Manila Bay 1, 1A, 1A Sidetrack; Success Against All Odds
Edward F. Durkee and Freddie G. Rillera
The discovery of gas in Manila Bay is one of the more significant exploration discoveries in the Western Pacific in recent years. Within the Philippine Archipelago there is no better geographic or economic location to discover gas than at Manila Bay.
Geologically, the well has proven that new concepts applied to old areas, in opposition to past beliefs and dogmas is still a valid way to find hydrocarbons. This is especially true re the western margin of the Central Valley of Luzon. New Venture reviewers (more than 100) were generally negative about the possibility of limestone objectives at this setting. The operators eventually drilled the prospect by themselves.
The Manila Bay discovery well is on a large basement uplift with more than 2000 feet of vertical closure and 8,000 acres of areal closure at Miocene levels. The geological surprise was that the well drilled through a Pliocene Limestone (700 feet) charged with gas. An estimated in place resource of up to 2 TCF is possible. This is economically very significant for the Philippines as it is only 30 km from downtown Manila, a city of some 10 million people without any indigenous energy supply.
Over-pressured fresh water sands induced drilling problems in the initial well MB-1AST and the deeper primary objectives in Middle to Lower Miocene, also predicted to be carbonates, were not reached. A second well to appraise the Pliocene and explore the deep zones will be drilled in early 1996.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California