Stuck pipe is a common worldwide drilling problem in terms of time and financial cost. It causes significant increases in non-productive time and losses of millions of dollars each year in the petroleum industry. When the drill string is no longer free to move up, down, or rotate as desired, the drill pipe is stuck. Sticking can occur while drilling, making a connection, logging, testing or during any kind of operation which involves leaving the equipment in the hole.
In other words, the drill string is stuck when the static force necessary to make it move exceeds the capabilities of the rig or the tensile strength of the drill pipes. Stuck pipe can result in breaking apart of the drill string in the hole, thus loosing tools in the hole that requires time and cost to perform fishing job, of course if it works. The results of a stuck pipe are very costly and include:
A) Lost drilling time while freeing the pipe.
B) Time and cost of fishing: trying to pull out of the hole the broken part of the BHA.
C) Abandon the tool in the hole it is very difficult or expensive to remove it.
Generally stuck pipe problems are divided into two categories: mechanical sticking and differential sticking. Mechanical sticking usually occurs when the drill string is moving and is caused by a physical obstruction or restriction. Mechanical sticking can be classified into two major subgroups: a) Hole pack-off and bridges; stuck pipe which are related to wellbore instability or settled cuttings are in this category and b) wellbore geometry interferences; this refers to stuck pipe which are related to the condition of wellbore geometry such as key seats or an under-gage hole.
Commonly, differential sticking occurs when the drill string or tool is stationary(or sometimes when it is moving very slowly). Many oil and gas reservoirs are mature and becoming increasingly depleted of hydrocarbons, which increases the risk involved with the stuck pipe. This is due to the fact that decreasing pore pressure increases the chance of stuck pipe. Therefore, the risk of differentially stuck pipe increases when drilling depleted reservoirs and avoids when drilling underbalanced. It should always be considered the probability of freeing stuck pipe successfully diminishes rapidly with time.
S. R. Shadizadeh, F. Karimi, M. Zoveidavianpoor; "Drilling Stuck Pipe Prediction in Iranian Oil Fields:An Artificial Neural Network Approach"; Iranian Journal of Chemical Engineering Vol. 7, No. 4 (Autumn), 2010, IAChE
A. M. Paiaman and B. D. Al-Anazi; "Feasibility of decreasing pipe sticking
probability using nanoparticles"; NAFTA 60 (12) 645-647 (2009)
Nediljka Gaurina-Medjimurec and Borivoje Pasic; "Risk Due to Pipe Sticking"
Ali Seyyedalangi- M.Sc in Drilling Engineering
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Headline crude prices for the week beginning 12 November 2018 – Brent: US$71/b; WTI: US$60/b
Headlines of the week
It seems to have been a topic that has been discussed for years, but a decision could finally be made. The Philippines has short-listed three different groups who are in the running to build the country’s first LNG import terminal, whittling them down from an initial 18 that submitted project proposals. The final three consist of the Philippines National Oil Company (PNOC), a joint venture between Tokyo Gas and domestic firm First Gen Corp and China’s CNOOC. The Philippines hopes to choose the final group by the end of November – an optimistic decision that belies that many, many complications that have come before.
First of all, the make-up of only one of the groups has been finalised. A local partner is a requirement for this project; CNOOC has yet to officially tie-up, although it has been talking to Manila-based Phoenix Petroleum, while state oil firm PNOC does not have a (deep-pocketed) partner yet. Firms including Chevron, Dubai’s Lloyds Energy Group and Japan’s JERA have reportedly contacted PNOC to express their interest, but a month before the Philippines wants to make a decision, its own home-grown hero hasn’t yet got its ducks lined up in a row.
And time is of essence. The once giant Malampaya gas field is running out of resources. Supplying piped natural gas to three power plants that feeds some 45% of Luzon’s electricity requirements, the Shell-operated field is expected to be completely depleted by 2024. With the country aiming to move away from burning coal or (imported) gasoil for power, gas is needed to replace gas. Even though the Philippines is pushing for a bilateral agreement with China to pave to way for joint exploration activities in disputed areas of the South China Sea – to the consternation of its citizens – any discovery in the Palawan basin or Scarborough Shoal will be years from commercialisation.
So LNG is the answer. And LNG has been the answer since 2008, when the need for an LNG import terminal was first identified. And it is not like no projects have been proposed – Australia’s Energy World Corp (EWC) has been wanting to build an LNG receiving terminal and power station in the Quezon province near Manila for years, but the project has been described as ‘trapped in a bureaucratic quagmire’ due to hurdles from various government agencies, or stymied by groups with competing interests.
PNOC itself has been wanting to build its own terminal in Batangas, within range of existing gas and power transmission facilities currently drawing Malampaya gas. But, just like Pertamina in Indonesia, it is cash-strapped and unable to drive the project on its own, hence the requirement for a partner/s. First Gen Corp and Phoenix Petroleum are both private players, with First Gen already operating four of the country’s five gas-fired plants while Phoenix Petroleum has close ties with CNOOC Gas.
Many announcements have been made and gone, but with this shortlist of three groups, it does finally look like the Philippines will be able to get its LNG ambitions of the ground. And it is thinking even bigger; wanting the terminal to become a LNG trading hub for the region – capitalising on the existing habit of ship-to-ship transfers of LNG cargoes into smaller parcels in the Philippine waters for delivery into southern China – challenging existing ambitions in Japan, South Korea and Singapore. But perhaps that is getting a bit ahead of themselves. Getting a project – any LNG project – off the ground is the first priority. And the rest can come after that.
Other Proposed LNG Projects In The Philippines: