Bass Strait drilling and production

Offshore wells rarely go straight down. Most are drilled out at an angle in many directions in order to access different parts of an oil or gas field. Some wells penetrate rock formations several kilometres away from the platforms.

Bass Strait oil wells vary in length from about 2km to 8km and the maximum horizontal distance from a platform is more than 6km. Drilling is conducted using computer controlled, extended reach rotary drills which cut through rock using a drill bit with steel or diamond tipped teeth.

The design of individual wells varies considerably depending on the size and characteristics of the field, the rate of flow and the long-term production strategy.

The Bass Strait oil and gas fields and reservoirs are monitored by ExxonMobil's engineers and geoscientists using sophisticated computer modelling applications. A reservoir can be re-drilled several times as the best well locations change as the field matures and becomes depleted.

When new drilling is required a special drilling rig will be attached to the existing platform where it will usually remain for several months. Most drilling rigs are run by contractors who take their rigs to oil fields all over the world, from Norway, Malaysia and the Middle East, to Bass Strait.

Whilst the basic idea of drilling has not changed much over the years the technology has improved dramatically. In fact, the robotics, space age metals and remote sensing devices used for offshore oil exploration and production rival the space station as advanced technologies for a hostile environment.