Lately, there has been much discussion regarding the Masela Oil and Gas Working Area Block (WK) development scheme, located in the sea off Maluku. There is debate over which scheme is better between onshore and offshore. This article will discuss in general the comparison between the two schemes.

What is the meaning of onshore and offshore?

Onshore, translated from English, which means land that approaches the sea or is on land and not at sea1, refers to work related to buildings/structures located on land to the coastline for oil and gas exploration and exploitation activities. Examples of onshore works are onshore refineries and boreholes.

Figure 1 Example of an onshore project


Figure 2 Drilling rig onshore


Meanwhile, offshore, which means far from or far from the mainland, is an exploration and exploitation of oil and gas carried out offshore or far from the mainland. In offshore activities, exploration and exploitation are carried out using fixed offshore platforms (jacket, jack-up) or floating (Spar, TLP, FPSO, and others).

Figure 3 Jacket type offshore platform

Source: dan

Figure 4 Offshore FPSO type platform

Source: and

What is the difference between Onshore and Offshore?

Onshore refineries are more accessible to reach than offshore refineries because the location of the refineries themselves can be in the middle of a forest, a mountain peak, in the middle of a desert, even on the edge of a city or village.2 The provisions needed to drill onshore wells are somewhat more accessible than offshore. However, because there has been a lot of exploration and exploitation on land, the chances of finding new oil and gas reserves are smaller than in the oceans.

Besides, the challenges for oil and gas exploration offshore are more significant than onshore. Onshore refinery construction projects must consider the strength of the ground for the foundation and wind loads, while at sea, other aspects need to be taken into account, namely the load arising from the movement of currents and ocean waves. It requires more complex human resources and expertise in designing the refinery.

Moreover, the operational costs required for offshore exploration are more expensive than onshore. From a development perspective, the structural materials used in offshore projects cannot be arbitrary. There need to be considerations related to marine environmental factors such as corrosion and failure caused by marine biota growth. However, the advantage of an offshore rig is that the structure can be moved because it uses floating platforms such as Floating Production Storage and Offloading (FPSO) and Tension Leg Platform (TLP) so that it can be reused for exploration in other locations after it has finished extracting oil and gas from the previous location.

The following is an example of a comparison regarding the above matters: the Masela Oil and Gas Working Area Block in Maluku


Figure 4 Offshore FPSO type platform


It should be noted that the Oil and Gas Working Area Block is located in the sea off Maluku. In the onshore scheme, oil and gas exploitation is carried out at sea using floating offshore platforms for the drilling process. The drilling results are then sent to the mainland using submarine pipes or tanker ships to be further processed into liquefied natural gas (LNG) so that the natural gas from the drilling can be sold and consumed. Apart from the need for offshore drilling facilities, in this scheme, because the wells are located in the high seas, LNG production facilities on land are also needed, and a piping system or sea-to-land transportation. Unlike the offshore scheme, which does not require production facilities on land, LNG production activities can be carried out on platforms or platforms. In the offshore scheme, natural gas from drilling is directly processed into LNG, sent ashore by tanker to be directly sold and consumed. However, the offshore scheme’s use requires a more complex offshore platform because LNG production must be carried out on a platform.

The following are some of the differences in the onshore and offshore schemes3:

InfrastructureOffshore platforms (drilling), onshore production facilities, transportation systems (pipelines or tankers)Offshore platforms (drilling and production), transportation systems (tankers)
The land acquisitionUnlimitedLimited
The Land ConflictPossible, because the construction of facilities on land is necessaryLow Possibility, due to activities on the high seas
Social and Environmental EffectPossible, due to land activity,, the environment can be pollutedLess social impacts, the environment may be polluted
Facilities after the exploitation period is overFacilities on land are difficult to move, and can be used for LNG production from other wellsThe offshore platform can be moved to another exploitation location because it is floating
MaintenanceIt is easier and cheaper because of access on landIt is more difficult and expensive because it located at the high sea

Distribution of oil and gas blocks that are managed offshore and onshore

In Indonesia, there have been many oil and gas exploitation activities in onshore and offshore schemes. The following is some data on the distribution of oil and gas blocks in Indonesia4 (SKK Migas report on January 1, 2020).


