Unconventional techniques in conventional plays – outside North America

As many as 4,000 fields may have potential for use of unconventional techniques outside North America

Outside North America we have yet to see an example of a large-scale field redevelopment project using only horizontal wells. Nevertheless, we do see potential and have studied three examples:

• In France, where hydraulic fracturing is banned, an abandoned field was revitalized with horizontal wells.
• In China, a field is using a complex development plan involving vertical wells in one zone, horizontal wells in another and water flooding in both.
• In Tunisia, hydraulically fractured horizontal wells produced more water than vertical wells, adding uneconomic operating costs to handle the water.

Saint Martin de Bossenay, France
Discovered by Shell in 1959, the Saint Martin de Bossenay field in the Paris Basin of France was originally developed with vertical wells. By 1996, water represented more than 98% of the produced fluid, and the field was abandoned. Gaz de France and Geopetrol studied the possibility of transforming the field into gas storage.

With rising oil prices Societe Petroliere de Production & Exploitation (SPPE) decided to acquire the concession to redevelop the field with modern technology, specifically targeting non-produced portions of the field as defined by current seismic. The recovery factor improved from 40% to 44% adding 1 million barrels (MMbbl) to the 2P (proven plus probable) reserves. Production of around 400bopd was achieved in 2009.

Tahe Complex, China
Discovered in 1990, the original well found noncommercial volumes of oil. A subsequent well in 1996 found commercial volumes of heavy (17°API) oil and production began the following year. The Tahe Complex consists of a series of interconnected low-amplitude structures, which together make this the largest field in the Tarim Basin. A Phase II development began in early 2003 and was onstream by the end of the year, adding 22,000 barrels per day via 59 additional wells and expanded infrastructure.

In 2006, the first horizontal wells were drilled targeting the Triassic reservoir in which a much lighter, 46°API, oil was trapped. Estimated recoverable reserves jumped from 550 MMbbl in 2006 to 2.4 billion barrels in 2010.

Not all low-productivity fields benefit
Although results were positive using horizontal wells in France and China, we are reminded that not all trials are economically successful. Our third example of the Bir Ben Tartar field in Tunisia found that the use of horizontal wells with fracture stimulation resulted in higher oil production rates, but also significantly higher water cuts. It is speculated that in the case of this reservoir, the horizontal wells were more likely to encounter the natural fractures present, which then brought water up from the lower water-bearing zone. Drilling has returned to vertical wells.

Low-productivity conventional fields hold billions of additional barrels
The number of low-productivity conventional fields outside of North America which may benefit from horizontal wells is estimated at around 4,000. Around 80 percent are located onshore, with the remaining 20 percent in shallow water.

Four countries - Iran, Russia, Mexico, and China - hold more than 50 percent of the potential incremental recoverable barrels. Of the top fifteen countries, many are access limited for international oil companies. Mexico and Argentina, which are attracting interest from IOCs for unconventional plays, may also prove attractive in the low-productivity, conventional plays using similar techniques.

Using a high level assumption that the use of horizontal wells in low-productivity reservoirs could result in a ten percentage point improvement in the oil recovery factor, IHS Energy calculates an additional 136 billion barrels of oil may be recoverable.

Learn more about IHS Energy Strategic Horizons.

Leta Smith, Director, IHS Energy Insight
Posted 16 January 2015

This article was published by S&P Global Commodity Insights and not by S&P Global Ratings, which is a separately managed division of S&P Global.