Increasing the Reach and Selectivity of Completions in Extended Reach Horizontal Wells

Abstract

Over 15 years of production and injection history within the Al Shaheen Field has provided more details on the reservoir heterogeneities and performance of extended reach horizontal wells. This additional data, along with the lateral extent of the reservoirs, has increased the need for longer and more selective horizontal completions. Three primary reservoirs have been developed to date and have different requirements regarding liners and completions. The commonality of all reservoirs is the requirement for long liners and completions in vertically shallow horizontal wells. As the completion philosophy has changed, new approaches have been developed for both deployment and selective isolation. A number of case histories are discussed to illustrate the evolution of the completion requirements. Modifications to zonal isolation, mud over air floatation, and remote triggered packers are some of the cases discussed. Two of the three reservoirs require acid stimulation to improve the production and injection performance of producers and injectors. Effective stimulation can not be accomplished through what would be considered typical placement techniques, due to the extreme lateral departure of these wells in shallow vertical reservoirs. Two techniques used are described along with some issues regarding hole-geometry in acid stimulated wellbores. The paper concludes with some future requirements for the further development of the Al Shaheen Field. Increased selectivity and the need for active zonal control will push the completion requirements beyond where they are today. New completion concepts are being actively researched and developed so that the reservoirs can be optimally managed.

Acid Placement in Acid Jetting Treatments in Long Horizontal Wells

“…If the acid flux becomes too low to efficiently propagate wormholes in the formation, face dissolution of the wellbore, resulting in wellbore enlargement, will occur. Caliper logs run after acid jetting treatments in Qatar (Ritchie et al, 2010) indicate that significant wellbore enlargement did occur as shown in Fig. 4.6.…”

“…For the ultra-long horizontal well, the efficient placement of conventional acids is critical. The difficulty of applying acid (HCl) in long horizontal wells to uniformly remove drilling damage has been identified by several authors (Brink et al 2010;Hoch et al 2010;Ritchie et al 2010). In the long horizontal well completion type, due to the limitation of Coiled Tubing (CT), acid diversion, or foam technology application, Controlled Acid Jetting (CAJ) and Acid Jetting methods are considered as the effective solution to stimulate the well.…”

“…Several papers have been published showing that well completions and intervention methods including future well stimulation techniques are an important component in field development concept (Brink et al 2010;Hoch et al 2010;Ritchie et al 2010).…”