The LUSI mud volcano triggering controversy: Was it caused by drilling?

Following the Yogyakarta earthquake on May 27th, 2006, the subsequent eruption of a mud volcano has been closely observed and analyzed by the geological community. The mud volcano, known as LUSI, began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia. LUSI offers a unique opportunity to study the genesis and development of a mud volcano. For the first time, this paper presents all raw and interpreted drilling data, so any interested party can perform their own assessment. Our study suggests that LUSI mud volcano was a naturally occurring mud volcano in an area prone for its mud volcanism. Pressure analysis done on the Banjarpanji well shows that the pressure exerted at the well is lower than the fracture pressure at the last casing shoe, and suggests that the well was intact and did not suffer an underground blowout. This is further supported by evidence and observation made during drilling (such as circulation was done on an open BOP) and subsequent relief wells (Sonan and temperature log runs). This study offers a different alternative to earlier hypothesis that events at the Banjarpanji well were the trigger for the LUSI mud volcano. More work is needed by the scientific community to study the sequence of events in order to explain and clarify the real trigger of LUSI.