SOCO encounters treating pressure limitations while fracturing

In a field located 23 km [14.3 mi] offshore northwest Congo, SOCO International drilled a well to a total depth 2,665 m [8,743 ft]. The downhole slim-diameter tubing string’s smaller ID limited the maximum allowable fracture treating pressure to 6,000 psi [41.4 MPa]. To overcome this challenge, a delayed fracturing fluid system with low friction pressure was required. In addition, SOCO International sought to simplify operational logistics by using a fracturing fluid compatible with seawater.

UltraMARINE fluid enables effective fracturing at low pressures and provides optimized viscosity

Schlumberger recommended using UltraMARINE fluid, which employs a unique crosslinker designed for use with seawater as the base fluid. The fluid features a guar polymer slurry as the base with a dual-crosslinking mechanism. This resulted in low friction pressures and provided optimized viscosity at bottomhole conditions to enable successful proppant placement within the pressure limitation of the string. Due to the complex nature of the downhole test string, the HiWAY technique was also used to design a proppant placement schedule that reduced screenout risk.

Productivity index increased 14-fold

UltraMARINE fluid made it possible to effectively fracture stimulate the prospective interval and inhibit any potential seawater scale precipitation while keeping treating pressure below limitation. The HiWAY flow-channel fracturing technique maximized fracture conductivity with no screenout. The integrated use of the UltraMARINE fluid and the HiWAY technique resulted in a 14-fold increase in the postfracturing producitivity index in comparison with prefracturing production.