Crisis at Titas Gas Field |
Blowout barely averted at enormous gas loss
Wild release of gas to continue as it is not possible to fix well in month; authorities' lax attitude to handle gas leakage problem criticised
The 38-year old third well of the country's biggest gas provider Titas Gas Field in Brahmanbaria yesterday went totally out of control with an uncontrolled release of gas at the rate of 15 to 18 million cubic feet a day (mmcfd), highly placed sources said.
Bapex, which was inappropriately assigned by the authorities last month to fix the uncontrolled leakage of gas, barely saved the field from a devastating blow out by burning this gas. Earlier, Bapex was trying to remove anomalies in this well.
"This gas will continue to burn for at least another month to 45 days even if we are able to enforce the fastest remedial measure," noted a well-placed source.
Fifteen other wells of this field are however still in operation.
"What a wastage! This could have been easily avoided had the authorities paid proper attention to early warnings in the media and deployed a world class operator to solve the field's problems," the source said.
The Daily Star has been reporting on an impending disaster in the field since early February.
This development prompted the energy ministry to hold an emergency meeting yesterday morning with the owner of the field-- Bangladesh Gas Field Company Ltd (BGFCL)-- Petrobangla, Bapex and all multinational oil companies working in the country.
The oil companies suggested installation of a "coil tubing" at the affected well to bring it under control. This technology is available with the oil companies and it might take between one month and 45 days to install it successfully.
The energy ministry instantly decided on this solution.
"It is also important that we now hire, on an urgent basis, an international consultant to handle this situation as per a previous suggestion of the BGFCL. The people in charge should start surfing the Internet right away to find out which companies are most experienced in handling disastrous situations like this," the source pointed out.
With high officials from Petrobangla and Bapex present at the site Friday night, the Bapex started its action to kill the third well where gas pressure anomalies indicated deep structural problems.
"To stop the gas flow from this well, technicians first injected a heavy chemical called Brine Solution. This chemical is supposed to balance the well pressure so that the well can be gradually killed. But the injection left no impact. The chemical seemed to be spreading inside the well and into the formation of the gas field," one source pointed out.
"As a secondary measure, Bapex then started pumping in heavy mud. Instead of controlling the pressure, this measure increased gas pressure immensely and soon it started gushing out at various points in full force. And this was a situation closest to a blow out."
The source went on, "In such an uncontrolled situation, the best Bapex could do is to put a flame in the uncontrolled gas and let it burn freely. This method is called bleeding the gas. This way we avert a blow out or further damage to the field's formation.
Sparse gas leakage from various points of the ground in Brahmanbaria had been noticed for the last three to five years. But since the last dry season, this phenomenon has become alarming. Local villagers and farmers had told The Daily Star in February that gas was leaking through more than 3,000 big holes-- including some 30-foot diameter ones-- in IRRI paddy fields, water bodies and the Titas river. The emitting gases through some of the holes were burning with high flames.
During that time, eight local and foreign experts reviewed Titas Gas Field's situation and data, warned of an impending disaster and strongly recommended hiring an international consultant to advise the government what actions should be taken. Later, the site was visited by experts from Chevron and Thai Petroleum company PTT, who stressed averting a disaster as soon as possible.
But the caretaker government apparently did not pursue the matter with utmost seriousness and left the matter to be dealt with by people lacking capability to do so, alleged an expert.
In late February, the BGFCL board discussed the matter and relied on the suggestions of two experts in its board-- a retired Petrobangla official and a Buet teacher. Both the experts suggested that Bapex was enough to do the job and that hiring foreign consultant would be unnecessarily costly.
Without reviewing Bapex's capabilities and experience, the BGFCL board assigned Bapex to do the job in late February. The Bapex board, headed by the energy secretary, also accepted the assignment without understanding its own strength. Bapex mobilsed its rig to the site early last month.
Meanwhile, high officials warned Bapex and BGFCL officials not to talk to the press about the gas field's leakage in a bid to give the public an impression that everything was under control.
With the initial impression of the problem, Bapex wanted to initiate a work over procedure in Well Number-10, which was built in 1988 using low quality cement.
But a senior Bapex official saw different signs in the gas field's data and he pointed out that the main source of the problem was with Well Number-3. This well was built by Shell Oil in the late sixties. When his observation was ignored, he wrote to Petrobangla and the energy secretary for their attention. In a follow up meeting, he presented his data and argument, and everyone was convinced that the culprit was the third well.
"It goes to show that the whole operation was not well planned because those who made decisions did not understand the gravity of the situation," noted an official.
Titas field produces 400 mmcfd gas as against the country's total gas demand for 1,500 mmcfd. Discovered in the early sixties by Shell Oil, Titas was estimated to have a gas reserve of 5.12 trillion cubic feet (after four decades it now has 2.78 tcf).
TROUBLE AT THE THIRD WELL
Shell Oil built the third well in 1969. Shell's original well design contained a basic flaw, which coupled with lack of monitoring of the well's health by the BGFCL, led to the present situation, sources pointed out.
"In a traditional well design, we use several smaller to larger casings to contain gas pressure and to ensure safety and control. Traditional designs start with a 30 inch casing, inside which we place a 20 inch casing, then a 13.38 inch one, then 9 point five by eight inch one, then 7.5 inch and finally 4.5 inch (total six casings)," said a geological expert.
Well Number-3 was built with five casings and it did not have the 9 point five by eight inch casing. "This means they installed the 7.5 inch casing inside the 13.38 casing. There has been a wide gap between these two casings and this served us for 38 years," he added.
Gas is supposed to flow through the 4.5 inch production tubing inside these casings only.
Again, the BGFCL should have strictly enforced monitoring routines using bottom hole pressure measuring device. It turned out in recent monitoring that gas was flowing through three casings --from the 4.5 inch to the 13.38 inch ones-- with equal pressure. "This indicates that there must be some cracks in these casings," the geologist pointed out.
But these conclusions were drawn only recently, just because a Bapex official noticed the readings of all the wells of Titas.
"This is most unfortunate that although there had been adequate warnings, we have not treated Titas field seriously. This field is still the country's energy lifeline," he observed.