**2. Oil and gas platform subsidence**

People commonly use fuel for transportation, electricity, machine, housing, etc. The fuels are produced from oil and gas exploitation. First, we need to explore the existence of oil and gas through exploration using geoscience technique (e.g., geology and geophysics surveys). There are numerous oil and gas reservoirs onshore and offshore all around the world. Platforms are built around offshore reservoirs (**Figure 1**) and also onshore. Once we successfully locate the reservoirs, we do drilling and extract the oil and gas. As the extraction or exploitation continues, the reservoirs may deplete through time due to loss of pore pressure, etc. As consequences, the platform may experience subsidence.

the magnitude of subsidence is already quite large. It may be around 1–3 m. It is true that platform subsidence may reach 1–20 cm per year, especially on old oil and gas platform. The subsidence may continue through years. As mentioned before, continuing subsidence may deform the platform infrastructures, adding the risk for any failure on the platform objects. There are regulations for monitoring oil and gas platform both for onshore and offshore but

The Use of GNSS GPS Technology for Offshore Oil and Gas Platform Subsidence Monitoring

http://dx.doi.org/10.5772/intechopen.73565

89

Strategic position around plate boundary has made Indonesia rich of oil and gas resources, probably one of the largest in the world. Three major plates (e.g., Australia, Pacific, and Sunda Block) meet each other in Indonesia and formed many faults and basins area where usually we can found oil and gas resources. Millions of years of burned planktons getting heated by the mantle have turned them into an oil and also gas. Basin in eastern of Sumatera Island, eastern of Kalimantan, and northern of Java Island is rich in oil and gas resources both onshore and offshore. Bird head of Papua also potentially reserves huge amount of oil and gas. According to data released by Indonesia Ministry of Energy and Mineral Resources, the proven oil reservoirs in Indonesia are

about 3306.97 MMS TB. Meanwhile the potential reservoirs are about 3994.20 MMS TB.

In spite of these potential resources, the areas of oil and gas in Indonesia especially the offshore area are prone to the risk of subsidence failure on the platform facilities. Along with this risk, the tilting and vibrations on the platform are also the risk. Huge oil and gas company is already realized about this situation, as well as the authorities. There are several regular programs on monitoring subsidence, tilting, and vibration on the platform. Nevertheless continues monitoring seems still beyond the agenda since it is relatively too expensive or people

The GNSS GPS principle of measurement is by observing of minimum four satellites and measuring their distance. With the known of their satellite coordinates from broadcast or precise

especially offshore where the risk is higher.

**Figure 2.** Subsidence evidence on oil and gas platform offshore.

do not realize how important it is.

**3. GNSS GPS for monitoring subsidence**

Some platforms have trend of few centimeters per year while others in the order of 10 cm or event more; it depends on how much oil and gas are being exploited, pore pressure decreases, load from rock is there in the surrounding, is level of fluid injection, etc. This subsidence information as mentioned above is mandatory for risk assessment and safety requirement since disaster may occur from that situation.

**Figure 2** shows the physical evidence of offshore oil and gas platform subsidence. From the first picture, we can see jacket walkway was missing, while from the second picture, we can see the landing boat is disappearing into the sea. The different elevation levels between decks are about 5–6 m. In this case by seeing the condition of jacket walkway and the landing boat,

**Figure 1.** Oil and gas platform offshore.

The Use of GNSS GPS Technology for Offshore Oil and Gas Platform Subsidence Monitoring http://dx.doi.org/10.5772/intechopen.73565 89

**Figure 2.** Subsidence evidence on oil and gas platform offshore.

precision in the order of millimeter. The GNSS (GPS) indeed become a revolution in position-

Repeated or continuous monitoring of accurate positions on the objects (e.g., offshore oil and gas platform) may reveal the changing of positions which are representing deformation (e.g., subsidence). Due to oil and gas exploitation, offshore oil and gas platform may experience subsidence. The rates can vary from 1 to 10 cm per year and even more for certain places. This subsidence information is mandatory for risk assessment and safety requirement. Continuing subsidence may deform the platform infrastructures, adding the risk for

People commonly use fuel for transportation, electricity, machine, housing, etc. The fuels are produced from oil and gas exploitation. First, we need to explore the existence of oil and gas through exploration using geoscience technique (e.g., geology and geophysics surveys). There are numerous oil and gas reservoirs onshore and offshore all around the world. Platforms are built around offshore reservoirs (**Figure 1**) and also onshore. Once we successfully locate the reservoirs, we do drilling and extract the oil and gas. As the extraction or exploitation continues, the reservoirs may deplete through time due to loss of pore pressure, etc. As con-

Some platforms have trend of few centimeters per year while others in the order of 10 cm or event more; it depends on how much oil and gas are being exploited, pore pressure decreases, load from rock is there in the surrounding, is level of fluid injection, etc. This subsidence information as mentioned above is mandatory for risk assessment and safety requirement since

**Figure 2** shows the physical evidence of offshore oil and gas platform subsidence. From the first picture, we can see jacket walkway was missing, while from the second picture, we can see the landing boat is disappearing into the sea. The different elevation levels between decks are about 5–6 m. In this case by seeing the condition of jacket walkway and the landing boat,

ing on the twentieth century.

88 Multi-purposeful Application of Geospatial Data

any failure on the platform objects.

**2. Oil and gas platform subsidence**

sequences, the platform may experience subsidence.

disaster may occur from that situation.

**Figure 1.** Oil and gas platform offshore.

the magnitude of subsidence is already quite large. It may be around 1–3 m. It is true that platform subsidence may reach 1–20 cm per year, especially on old oil and gas platform. The subsidence may continue through years. As mentioned before, continuing subsidence may deform the platform infrastructures, adding the risk for any failure on the platform objects. There are regulations for monitoring oil and gas platform both for onshore and offshore but especially offshore where the risk is higher.

Strategic position around plate boundary has made Indonesia rich of oil and gas resources, probably one of the largest in the world. Three major plates (e.g., Australia, Pacific, and Sunda Block) meet each other in Indonesia and formed many faults and basins area where usually we can found oil and gas resources. Millions of years of burned planktons getting heated by the mantle have turned them into an oil and also gas. Basin in eastern of Sumatera Island, eastern of Kalimantan, and northern of Java Island is rich in oil and gas resources both onshore and offshore. Bird head of Papua also potentially reserves huge amount of oil and gas. According to data released by Indonesia Ministry of Energy and Mineral Resources, the proven oil reservoirs in Indonesia are about 3306.97 MMS TB. Meanwhile the potential reservoirs are about 3994.20 MMS TB.

In spite of these potential resources, the areas of oil and gas in Indonesia especially the offshore area are prone to the risk of subsidence failure on the platform facilities. Along with this risk, the tilting and vibrations on the platform are also the risk. Huge oil and gas company is already realized about this situation, as well as the authorities. There are several regular programs on monitoring subsidence, tilting, and vibration on the platform. Nevertheless continues monitoring seems still beyond the agenda since it is relatively too expensive or people do not realize how important it is.
