| Popis: |
Controlling severe to total lost circulation in naturally fractured/vugular formations has always been challenging, especially in carbonate formations across the Middle East. In these environments, conventional particulate lost circulation materials (LCMs) may not be effective due to the uncertainty regarding fracture and vug sizes. This paper presents an extension to previous work on a high fluid loss squeeze (HFLS) and reticulated foam LCM, providing further technical justification for implementing this technology to cure severe to total lost circulation events. An earlier paper presented laboratory evaluation methodology, test results, and field application of the subject HFLS and reticulated foam LCM. At the time, laboratory test data was presented for an LCM combination that could seal a laboratory simulated fracture size of 9,800 microns. In the current work, a similar laboratory test set up was used to evaluate the efficiency of this LCM combination to seal larger size openings. An adapter with an opening size of 40,000 microns (1.57 inch/4 cm), was used and the combination of HFLS and reticulated foam LCM successfully sealed the opening when tested using an industry standard test set up. The LCM combination was also weighted with barite to determine if the sealing performance was consistent for anticipated applications. The LCM plug formed in the test set up was evaluated for the maximum differential pressure it could withstand in wet conditions, as well as its compressive strength. Under wet conditions, the plug withheld 4,000 psi differential pressure and yielded a compressive strength in the range of 3,170 psi to 4335 psi in duplicate tests. The plugs were also analyzed using CT scanners to visualize the alignment of foam and the particles within the plug. The additional test data supports a more detailed assessment of the LCM combination for specific applications prior to deployment. The results of this extensive laboratory testing on a combination of HFLS, and reticulated foam LCM demonstrates the potential of such materials for reducing or curing severe to total lost circulation events in naturally fractured/vugular formations. The test data presented in this work is the first to be reported in the petroleum industry literature for any comparable LCM at 40,000 microns fracture/slot size. The most notable advantages of improved LCM technology are the increased control of hydrostatic pressure in the well bore by minimizing fluid losses downhole as well as a reduction in well construction costs through decreased rig time associated with lost circulation. |
