TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractWhen designing an acid treatment, the engineer often faces the question of what diversion method will be the most effective yet least damaging to the formation. Previous work has been published about evaluation methods, and conceptually diversion theory seems straightforward, but detailed post-job analysis and treatment optimization is often forgotten, especially when post-job production results meet or exceed expectation. Once a particular diverter is selected, the next question often is how much is required? If too small of volume is used, then treatment diversion will not be achieved. If too large of volume is used, then cleanup times and the risk of permanent damage increases.Viscoelastic surfactants have recently become a popular additive for diversion pills, based on their polymer-free chemistry. Various formulations, including foam, have been successfully applied in acid stimulation treatments, but little post-job analysis has been published. Viscoelastic fluid properties vary over a pH range during acid spending on the formation and when foamed, determination of bottomhole properties is further complicated.A tube viscometer and parallel core flow cells were utilized to determine the rheological properties and diversion effectiveness of various formulations of foamed viscoelastic surfactant at bottomhole conditions. An optimum formulation was determined, and this fluid was then applied and evaluated in a field application. A down-hole memory gauge was run during a coiled tubing acid treatment, and delta pressure changes were evaluated to determine the diversion effect.
TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractTo conventionally drill, complete and produce horizontal and multilateral wells with zero skin is not an easy undertaking. Much attention has been given to "best oil field practices" in both drilling and production processes, but the reality is that formation damage will often have to be addressed sometime during the life time of the well.Formation damage due to drilling and scale formation is common problem in carbonate reservoirs that can be remediated using chemical means. The success of any treatment however, requires a complete understanding of the problem and a solution that will address the majority of the damage. The solution evolves with time and experience. Extended reach intervals with variable permeability complicate the process. Reservoir and fluid characteristics, cleanup fluid chemistry, and operational considerations must always be considered.The acidizing experience and an improved understanding of how to effectively treat long and heterogeneous intervals in carbonate formations is rapidly evolving in Saudi Arabia. Water injectors, oil producers and wastewater disposal wells have been treated and are reviewed in this study. These wells have different configurations including: vertical, horizontal, extended reach, and multilateral with open hole and cased completions. Several acid placement and diversion techniques have been applied and a specialized treatment package was developed based on the latest coiled tubing and chemical diversion technologies. Laboratory studies, lessons learned and specific design guidelines from both successful and less than expected well treatments are highlighted in this work.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.