Bangestan, Strategic Oil Reservoir
Iran hopes to exceed 5 mb/d oil production under its 20-Year Vision Plan. To that end, it hopes to invest in enhanced recovery from the fields that have long been operational. Most of Iranian oil fields whose output is over 300,000 b/d are in the second half of their life. That is while less than 30% of their oil reserves has been extracted and they would need modern technologies in order to increase their production. An interesting point to know is that through utilizing these technologies it would be possible to raise the enhanced recovery from oil fields to more than 80%.
One of the fields Iran can count on for enhancing its production in the long-term is the Mansouri oil field and more specifically its Bangestan oil reservoir.
The Bangestan reservoir was offered for foreign investment during a conference held in Tehran a couple of years ago on introducing opportunities for investment in Iran’s oil and gas sector.
Over recent years, the project for production from the Mansouri oil field was studied at the Committee of Consultants in the Directorate of Reservoirs at National Iranian Oil Company (NIOC).
According to the Corporate Planning Directorate of NIOC, the scenarios envisaged for recovery from this field include natural depletion, gas and water injection to study various parameters including output flow and downhole pressure. This field enjoys good potential for prospective production and development. Studying the Bangestan reservoir of the Mansouri field requires more research activities in the future. Such activities have already started. Some of them pertain to artificial lifting, hydraulic fracturing and enhanced recovery methods.
Over recent years, Iran’s petroleum industry, particularly National Iranian South Oil Company (NISOC) has been trying to enhance crude oil production and processing in the Mansouri field from 60,000 b/d to 100,000 b/d. The project has had 97.5% progress.
The only remaining part of the first phase of development of the Mansouri field pertains to the completion of a production and desalination plant with a capacity of 75,000 b/d. Another objective sought in this development project is to increase oil recovery to 150,000 b/d.
The high recovery rate has created a special status for the Mansouri field and added to its significance.
The latest estimates indicate that the average rate of recovery from oil fields in Iran is about 28%. That is while the rate of recovery from the Asmari reservoir of the Mansouri field is 47%, indicating the high potential of this oil field.
The Mansouri field is located 60 kilometers south of Ahvaz, 50 kilometers west of Mahshahr Port and 40 kilometers east of the Ab Teimour field.
Discovered in 1963, the field started production in 1973. Oil flow from the Bangestan reservoir of the Mansouri field is currently under way in the area run by Karoun Oil and Gas Production Company (KOGPC).
KOGPC is the largest subsidiary of NISOC with an output of over 1 mb/d.
The Bangestan reservoir of the Mansouri field has a production unit with a nominal capacity of 75,000 b/d, a desalination unit with a rated capacity of 35,000 b/d and a gas compressor station with the installed capacity of 30 mcf/d.
The reservoir is estimated to hold 15 billion barrels of oil in place. So far, a total of 347 million barrels of oil has been extracted from the Bangestan reservoir and there is potential for enhanced recovery by up to 79,000 b/d.
Official data shows the average recovery rate of oil in Iran is 24% now. This figure is 48-65% in other countries. Of course, Iranian Petroleum Ministry officials say the rate of recovery for Iranian oil fields varies from 7% to 35%.
NISOC-run oil fields are not producing oil at maximum efficient rate (MER) and the reservoirs are likely to suffer damage.
In the 1940s, the average production from Iranian oil fields stood at 18,000 b/d. Today the figure has fallen to 2,000 b/d.
As oil fields get close to the second half of their life, they experience an annual decline of 330,000 to 350,000 b/d of oil in offshore wells. Therefore, in order to realize production objectives in the vision plan, enhanced recovery from old reservoirs like Bangestan should be envisaged.