A field was discovered in 1972 with current ten drilled wells with different reservoir characteristics throughout the structure. The A reservoir is an irregular carbonate buildup of Peutu limestone oriented north-northwest. The thickness of this unit varies from 45 meters (147.6 ft) in A-8 to 458 meters (1,502.2 ft) and in A-7A with a gas column of 120 meters (393.6 ft). The A field is 2 to 3 kilometers wide by 9 kilometers long and covers area about 20 square kilometers. The
reservoir in A Field is Peutu limestone beside the Tampur Dolomite below. Thin section analysis and investigation of drill cuttings indicate that Peutu
formation contains 37 carbonate lithofacies. For modeling purposes, these facies are grouped into 5 reservoir facies (rock types) based on combination of
depositional facies and diagenetic unit. The tampur is modeled as dolostone facies with some dispersed shale streaks. Combination of Seismic interpretation and general tectonic history indicate that the reservoir was higly faulted across the structure where the trend were in NESW direction. Well tests indicate good productivity for wells located near major faults and analysis of pressure data indicate permeability values about 1.5 - 3 md higher than matrix rock permeability from core analysis. This is an indication of natural fractures near fault planes that directly control the productivity. Current development strategy was taking the advantage of natural fracture existence by placing the well near the fault. However, some detailed works are required to support the decision as it will involve a high amount of investment due to sour gas quality.
Detailed evaluation of natural fracture existence is proposed as a combination of well test result interpretation, fracture indication by log, core and Flow Zone Index assessment. The result was indicating that most of productive areas are located near the fault that expected to contribute significantly to the production by fracture existence. Therefore, the development plan for such area should be taken into account especially for first phase of development.