Saudi Aramco has been conducting a successful fracturing for sand control strategy in high pressure/temperature high gas rate screenless completions in the Jauf sandstone, which exhibits high sanding tendency in certain zones throughout the reservoir. The strategy combines a number of techniques, including indirect fracturing from oriented perforated thin consolidated zones, tip screenout design, use of a combination of resin coated proppant (RCP) with fibers, forced closure, and a carefully controlled flowback procedure.
Although solids-free high rate gas production has been achieved in the majority of wells for which the strategy has been implemented, a reduction in fracture conductivity in the form of positive skin has been detected in several hydraulically fractured wells in which pressure buildup tests have been conducted. Part of this negative effect results in all likelihood from partial perforation effects, given that the interval from which a fracture is initiated is usually perforated in high Young's Modulus rock and limited to 30-40 feet. Thus, the fracture is initiated away from the high sanding tendency zones and extended into such zones. The other main component for the positive skin are the fibers used for proppont flow back control purposes since it is well known through extensive industry testing that the combination of resin coated proppant and fibers can reduce fracture conductivity in treated wells.
Lab testing aimed at identifying potential conductivity reduction mitigation techniques, while maintaining the ability to achieve effective formation sand control, showed that the combination of two new additives, when mixed with proppant, was able to achieve both key requirements. Hence a suitable candidate was selected for a field trial.
This paper discusses the results of the first field trial of the additives tested as an alternative to the resin coated proppant/fibers mixture and the lessons learned from the trial. A direct comparison between the well treated with the new additives and an offset well previously treated with resin coated proppant and fibers, showed that the well treated with the new additives yielded better productivity despite the fact that its kh was only 1/3 of the kh of the offset well. A posttreatment pressure buildup tests was conducted in each of the wells for a valid comparison.