Proceedings, Indonesian Petroleum Association
Thirty-Second Annual Convention & Exhibition, May 2008
Mud Diapirs and Mud Volcanoes in Depressions of Java to Madura: Origins, Natures, and Implications to Petroleum System
Awang Harun Satyana*, Asnidar*
Mud diapir and mud volcano are piercement structures showing release of overpressured sediments piercing upward from subsurface to the Earth’s surface due to buoyancy and differential pressure. These structures occur in “elisional” basin mainly characterized by rapid deposition of thick young sediments, presences of fluid overpressures, under-compacted sediments, and petroleum generation; and recently compressed.
The Bogor-North Serayu-Kendeng-Madura Strait Zone was an axial depression of Java to MaduraIslands with elisional characteristics. The Mio-Pliocene and Pleistocene sediments were rapidly deposited into the depression and compressed since then due to the islands have been located frontal to the plate convergent boundary. Numerous mud diapirs and mud volcanoes are found along the zone.
We examined the origins and natures of mud diapirs and mud volcanoes found along the depression, they include : Ciuyah mud volcano (Kuningan, eastern West Java), North Serayu diapirs (northern Central Java), mud volcanoes of Bledug Kuwu, Bledung Kesongo, Bledug Kropak (to the south of Purwodadi, Central Java), mud diapir and mud volcano of Sangiran Dome (Central Java), LUSI (erupting mud volcano, Sidoarjo, East Java), Porong, Kalang Anyar, Pulungan (Sidoarjo), Gunung Anyar (Surabaya), Socah (Bangkalan, Madura), and submarine mud diapirs and mud volcanoes of the Madura Strait. The origins were basically same, relating to factors in elisional system. The surface morphologies of mud volcanoes include : swamp-like area, crater muddy lake, classic cone edifice, and collapsed synclinal depression. The development stages of the mud diapirs to mud volcanoes include stage-2 (pre-eruption –diapiric phase), stage-3 (syn-eruption), and stage-4 (post-eruption). These mud diapirs and mud volcanoes apparently have spatial and genetic relationship with petroleum. Oil and gas seeps and producing oil and gas fields share the same places with the mud diapirs and mud volcanoes of the Bogor-North Serayu-Kendeng-Madura Strait Zone. It is considered that here mud diapirism and mud volcanism have implied the petroleum systems, especially in : maturing the source rocks generating petroleum, forming structural dips and faults for petroleum migration and generating diapiric structural traps at shallow horizons. Worldwide cases show that diapirism and mud volcanism have close relationship to petroleum and here in Java to Madura we have the same case.