Press Esc to close



For full content view: Log in Now!

  • Realistic core testing improves sandstone acid treatment

    S. A. Ali, C. DeVine, L. Kalfayan and C. Uchendu

    Core flow testing has long been an accepted method for assessing formation sensitivity to treatment fluids and evaluating sandstone matrix response to acidizing treatments. However, core flow tests are often conducted with standard core material like Berea sandstone, rather than the actual formation core. Furthermore, test procedures typically use undamaged cores.1, 2, 3 Studies with undamaged cores can be meaningful in assessing rock's sensitivity to particular acid formulations, including the severity of acid/ formation reaction-product re-precipitation. However, in evaluating effectiveness of specific hydrofluoric (HF) acid systems for removing permeability damage and limiting formation acid sensitivities, testing undamaged cores is not sufficient. A systematic approach to core flow testing uses procedures that damage cores in a manner representing realistic damage mechanisms, then remove damage with appropriately selected HF treatment systems (and non-acid, pre-acidizing treatment systems, if necessary). The degree of damage removal and stimulation is measured after each treatment step.

This area of the site is restricted. In order to gain access, please either Log In, or subscribe to World Oil.

Two options are available to you for creating an account.

1. Get a Free Trial Subscription to World Oil Magazine and gain immediate access to select content on World Oil Online.

Start a Free Trial Subscription and gain immediate access to the complete current issue of World Oil Magazine. Plus, you’ll receive 3 upcoming issues of World Oil Magazine in print or digital format.* You also receive access to the Energy Events Calendar, Industry Statistics and WO Wire’s news and industry coverage.

Free Trial

2. Purchase a subscription to World Oil magazine and gain immediate and complete access to World Oil Online. As a Total Access subscriber you will have access to all areas of the site available to registered users and free subscribers as well as having access to such premium content areas as:

  • The Archives section containing over ten years of complete magazine archives,
  • The WO DataHub's engineering tables and directories,
  • The World Oil annual forecasts, including past predictions,
  • Select World Oil technical handbooks,
  • And much, much more!


Physical copies of this content may be available for purchase. Visit the Reprints & Back Issues section.

If you are already a paid subscriber and do not have access, please email



Engineering Data Tables

World Oil's specialized upstream Engineering Data Tables featuring the Drill Bit Classifier, Tubing Tables and more. Get Total Access today.


2013 Fracturing Technology

2013 Fracturing Technology


Upcoming Events