Schlumberger

Performance Report: Brazil: One MD-3 Shaker Outshines 3 in Successful South America Debut

Challenge: The MD-3 Shaker underwent a field trial on a major operator land drilling site. The main trial objectives were to test the flowrate handling capacity and make a qualitative assessment of the solids handling and conveyance capacity of the MD-3 Shaker. Shaker screen life was also measured and compared to historical benchmarks. The operator development well was drilled in a J-shape standard slim well, including a cemented 3½-in. completion using the measured drilling parameters in Figure 1.

Solution: The MD-3 Shale Shaker is a multi-deck shaker engineered to provide efficient solid separation. The shaker was set in a parallel configuration, meaning the bottom decks were running in parallel with each other and using the same mesh (for the majority of the test). For this trial, the MD-3 unit was installed between the shaker cutting tank and the first fluid storage silo. Tests were conducted on 12¼-, 8½- and 6-in. sections.

Result: 12¼-in. section: The MD-3 unit was rigged up to take 100% of the flow from the bell nipple, with the three rig-owned units on standby, but isolated. The mud system was KPM, a KCl polymer system. 28 gumbo screens with 0.8 x 118 mm openings were used on the scalping deck and the middle and bottom decks were dressed with 84 XR screens. HC screens were later used in the section due to their superior performance in sticky clays. For the first 40 m (131 ft) drilled, the MD-3 unit was able to handle the complete flow rate of 2,500 L/min. At 40 m (131 ft), the screens partially blinded in unconsolidated sands and the total flow rate was reduced to 1,250 to 1,500 L/min. The Md-3 unit was able to handle 750- 900 L/min of the total flow (60%). This result was historically better than previous wells, where flow was usually limited to <1,000 L/min in total due to excessive blinding across the three rig shakers. Once into the Breda, Rupel and Asse clay formations the flow rate was increased to 3,000 to 3,100 L.min in total, with the MD-3 unit treating 2,000 to 2,700 L/min (66 to 88% of total flow). Once into the lower Tertiary clays and Upper Cretaceous chalk, the MD 3 unit was able to treat up to 3,400 L/min (100% total flow) with 84/105 (need to specify HC or XR) mesh on the primary decks. 8½-in. section: After a successful cementation of the 9⅝-in. casing and the installation of the BOP the section was started with the MD-3 unit rigged up. The scalping deck was dressed with 38 XL screens, while the middle and bottom decks were dressed with 165 XR and 165 HC screens, respectively. The shoe track was drilled out with the previous KPM water-based mud and then during the drilling out of the cement the well was displaced to 1.25 SG VCM. Once the mud was displaced, drilling of the fresh formation started. The mud system was VCM, a VERSACLEAN LTOBM system. From the beginning of the 8½-in. section the MD-3 unit was able to process the total flow rate from the well. The flow ranged from 1,600 L/min during rotary drilling mode, up to 2,200 L/min while drilling in sliding/steering mode. The MD-3 unit was positioned at the side of the 40 m3 rectangular cutting tank and with 100% of the flow and a dry discharge, the cuttings were stacked in a small area and potentially overflowing the cutting tank. Most of the time the cuttings were manipulated to the sides to keep the shaker running, but at night the third-party cuttings-moving equipment was not available so flow was occasionally switched to the rig shakers to spread the cuttings across the length of the tank. 6-in. section: The 7-in. liner was successfully cemented and BOP pressure-tested. The section was started with the MD-3 unit rigged up. During the drilling out of the cement the mud was weighted up to 1.55 SG. Once the mud system weight reached 1.55 SG an FIT was performed and drilling continued. The section was terminated early due to well-control problems requiring increasing mud weights, and finally requiring a liner to seal off a high-pressure zone. The mud system was VCM., a VERSACLEAN LTOBM system.

Upon installation parallel to the three cascading shakers, the MD-3 was used in the 12 ¼ in. hole, which was being drilled with a 9-9.2 lb/gal paraffin-based Paradril drilling fluid system with a viscosity range of 55-70. The same drilling fluid was used in the subsequent 8 ½ in. interval.

To begin the test in the top hole, the MD-3 shale shaker was dressed on the top deck with an API 35 (30 MG) screen and both primary decks were dressed with an API 100 (165 XR) screens. This set-up was used to test the flow rate handling capacity of the MD-3 shale shaker with the following results:

  • During drilling of the upper 12 ¼ in. section, the MD-3 processed an average of 750 gpm of the total 850 gpm circulating volume (88%). The average ROP was 262 ft/hr (80 m/hr) with an instantaneous ROP of 328 ft/hr (100 m/hr).
  • When utilizing API 120 screen in the lower portion of the 12 ¼ in. hole, the MD-3 was able to process 700 - 800 gpm; the shaker processed 750 gpm with a 98 - 131 ft/hr (30-40 m/hr) ROP when API 140 screens were used.
  • To compare the screen life, at the conclusion of the 12 ¼ in. section a true scrap rate was determined for each screen type. A scrap rate of 22% for the MD-3 screens compared to a scrap rate of 87% for those of the three rig cascade shakers. A very conservative estimate of 75% of the total circulating flow was received and processed by the MD-3.
  • During drilling the 8 ½ in. section, the MD-3 processed an average of 425 gpm of the 575 gpm circulating volume (74%) at an average ROP of 10 ft/hr (3 m/hr) with an instantaneous ROP of 16 ft hr (5m/hr). In the later part of the 8 ½ in. section the MD-3 shaker was screened up to test the capacity with finer mesh screens on the two lower primary decks. API 140 (230 XR) screens and API 170 (270 HC) mesh screens were installed and tested during the 8 ½ in. interval. The three competing shakers used API 170 (200 mesh) screens.
  • The ability to process the full planned flow rate with the MD-3 installed was extremely beneficial compared to the typical flow rate restrictions that were present previously with the four rig cascade shakers.

The overall performance of the MD-3 during the comparative field trial was nothing short of remarkable, effectively validating its operational and economic advantages. During the trial, a single MD-3 effectively processed nearly 300 more bbl of cuttings than three cascade shakers combined with the utmost in reliability and screen life.


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