstract

    In the spring of 1935,I graduated with simultaneous degrees, a bachelor’s and master’s in electrical engineering, from the University of Texas. I entered the university as a member of the class of ’34 but deferred obtaining mybachelor’s degree in order to preserve my athletic eligibility. By successfully juggling undergraduate and graduate courses, I still managed to obtain my master’s in a normal time frame and enjoyed the rare academic distinction of receiving two degrees on the same day.

    This turned out to be a good decision athletically but a poor one economically. Many of my colleagues in the class of ’34 went on to distinguished careers with General Electric, Westinghouse, Bell Telephone and a number of power and light companies. I expected to follow in their footsteps; but a severe downturn in business between the ’34 and ’35 graduations made the latter a very poor time for newly degreed engineers to enter the job market. The companies did not recruit on college campuses in 1935, and, at the suggestion of the head of the electrical engineering department, I wrote to a number of electrical companies and to an obscure (at least to me) geophysical contracting firm – Petty Geophysical Engineering Company, headquartered in San Antonio, Texas.

    The letters to the electrical companies yielded nothing. I arranged some interviews in Houston which were equally unproductive. I was getting desperate when, totally unexpectedly, I received a wire from Mr. O. Scott Petty. He was in Oklahoma City and wanted to know if we could meet.

  2. Page 20
    Abstract

    The World War II years were somewhat traumatic for the industry because of personnel disruptions due to military service and shortages of strategic materials and equipment. The industry as a whole wasstill in a period of consolidation; the major topics of interest were perfection of the instrumentation and better understanding of the underlying principles. The only personal contact I had with an innovative concept during this time occurred in the fall of 1943 when Petty was contracted to work along the Florida Keys.After working for a considerable period on Big Pine Key (the largest land mass in the chain), we decided to shoot a line ofjump correlation spreads – even in the absence of good data – from the upper end (Key Largo) adjacent the Florida mainland all the way to Key West, hopping from key to key along the extent of the entire chain. When this was completed, the results were sufficiently encouraging to cause us to prepare boats and devise methods of exploring in the water surrounding the Keys.

    About 1942, a number of oil companies and the major geophysical contractors entered into a business arrangement known as the Seismic Immunities Group. This resulted in a series of two-year agreements whereby all parties granted royalty-free licenses under their patents to all other parties. In case of withdrawal at the termination of a two-year term, any patent applications during the subsequent two years would also be covered.

    The membership did indeed change over the years, with some companies dropping out and others

  3. Page 29
    Abstract

    During the period 1945-52, the geophysical industry underwent a tremendous expansion. (In fact, the 1952 peak would not be attained again for 30 years.) I do not have any clear recollection that I noticed this extraordinary growth. I apparently was so preoccupied with my continuing seismic R&D and the work on aviation medicine that Iwas not aware of the state of the industry until the good times had passed and we had begun one of our all-too-regular business downturns.

    But apparently others at Petty were sensitive to the highly competitive nature of the geophysical market, and they mandated an intensive research effort by the company. At least two results of this research had profound impact on the industry: J.0. Parr’s invention of weighted source and geophone arrays, and my conception of the common reflection point method. (The Patent Office was notoriously slow in processing applications at that time, and we did not receive patents for these ideas until the mid-50s – Parr’s in 1955 and mine in 1956.)

    The weighted arrays could be performed with contemporary equipment, so this idea was exploited immediately after the patent application was filed. Petty actively campaigned for the use of this technique throughout the decade. By contrast, the CRP method was just an interesting theory at that time because the technology needed for its implementation did not exist.

    Petty had 31 crews in the field in the summer of 1952, the company’s zenith in crew activity. There were 27 seismic crews (23 working in the US, two

  4. Page 38
    Abstract

    The cyclic nature of exploration makes it prudent for geophysically oriented companies to diversify, and Petty initiated efforts toward this goal in the mid-1950s. They were largely unsuccessful until about 1960 when we became acquainted with the Defense Systems Division of General Electric. This association resulted in Petty becoming a member of the GE team which bid on the ill-fated Mohole project in 1961. (See Geophysics in the Affairs of Man by Bates, Rice and Gaskell for a full account.)

