In November 1990, an oil company based in Cameroon decided to remove two old wellheads and a signaling spar from a dry up field and for that called to the company I was working for. In those years the most commonly used method for this type of dismantling was explosives.
Of course, these kinds of products could not be used just like that by whoever showed up because placed in inexperienced hands; this tool could become extremely dangerous.
At that time, explosives engineers were not common within the company and I made part of the few supervisors who got all the necessary licenses required for the implementation of these stuffs. And so, this is why the CX operation services decided to send me to Douala to perform this job. The Night flight from Paris to Douala took place a few days later without problems and on arrival it was nice to find back this little warm and moist air which contrasted with the winter weather I had left a few hours earlier.
Going through the customs formalities was much more easier than in other African countries and once past , I was picked up by my colleague Henri BWABE a local commercial diver, a super nice and competent guy who a few years earlier had survived a helicopter crash where he did despite the dramatic situation managed to save several other workers from drowning.
As I had traveled all night, he took me first to the hotel so that I could take three or four hours of rest before starting the preparation of project.
Sharp at noon he was there again. We took a little lunch together at the hotel and at 0:2 p.m. we left to meet the 2 client representatives. They explained in detail the nature of the work and asked me to prepare a working procedure for the following days.
After that, we left for the local agency where a small desk and a telephone were placed at my disposal. The first part of my job was to get in touch with the local supplier of explosives, to see what kinds of products he had to sell.
In the past, I already had the opportunity to make dismantling works of submerged metal structures and therefore used a two-component liquid explosive with very high performance, but here I doubted that this explosive mixture was available.
I was right, here the choice of the products was fairly limited and I was therefore forced to use the product invented by a certain Mr. Alfred Nobel in 1867 that’s to say dynamite. Having received the technical characteristics of the selected explosive I began to calculate the quantity of product I would need to complete my severing work.
Following the informations I had received from our client, I knew that the two wellheads I had to severe were composed by a 30’’ outer casing plus a 10’’ and 7’’ internal casing with the inner spaces filled with concrete.
Thus knowing this plus a few other parameters, I decided that the best way the blow those tubes up would be to use an internal bulk charge.
At contrary, the signaling spar was made by a single tube and in this case I considered that it would be much easier to implement an external cutting charge around it.
To allow me to fill the purchase order I still had to calculate how much explosive I would use. This was made with the help of a formula that gave as results 55 kg of dynamite for each wellhead and 20 kg of that same stuff for the external charge.
It must be known that the purchase and implementation of explosives are in most of countries subject to a very strict regulation and of course it was the same here in Cameroon.
The requested working procedure had been written in a few hours and thus the only thing I had to do now was to wait to all the necessary clearance papers.
The swimming pool and the bar of the Ibis hotel was very welcoming, but staying all day there, very little for me, I preferred by far spend my days with my new buddy Henri, who was delighted to show me his town and the surrounding area.
A few days later, after having received all necessary permissions, I did let come my dive team that would be composed by José, Yves, André, three French divers assisted by my friend Henri and Jean, another Cameroonian diver.
November 30, we embark aboard the Crystal Fish a supply boat that was going to be our working support for this project. The day was devoted to mobilize our diving equipment and around 02:00 p.m. everything was secured and the only thing we were still expecting was the explosives.
They arrived under high military escort on the shot of the 04:00 p.m. and after a few mandatory signatures, were immediately transferred to the storage container where they were immediately locked for safekeeping.
05:00 p.m., we were now ready to leave the port of Douala and order was given to unberth the vessel.
The last mooring line was at the point to be dropped when all of a sudden a stowaway appeared on the afterdeck under the guise of a cute black and yellow snake that immediately went for hide under the diving container.
Seeing this, Henri our African colleague immediately gave order to the crew to close all the passageway doors to prevent the snake from entering into the boat where he would have been very hard to locate.
On our side, we tried very carefully to dislodge the monster from its location using a pike pole. Not easy to reach him, the snake was well hidden. Then after several minutes the frightened animal suddenly decided to move from under the container to one of the diving umbilical’s where he curled himself in.
For its part, the Captain began to get impatient because time began to count if we wouldn’t want to miss the tide and so the only thing left to do was to use drastic measures. The firefighters lance was implemented and finally thanks to the strong water flow the dangerous reptile was thrown overboard.
Phew, the last mooring line could now be dropped and our supply boat sail for the open sea.
The voyage was relaxing and finally after a dozen hours of night navigation, we arrived on the oilfield. Just the time to take a little breakfast and we could now start to deploy the working material.
As the aft deck of our boat was too short to hoist the blasted elements entirely on board it had been decided to tow them slowly on the bottom one by one to a deep water zone.
Therefore the first day was devoted to strap all the casings from the wellhead together so as to not lose pieces during the towing.
While a part of the crew was busy with these securing works, José and I could now start the assembly of the first bulk charge.
05:00 p.m., everything was ready. The wellhead was secured, the supply boat towing line installed and my first charge was locked in the container until tomorrow morning. I had just to make a radio call to the field manager to inform him of the situation and confirm that I had planned the firing at 08:00 a.m.
Next morning: standing up at dawn for everyone. The night had been very quiet and the sea was as flat as a mirror.
My first job was to go to the radio room and inform about the weather conditions. Perfect, no risk of thunderstorm was forecast for the next hours which meant that I could start the operation.
I immediately made another contact with the field manager to confirm the shot and also remind him that we were going to have a radio silence starting at 07:00 a.m. This let me then one hour to install my charge and connect my blasting circuit without risking a premature detonation due to radio frequency energy hazards.
