SAUDI Aramco’s EXPEC Advanced Research Center (EXPEC ARC) claims to have found a better and cheaper way to control hydraulic fracturing in open-hole horizontal wells to improve reservoir contact and enhance production.
EXPEC ARC and partner Halliburton have developed a new jetting tool that bores a short vertical hole to create a weak point to better control the direction of fractures needed to “stimulate” or improve productivity of the well. Before the technique was developed, fracture patterns were hard to control due to variations in unacceptable stress patterns in reservoir rock.
The new technology, called “oriented fracturing”, is expected to help create multiple fractures in a single horizontal well at much lower cost.
“The implementation of this technology will provide an excellent opportunity to increase the productivity of existing horizontal gas wells,” said Nabeel I. Al-Afaleg, acting manager of EXPEC ARC.
“It will also open new horizons in horizontal well stimulation in general.”
Also in development is a second method involving laser technology.
Modelling is under way to optimise the hydraulic fracturing treatment, and subsequent pilot tests will progressively demonstrate additional aspects of these latest advancements.
Schlumberger had previously suggested oriented fracturing as a way of addressing complex reservoir issues such as multiple fractures, near-wellbore tortuosity, maximum proppant concentration, vertical coverage, natural fractures, tortuosity and erosional effects.
These issues have significant impact on reservoir performance and well deliverability. Net pressure matches and geo-mechanical data indicate that effective oriented fracture stimulation treatments can be implemented where other treatments have failed or unacceptable production changes have occurred.
Understanding of near-wellbore stress distribution is critical to implementation of effective fracturing strategies. Reservoir quality variations and mixed lithologies with plastic behaviour will alter the near-wellbore stress distribution, reducing the compressive stress of the rock.
Based on a detailed geo-mechanical model, Schlumberger says the approach can be selectively applied.
It is said to be useful in intelligent completions where zone determination and the design and placement of perforations and/or fractures are critical for optimum production performance. Another application is optimal placement of perforations for reservoir, productivity and stimulation considerations.