    We did participate in Project Gnome, one of the Plowshare series of atomic experiments. We occupied a site on the Llano Uplift in central Texas and recorded excellent first arrivals from a five kiloton explosion near Tatum, New Mexico (300 + km away). Special geophones with a natural frequency of one Hz were used with very low-frequency amplifiers. The results were recognized as among the best obtained by any commercial operator. General Electric designed and built the special equipment required, and we provided the personnel and field support.

    We also completed, as a subcontractor to General Electric, a substantial project for the Air Force associated with ballistic missile defense.

    The previously mentioned experimental work for Pure Oil so convinced J. Lee Davis of the effectiveness of the CRP method the he decided Pure should have its own processing center. He had also developed some very strong (and correct) ideas about how CRP could best be processed, but again, no contemporary machine had the necessary specifications.

    After defining the general requirements for the machine, Davis

  5. Page 46
    Abstract

    The years 1970-72 were not, aside from the bubble-reducing air gun, highly productive for me from a technical standpoint. These were times of intensive development and utilization of “direct” hydrocarbon indicators. Since these were not in my area of expertise, I was mostly involved in extensive marketing efforts–work that was essential in assuring that our expensive investments (two marine vessels and the computer center) did not sit idle for prolonged periods. Cliff Ray, Fred Barr and I did conceive one excellent idea in early 1972, a process that is now referred to as signature deconvolution or wavelet processing, but a patent search revealed that someone else had anticipated us. Early 1972 was also the time that Petty beganvibroseis operations; however, we provided only minimal technical support because the client insisted on calling all the shots.

    The Pettys had received and discussed many overtures for the purchase of the company over the years, but nothing had ever materialized. That changed in 1973 when two engineers in Rockwell International, J.E. Franklin and Sam Urcis, conceived the idea of a total service exploration company. Their interest had been sparked by the work of Rockwell’s aerospace division in remote sensing. They wanted to incorporate this new techno1ogywith the traditional geophysical techniques in the search for terrestrial resources. A financial support group consisting of Rockwell, Aetna Life and Casualty Company and a consortium of private investors was formed to underwrite the venture.

    Geosource International, Inc. started business in 1973 by purchasing Mandrel Industries from Ampex Corporation. By this time

  6. Page 54
    Abstract

    When Loughnane first described this latest assignment, he asked what my intentions would be when I reached the normal retirement age. He was delighted when I said I wanted to keep working. He replied that this was the answer he was hoping for; so in 1978 at age 65, I was given a choice: I could continue as a regular employee or become an exclusive consultant. I chose the latter.

    Loughnane arranged a surprise birthday party to commemorate this change in status. It was the most memorable event of my career. Several hundred friends from all over the country were invited to a delightful party at the Westin Galleria Hotel. A huge banner proclaimed, “Happy 65th Birthday, Harry!” After the inevitable watch and other presentations were made, this banner was removed and another exposed which read, “Now get back to work.”

    Loughnane died in March 1979 in the crash of his personal plane. A very short time later I learned that I was to receive the William Smith Medal. I feel certain that had Loughnane been alive he would have taken as much pride in this honor as I did. This medal is awarded annually by the Geological Society of London for special contributions to practical geology and related sciences. It is named after an early English geologist who is credited with originating the science of stratigraphy.

    John D. Platt became Geosource’s new president in mid-1979, about two months after Loughnane’s untimely death. His ideas on organizational operations were somewhat different from his predecessor’s

  7. Page 63
    Abstract

    The first issue of The Geophysical Directory was published in 1946. It consisted of twopages which listed seismograph, gravity meter, torsion balance and magnetometer contractors only.

    A listing of instrument makers was not included until 1947 (the second issue), even though a number of such companies had by then existed for some years. Those companies listed in the 1947 issue which I would classifyas the pioneers in the manufacture and sale of complete seismic systems were Century Geophysical Corporation, Electro-Technical Labs (ETL), Engineering Laboratories, Inc. (ELI), Heiland Research Corporation, Houston Technical Laboratory (HTL), Southwestern Industrial Electronic Company (SIE) and Technical Instrument Company (TICO).

    Coleman Instrument Company, Hale Instrument Company, Hathaway Instrument Company, Ruska Instrument Company and S.A. Scherbatskoywere early suppliers of various individual components.

    A number of early geophysical contractors – such as Petty, Western and Seismic Exploration, Inc. – maintained in-house instrument laboratories which designed and built proprietary equipment that was not offered for sale to others.

