Remember me | Forgot password
For full content view: Log in Now!
As producing zones mature, drilling can become increasingly difficult as the difference between pore pressure and fracture pressure decreases. Mud densities required to maintain shale stability can be very close to the pressure required to fracture depleted reservoirs. Such situations require special drilling fluids with low equivalent circulating densities (ECD), since the effective density increase due to the additional circulating pressure can, in conventional fluids, be higher than the margin between pore and fracture pressures. Furthermore, drilling in mature fields is often severely cost-constrained, causing some operators to try small holes and techniques such as coiled tubing drilling (CTD) and through-tubing rotary drilling (TTRD). All of these techniques increase the importance of drilling fluid design, as the small borehole sizes employed are likely to further increase ECD-related problems. Thinner fluids are more prone to material sag, and sag itself can be more critical in small hole sizes due to very narrow annular clearances.
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.
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:
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 CustomerService@worldoil.com.
World Oil's specialized upstream Engineering Data Tables featuring the Drill Bit Classifier, Tubing Tables and more. Get Total Access today.
Denver, CO - December 11-13
Doha - January 20-22
Cancun - January 27-29
All material subject to strictly enforced copyright laws.
© 2013 World Oil. © 2013 Gulf Publishing Company.