click here

Selasa, 09 Desember 2008

Debate Lumpur Sidoarjo

Case mud in Sidoarjo technically still fishing pro and contra. For example, underground blowout (UgBO) in the wells Banjarpanji-1, which is the cause of the accused (David 2007, and Tingay 2008), still in the form of a hypothetical controversial because the various data and facts to contradict.

In addition to this hypothetical need to be proven correct, there is still a hypothetical two more near, the mud volcano caused remobilisasi zone, high (overpressured zone) through the field tereaktifikasi fault that the increased movement by the earthquake and tektonik (Mazzini, 2007) and hypothetical Geothermal , The discharge superheated hydrothermal fluids bertemperatur and high pressure through the field rekahan (Sudarman 2007).

Tektonik increase in activity as a cause of the emergence of mud in Sidoarjo (Lusi) support the increased activity of Mount Merapi and Semeru three days after the Yogyakarta earthquake on 27 May 2006 and the accident results of drilling mud loss (loss circulation) in the wells Banjarpanji-1 about 10 minutes after the earthquake and the total circulation loss of 2 times after the aftershock. Thermal data recorded Moderate Resolution Imaging Spectrometer (MODIS) shows the increase in the activities of Mount Merapi and Semeru of 2-3 times, as discussed in the Harris and Ripepe Paper, 2007.

Mud volcano is not new in East Java, as we can see at Scone collapse structure (7km from Lusi), Kalang Anyar & Pulungan (Sedati, Sidoarjo), Mount Anyar (Campus UPN Surabaya), Bleduk Kuwu & Keradenan (Pretoria) , Wringin Anom / Pengangson (Lawrence), Semolowaru (Campus Unitomo, Surabaya), Dawar Blandong (Greystones), Sangiran (Central Java), Socah (Belfast, Madura). Mud volcano has been there since the days of old, even recorded in the Book of Pararaton, Fiber Sheena, Chronicle of the velocity, folklore Timun Mas (Satyana, 2007). Only the time of birth is associated with the drilling of wells as the cause.

After data is analyzed drilling wells, appeared in the wells UgBO not happen. The pressure in the well is too low to cause rekahan long rekahan arrest and has remained open so that the mud out. Sumurnya it, which is the easiest route (the path least Resistance) for the discharge of mud in the dead, not removing the mud, liquids and gases. Even since the beginning of Lusi mud have been issued with a very high velocity, as 50.000m3 or more than 300,000 bbl / day, the BOP (blowout preventer) in the open. Drilling activity can still be done, such as fishing, cementing and circulating, and others.

At the initial spurt, debit mud equivalent to a third of U.S. oil production, at the peak velocity exceeds Indonesia's oil production, a million barrels per day. The likelihood is very small for a well to remove the debit extreme, the required parameters such as flow and Reservoir permeability greater than 3,500 wells mD with a radius of 2,286 times (about 1.4 km diameter) and exposed in the formation kujung setebal 3,200 times. Simulation is done with debit formula radial flow Equation Darcy Law (Nawangsidi, 2007). As an illustration, permeability, the highest production wells in the formation kujung of 22.5 MD. So, to achieve the required parameters debit Lusi flow 140 times larger.

When first outburst occurred on 29 May 2006, performed well in the injectivity test to determine whether storm-related wells. After drilling mud dipompakan as much as 2 times, there are no signs of a decrease in pressure as the tire leak. The pressure to survive at 900 psi. Injectivity next test conducted on the following day before cementation with the injection pressure of 370 psi with a rate of 2.5 bbl / minute which also showed no relationship between the spray and wells.

Key to determine whether the formation is broken with the calculation of whether there have been UgBO that lead to high pressure that split the point on the formation terlemah. The calculation of the value of using the shut in casing pressure, fluid density, bottom hole pressure and leak-off test data. The calculation that must be using the data read in the wells and the facts that occurred in the field. From the calculations revealed that the formation is not broken.

One effort to investigate whether there is a relationship between the spray and the wells are snubbing time of the operation and re-entry well in the long sonan do with the temperature and logging. If there UgBO, formation will be broken at the point terlemah in the casing shoe and mud flows will be back in the chassis. However, the results of logging sonan not show the 'noise' as a rule if there is a flow Fluid behind the casing and there is no deviation of the temperature anomaly is expected if there have been UgBO.

If the storm associated with the wells and flow through the wells, several months after the storm should only hole wells that have not yet installed a large chassis as tergerus Fluid flow, which is very large. Theory is often expressed by groups UgBO, when Fluid flows from the formation kujung possibilities in the formation kalibeng clay, breaking the formation and bring the results gerusan mud. If so what happened, 'fish' in the hole that should have fallen, not because the hole squeezed again has become very large. In fact, during the snubbing operation at the end of June until the end of the re-entry operations in mid-August, 2006, 'fish' is not life, not fall, and remain in position when the first left.

Differences in opinion and interpretation is actually normal. However, because of concerns the intent of many people, how beautiful if bunker-bunker that contradict each other sitting together, to see the data and the fact that indeed happens, discuss, debate and thorough.

Unfortunately, it does not happen in their own country. Thus the Geological Society in London and the American Association of Petroleum hand movement (AAPG) in Cape Town that will be on the special session on Lusi arena as experts debate the world. When the victims continue to be resolved, concerning the emergence of the trigger spray Lusi need dituntaskan. On the forum held in a thorough debate and held in Indonesia?

By Bambang Istadi, Geolog and Petroleum Practitioners