    Seismograph Service Company (SSC), Century Geophysical, United Geophysical, and later National Geophysical and Midwestern Geophysical started out by building complete seismic systems for their own use but then later offered these systems for sale to the industry with varying degrees of success.

    So many other companies have made contributions to the evolution of seismic instrumentation that it would be an impossible task to even list (much less detail the histories) of all. Consequently, I have chosen only a few of the above for more complete treatment. Selection was made either because of close personal association or because

  8. Page 77
    Abstract

    When I majored in electrical engineering at the University of Texas during the early to mid-1930s, there was a distinct separation of disciplines. However, I did go over to the Physics Department in the summer of 1934 to take a course in vacuum tubes. That’s where I met Lucian LaCoste. I’m sure that at that time neither of us knew anything about geophysics, let alone planned to make it a career. Both of us, of course, became geophysicists quite soon afterward and have remained active to the present. Our experience was not at all uncommon for that period. Very few geophysicists knew anything about it until they suddenly, and quite unexpectedly, found themselves in the business. It is a tribute to both the challenge and rewards of exploration geophysics that many, if not most, of the best remained in the industry throughout their entire careers.

    In 1935, shortly after Petty had put together the crew that was going to work in Cuba, we received word that the contract would be delayed because of political problems on the island. Cuba was experiencing one of its frequent revolutions – Batista was being overthrown (for the first time). We found out just before Christmas that things were going to be politically stable. We scheduled a January First sailing out of New Orleans and enjoyed a festive NewYear’s Eve on Canal Street, with the celebration continuing the next day. Everyone on the vessel (a combination passenger and fruit boat) was in the dining room that

  9. Page 85
    Abstract

    Petty was one of the cofounders and the prime mover in Petty Geophysical Engineering Company from its inception in 1926 until it was sold to Geosource in 1973. His father (Van A.) and his two brothers (Van A., Jr. and Dabney E.) assisted in the founding and development of the company.

    Petty received degrees in civil engineering from the University of Texas. The influence of his educational background and training is apparent in some of his early geophone designs. He later became, by self-education, proficient in the emerging science of vacuum tube electronics. Petty was fortunate early on to be able to hire such pioneer electronics experts as W. Lee Moore, W.L. Crawford, Arthur F. Hasbrook, C.D. Chamberlain and Robert Valentine. All of them contributed to the foundation of knowledge and technology that was available when I entered the business.

    O. S. Petty is the ultimate perfectionist and always insisted on trying to be the best. He was scrupulously ethical and never tried to promise clients more than he believed he could deliver. He is a very great and kind gentleman who has earned many honors, including Honorary and Founding Membership in SEG.

    Another Petty company pioneer who came into geophysics via civil engineering was P.J. Rudolph. He served as party chief, supervisor, general manager and president of Petty. A smallish and somewhat birdlike man, he was alwayskind and soft-spoken. He soon developed a reputation as one of the “superstars” of seismic interpretation, which he retained until retirement.

    Crawford joined Petty after studying

  10. Page 93
    Abstract

    Sometime in late 1949 or early 1950, I was involved in a crew startup in south Texas. This prospect was in a large area which was notorious for poor data; not surprisingly, the job proved to be exceptionally difficult.

    The difficulty was associated with a massive surface layer of caliche which blanketed the area. It was thought that this material was responsible for the horrendous, high-velocity reverberations which masked the desired reflections. The problems were compounded by the fact that the objective of the survey was to map a suspected series of small faults. It soon became apparent that geophone arrays which would be long enough to provide useful attenuation of the surface waveswould also cause unacceptable “smearing” of the subsurface and obscure the postulated faulting. As a result, the survey proceeded with a far-less-than-optimum compromise.

    Sometime after I returned to San Antonio, I was still wondering how this problem could be resolved. I needed a very long array to attenuate the noise, yet each point of the array needed to represent the same reflection point of the subsurface. For a non-dipping reflector, this meant that the source and a receiving station would have to move the same distance–in opposite directions – from the reflection (or mid-) point.

    Thus, if such a common reflection point array could be formed from a series of such source/receiver pairs, there would be no limit to the length (and attenuation of high-velocity noise) attainable.

    One problem still remained. The reflections had different traveltimes on each pair of sources and receivers,

Purchase Chapters

Recommended Reading