07:30 a.m., everything was ready, the 55 kg dynamite were hanging correctly inside the central tubing about 3 m under the mud, and what was just left to do was to connect my two electric detonators to the detonating cord.
Yet, something began to intrigue me. When I started my loading job, the sea with the exception of our boat was absolutely deserted, and now half an hour later it was infested by little fishing boats. These had probably been informed by the bush tam-tam that a miraculous fishing party would take place in the morning.
What could I do, wait until they go, certainly not because now that they were here, for sure they would not go away. Result, I finished my electrical connection, and then climbed down the structure to jump into the zodiac in which José and Henri were surveying me.
Slowly, the zodiac set out towards the supply boat while I carefully unrolled the firing line.
During the preparation of this operation, I had calculated that the detonation of my explosive charge would produce an underwater shock wave that would be dangerous to a distance of approximately 570 meters and clearly a large number of pirogues were inside this danger zone. Besides this, as they had nothing else to do than wait, many fishermen were taking a nap lying in their boat with often their hands and feet dipping in water which was not safe at all.
Once on board, I asked the Captain to take the megaphone and inform them of the risks. No reaction, a new message was made in English and Pidgin, nothing, nada, niet, these bastards don't deign to move.
Of course for me it was impossible to shoot in these conditions. I therefore decided to break the radio silence to inform the field manager of the situation and told him that to disperse all these boats, we needed the assistance of the Cameroonian Navy and some of the speedboats that were working on the field.
The dissuasion task force arrived on site some twenty minutes later, but despite the navy injunctions, very few fishermen moved.
The rest of the pirogues were finally chased from the restricted zone with the help of the speedboats firefighting water guns.
And it was so that between all that confusion I had to choose the best moment to shoot the bulk charge.
As expected, the explosion made a low acoustic wave immediately followed by a huge water column about 20 meters height.
Then barely a few seconds later, there was the fantastic rush. All the canoes set off and surged towards the area where already dozens of fresh fish began to surface.
For us, the first part of the mission was completed. The wellhead was now lying down on the bottom waiting to be trailed to the drop zone.
The severing of the second and third structure went as well as the first one except that this time we had taken care to require the attendance of the deterrent force well in time to avoid any surprises.
A few days later, I was back in Douala with Yves and André who were due to return to France the same evening, while I had to stay ashore a few days more to prepare a new project.
It was the eve of the weekend and so I told myself that I would probably be quiet for two days and thus prepared myself to spend a pleasant evening.
Bad luck, because early in the evening, I received a phone call from the local office informing me that my colleague José who had remained at sea with another team of divers requested my urgent assistance.
Indeed, Désiré, a Cameroonian diver of his team had made a serious decompression accident. Immediately, with the assistance of the local agency manager we tried to persuade the oilfield manager, to charter a helicopter to bring me the barge.
He was a bit reluctant because night flights were not allowed on the field but finally after a few minutes of discussion and given the seriousness of the situation, he nodded and gave us the green light.
Immediately, we made a new phone call to the heliport to inform them of the situation, but new problem.
As night flights were not planned, there was no pilot on stand-by and to make things even worse, most of them were busy partying and had already abused the bottle which was not very reassuring to flight.
Result, and probably to play it safe, it were two half sober pilot’s that we saw arrive at the heliport and who a bit latter invited us to take place in the helicopter.
Indeed, although Yves and André had to fly in the evening, I had asked them to accompany me to the barge because having heard about the gravity of the accident; I feared that the therapy might be long with quite a lot to do. In addition, Yves Langouet was also a qualified life support technician which could given the situation be very helpful.
Once installed, the pilots began the checklist, and at 09.00 p.m. precise the chopper took off.
Half an hour later the Bos 300 was in sight and shortly after the helicopter landed safely.
On the barge, José had in accordance with the encountered symptoms, begun a therapeutic CX 30 table. Although he had only made a short dive at 23 meters our poor Cameroonian diver had indeed developed a neurological problem right out of the water and sank into unconsciousness shortly after.
No chance for him either, the client had sent the dive team on a site located away from the barge where the DDC was installed and therefore our unfortunate victim had lost nearly an hour before he could be recompress at 30 meters.
Désiré regained consciousness in the recompression chamber but unfortunately had paraplegia of the lower limbs.
Once there, we relieved our colleague so that he could relax a bit from this stressfully situation he was on since a few hours.
The therapeutic treatment lasted a few more hours during which the present divers took turns alternately to assist the unfortunate diver.
At the end of the treatment, Désiré was again able to stand upright, but with a lot of difficulty. Meanwhile, on my side I had already been in radio contact on several occasions with our doctor in Marseille to keep him abreast of the situation. In the light of what I told him, he advised me to consolidate the treatment by a series of additional recompressions spread over the week, but as there was no therapeutic chamber in Douala, I was sentenced to spend the week on the barge assisted by my colleague José.
The various recompressions still improved slightly the general condition of our African colleague, but unfortunately he still had a urinary retention problem and loss of balance was still frequent. After the recompression treament, Désiré was transferred to a hospital in Douala where he stayed for another few weeks.
As for my colleague Jose and I our job in Cameroun was now nearly terminate and to thank us we were both invited to a dining party by our agency Manager before returning to home.
A few days later, time had come to return to Europe.
Our buddy Henri accompanied us to the airport to say us good-bye.
It was the last time that I saw him because he unfortunately disappeared while diving in scuba a few years later.
Conclusion: When your hour is there, it's there.