4 – Announcing the Shaped Charge

Robert McLemore, a petroleum engineer who worked at Well Explosives, Inc., had to answer a question: How could he effectively inform the industry and potential clients that his company had shaped charges available for the oil field? He determined the answer would be articles published in well-known industry magazines. In these articles he could explain how shaped charges work, how his company had thoroughly tested these devices, and how shaped charges could increase the production of oil and gas.

Sharing Information

Convinced this approach would effectively transmit the message and generate business for his company, McLemore wrote an article for an issue of The Oil Weekly.¹ The title was straight to the point: “Formation Penetrating With Explosive Shaped Charges.”

The article began with an optimistic description of the benefits of the technology. Shaped charges would be “an agent for higher potentials and greater ultimate production.” Deep penetration into the formation by small shaped charges would “open channels which result in increased production.” McLemore then described how a shaped charge worked and included results of tests performed on steel targets and provided photographs. One photo displayed a 2-inch diameter by 3¼-inch long steel cylinder with a hole bored through its entire length from a shaped charge jet (Figure 1).

The article also recounted several successful field tests using shaped charges. According to McLemore, the shaped charges freed blockages in clogged, stripper-type wells, resulting in “a substantially increased productivity rate.” A key benefit stressed in his article was that the shaped charges would penetrate steel casing without damaging it and then create “fissures and breakage within the formation.” He concluded the article with predictions of potential uses for shaped charges, emphasizing increased production and economic benefits.

To add credence to his knowledge and enthusiasm for shaped charges, McLemore directed the readers to his patent on the device (U.S. Patent No. 2,543,814).² In this patent McLemore proposed swiveling shaped charges that would pass through small-diameter pipe or tubing.

Article Number Two

McLemore published a second article in the December 1946 issue of The Oil and Gas Journal.³ It contained several photographs of holes through steel casing and into cement that were made by shaped charge jets. Tables in the article displayed data showing the differences in penetration depths from shaped charges of various sizes with hard and soft-metal liners. The charges with hard metal liners (copper and steel) penetrated farther than those made with soft metal (aluminum and zinc). The article also offered positive predictions of shaped charge use, including the absence of damage to the casing or cement from the jets.

Ads and Papers

McLemore’s articles in two well-known industry magazines succeeded in introducing oilfield shaped charges to the world. He also placed ads (Figure 2) in these magazines and others.

McLemore then sought to disseminate the benefits of shaped charges to members of professional organizations. Such an effort required a different document, so he composed a technical paper for presentation at the Twenty-seventh Annual Meeting of the American Petroleum Institute in 1947.⁴

His technical paper supplied a thorough examination of shaped charge technology. The document provided substantial details on the collapse of the cone liner and the formation of the jet.

McLemore’s paper also introduced new terms such as “standoff distance” (the distance between the shaped charge and the target) and “carrots” (a.k.a. “slugs” — the liner material that followed the jet).

Challenges Remain

Challenges mentioned by McLemore in the paper included designing a charge that would be small enough to go inside small-diameter well casing and produce a jet that penetrated it without causing splitting. Additional goals for future research were a detonation process that caused no interference with nearby charges and a durable, re-usable carrier for the charges.

The paper also revealed an issue with the choice of the explosive for shaped charges. McLemore stated that Pentolite™, a commonly used explosive in military projectiles, was considered but quickly rejected. It had the unsatisfactory feature of a low melting point (165°F). In many wellbores the high temperatures caused the explosive to fume and dissipate.

A substitute explosive was found that could withstand a temperature of 325°F for 24 hours and a temperature of 350°F for 1 hour. McLemore did not state its composition or product name (after all, this was a very competitive market).

According to McLemore, his company’s tests had solved many potential problems, and their shaped charge products overcame significant challenges. This statement seemed to imply that most design work was complete. However, other companies and individuals were designing shaped charges, and some of these designs required creative approaches to overcome oilfield perforation issues.

References

1. McLemore, Robert H., “Formation Penetrating With Shaped Explosive Charges,” The Oil Weekly, July 8, 1946. p. 56.↑
2. Thompson, W. H., et al., Means and Method of Tilting Explosive Charges in Wells, U.S. Patent number 2,543,814. Filed December 30, 1946.↑
3. McLemore, Robert H., “Shaped Explosive Charges,” The Oil and Gas Journal, December 1946.↑
4. McLemore, Robert H., Application of the Shaped-Charge Process to Petroleum Production, Technical Paper at the 27th Annual Meeting of the American Petroleum Institute, November 1947.↑
5. Screen capture from website www.hometownbyhandlebar.com.↑

Join the Discussion!

• Do you have any knowledge or sources about other early articles or publications that helped introduce shaped charge technology to the oil and gas industry?
• Can you share any insights or historical details about competing shaped charge designs developed by other companies or individuals at the time?
• Have you come across any firsthand accounts or industry discussions from the late 1940s about how oil companies reacted to the introduction of shaped charge perforation?

I’d love to hear your perspective. Share your thoughts or answer a question in the comments below!