This week Oily Stuff continues it's stroll thru the annals of homo sapient induced errors that has led to some rather astonishing oilfield events over the years. Previously we have been in Turkmenistan, Mexico and Namibia; this week we find ourselves in Indonesia.
On 3 March 2006, an Indonesian oil company named PT Lapindo Brantas spudded its Banjar-Panji No. 1 well in the district of Sidojara in East Java. Onshore Java is oily, very gassy country but unfortunately its existing fields and hydrocarbon zones are tucked in between numerous, over-pressured zones of volcanic ruble and geothermal flows in the subsurface. Its tough sledding for the best of drilling engineers. The proposed TD of the BJP-1 well was Miocene carbonates associated with reef mounds located about 9,000 feet deep.
The BJP-1 well was an offset to the Porong-1 well located about 4 miles away. The Porong well found non-commercial hydrocarbons in an anomalous looking reef feature, but important pore pressure and frac gradient data was gleaned from the drilling of the Porong well that was, unfortunately, overlooked in the BJP-1 well.
The BJP-1 well immediately encountered over-pressured clastics at shallow depths and associated drilling problems
caused several key casing points to occur much shallower than necessary. 16 inch casing set below 20 inch casing in the well was not cemented very well, several leak off tests (LOT) failed and that string had to be remedially squeezed, twice. Below a string of 13 3/8ths, continued drilling problems actually led to two further proposed casing points being missed entirely. Over 5,200 feet of open hole existed below the 13 3/8ths casing shoe and 2,000 feet of known, over-pressured carbonate pay was drilled underbalanced, with no protective casing string above it. Late in May of 2006 at a depth of 8,800 feet, the well kicked, the BOPS were closed and several large volumes of mud were pumped to try and kill the well. Its clear, at least to this dumb roughneck, that pump-in pressures exceeded frac gradients downhole and that in turn caused stress related faulting in the subsurface, or reactivated an existing fault, and two days later an obvious underground blowout underway worked its way to the surface about 300 feet away from the well. Very hot water from the carbonate pay zone mixed with clays in the openhole section below the 13 3/8ths casing shoe... and the Lapindo mud volcano was born, nicknamed "Lusi," for short.
Brantas quickly abandoned ship. It cut stuck drill pipe, set some cursory cement plugs, rigged down and moved the hell out as fast as it could get gone. Both of its working interest partners, including Santos, LTD of Australia, wiggled out of the mess somehow, and over ensuing months things went from bad to worse. At one point Lusi was reported to be producing an estimated 1,000,000 barrels of mud per day. Ultimately 13 people were killed and over 60,000 people were displaced from their homes from mud flow that covered many square miles.
The operator of the BJP-1 well blamed an earthquake that happened about the same time it was taking a kick at TD and mud started bubbling up out of the ground near its well. The debate as to whether this was a man-made mess or simply Mother Nature doing Her thing rages on. Many really good papers have been written about the Lusi mud volcano but probably nobody knows it all better than an Australian geologist named, Mark Tingay, and he has an excellent, three-part series of this event on his blog, Critically Stressed. It is very interesting reading and I highly recommend it.
In 2017 the Lusi mud volcano pooped out for a brief time but then urped again and the latest from East Java is that it is slowing down a good bit, after 12 years, but still bubbling.
Shit happens, as
we say quite often in the oilfield, but this was a real doozy.