NoWorking AreaBlock/LocationOperatorCommodityStatus
1Region I (Sumatra, Riau Islands, dan Natuna Island)BangkoPetrochinaOil and GasOnshore
3BelidaSele RayaOil and GasOnshore
5Aceh Blok AMedcoGasOnshore
6CPPBOB – BSP dan PertaminaOilOnshore
7CorridorCONOCO PHILLIPSGasOnshore
8DuyungWest NatunaOil and GasOffshore
9GebangEMPOil and GasOnshore and Offshore
10JabungPetrochinaOil and GasOnshore
11Jambi-MerangPHEOil and GasOnshore
12KakapStar EnergyOil and GasOffshore
14Karang AgungODIRAOil and GasOnshore
15KisaranPacificOil and GasOnshore
16Korinci BaruKalilaGasOnshore
17Krueng ManeENIOil and GasOffshore
19LemangMandala EnergyOil and GasOnshore
20LematangMedcoOil and GasOnshore
21LhokseumaweZaratexGasOnshore and Offshore
23Selat MalakaEMPOil and GasOnshore and Offshore
24Merangin IISele RayaOil and GasOnshore
25Laut Natuna Blok APremierGasOffshore
26Sumatra Utara Blok BPHEOil and GasOnshore
27Sumatra Utara OffshorePHEOil and GasOffshore
28North West NatunaAWEGasOffshore
29Ogan KomeringPHEOil and GasOnshore
30PalmerahTatelyOil and GasOnshore
31PandanTropikOil and GasOnshore
32Raja and PendopoPHEOil and GasOnshore
33RimauMedcoOil and GasOnshore
34RokanChevronOil and GasOnshore
35Selat PanjangSGEOil and GasOnshore
36SembilangMandiri Panca UsahaOil and GasOnshore
38South JambiJindiOil and GasOnshore
39South Natuna SeaMedcoOil and GasOffshore
40South SumatraMedcoOil and GasOnshore
41Bukit Barisan SouthwestRizkiGasOnshore
42TongaEMPOil and GasOnshore
44Air Komering BaratTiarabumiOil and GasOnshore
45Region II (Jawa dan Kalimantan)Alas Dara KemuningPertaminaOil and GasOnshore
46BangkanaiMedcoOil and GasOnshore
47BaweanCamarOilOnshore dan Offshore
48Bengara IMedcoOil and GasOnshore and Offshore
50BuluKris EnergyGasOffshore
51CepuExxon MobilOilOnshore
52KangeanKangean EnergyGasOnshore and Offshore
54Madura OffshoreOphirGasOffshore
55Selat MaduraHusky-CNOOCOil and GasOffshore
58ONWJPHEOil and GasOffshore
60PasirPasirOil and GasOnshore
61RanduguntingPHEGasOnshore and Offshore
62Sanga-SangaPHEOil and GasOnshore
63SimenggarisJOB MedcoOil and GasOnshore
64Southeast SumatraPHEOil and GasOffshore
65TarakanMedcoOil and GasOnshore
66TubanPHEOil and GasOffshore
67WailawiBenuo TakaOil and GasOnshore
68WainPandawaOil and GasOnshore
69West Madura OffshorePHEOil and GasOffshore
70Region III (East Indonesia)BerauBPOil and GasOffshore
73East Kalimantan and AttakaPHKTOil and GasOnshore and Offshore
74East SepingganENIGasOffshore
75GanalChevronOil and GasOffshore
76KasuriGentingOil and GasOnshore dan Offshore
77Kepala BurungPetrogasOil and GasOnshore
78MahakamPHMOil and GasOnshore dan Offshore
79Selat MakassarChevronOil and GasOffshore
81Muara BakauENIGasOffshore
82MuturiBPGasOnshore dan Offshore
83RapakChevronOil and GasOffshore
84SalawatiPetrogasOil and GasOnshore and Offshore
85SebukuPearlGasOnshore and Offshore
86SengkangEnergy EquityGasOnshore
87Senoro-ToiliJOB MedcoGasOnshore and Offshore
88Seram Non BulaCITICMinyakOffshore
89Tarakan OffshoreManhattanOil and GasOffshore
90West SalawatiMontD’OrOil and GasOnshore and Offshore

By Hadian Bagas Widyawan and Kevin Alief Adityaputra

  1. Walter, E., 2008. Cambridge advanced learner’s dictionary. Cambridge university press.
  2. Walter, E., 2008. Cambridge advanced learner’s dictionary. Cambridge university press.
  3. Annisa Ayu Artanti, 2016. Kelebihan dan Kekurangan Fasilitas Offshore atau Onshore Blok Masela. (diakses 02/02/2021)Annisa Ayu Artanti, 2016. Kelebihan dan Kekurangan Fasilitas Offshore atau Onshore Blok Masela. (diakses 02/02/2021)
  4. Badaruddin, M., 2018. Dinamika Industri Migas dan Pertambangan di Indonesia. Jakarta: Jurusan Ilmu Poilitik, Universitas Bakrie