Case Study: Application of 8-1/2" SD6545 PDC Bit in Well Su 76-14-20X, Sulige Gas Field
Project Background
Sulige Gas Field’s Taiyuan Formation has long been a tough nut to crack for onshore drilling teams in China. Made up of interbedded gray medium-fine sandstone, dark gray mudstone, and thin coal seams, this interval features high abrasiveness and moderate drillability, making consistent, efficient drilling a major challenge.
Historically, conventional PDC bits used in the Su 76 block only delivered around 500 meters of single-bit footage, with average ROP (Rate of Penetration) failing to hit 10m/h. This not only dragged out drilling cycles but also led to frequent tripping operations and ballooning operational costs. When drilling Well Su 76-14-20X, the 40607 Drilling Team turned to Shaanxi Hainaisen Petroleum Technology for a fit-for-purpose bit solution, aiming to boost efficiency in the Taiyuan Formation, cut down tripping times, and lower overall project costs.
Bit Selection
To tackle the unique lithological challenges of the Taiyuan Formation, our engineering team recommended the 8-1/2" SD6545 PDC Bit (Bit Serial No.: A2242), a product independently developed by Shaanxi Hainaisen Petroleum Technology. This bit is purpose-built for medium-hard interbedded sandstone and mudstone, with key design upgrades tailored for tough drilling conditions:
- A 5-blade impact-resistant base body fitted with 19mm high-wear PDC cutters, delivering top-tier impact and abrasion resistance to withstand the formation’s high abrasiveness;
- Redesigned hydraulic flow channels on the blades to improve cuttings removal and bit cooling, drastically reducing the risk of bit balling in interbedded mudstone intervals;
- A reinforced gauge protection structure to keep the wellbore in gauge and minimize sticking risks during tripping.
Field Performance & Verified Core Data
The bit was run in hole at 2800m and pulled out at 3546m, covering the entire target Taiyuan Formation interval without issue. All on-site operational data was verified by the 40607 Drilling Team, as shown below:
| Parameter | Actual On-Site Value |
|---|---|
| Bit Model | 8-1/2" SD6545 PDC Bit |
| Bit Serial Number | A2242 |
| Run-in Depth | 2800m |
| Pull-out Depth | 3546m |
| Total Single-Bit Footage | 746m |
| Net Drilling Time | 40 hours |
| Average ROP (Rate of Penetration) | 18.65m/h |
| Drilled Formation | Taiyuan Formation (2800m – 3546m) |
| Drilling Team | 40607 Drilling Team |
Throughout the entire drilling process, the bit performed stably, with no bit bounce or erratic torque. WOB (Weight on Bit) and rotary speed stayed consistent, and cuttings returned to surface smoothly. After pulling the bit out of the hole, inspection showed uniform wear on all PDC cutters, no chipped or lost teeth, and fully intact gauge protection—meaning the bit was still in good condition for further use if needed.
Performance Comparison with Offset Well
We compared this result with offset well Su 76-14-19X, which used a conventional PDC bit for the same 2800m–3550m interval in the same block. The offset well’s core metrics were: 520m of single-bit footage, 58 hours of net drilling time, and an average ROP of 8.97m/h.
Against this baseline, the SD6545 bit delivered game-changing improvements:
- 43.5% higher single-run footage: Jumping from 520m to 746m, the bit finished the entire Taiyuan Formation in one run, cutting out one full tripping operation;
- 107.9% faster average ROP: From 8.97m/h to 18.65m/h, slashing net drilling time by 18 hours and drastically shortening the overall drilling cycle;
- Major cost savings: Based on the block’s standard daily drilling rate, the 18-hour time cut directly saved over RMB 20,000 in operational costs, not to mention the savings on bit purchases and tripping labor.
Conclusion
The successful application of the 8-1/2" SD6545 PDC Bit in Well Su 76-14-20X has fully solved the long-standing problems of slow ROP and limited footage in the Taiyuan Formation of the Su 76 Block, Sulige Gas Field. With 746m of single-run footage and an 18.65m/h average ROP, this bit has delivered real, measurable efficiency gains and cost reductions for the drilling team.
At Shaanxi Hainaisen Petroleum Technology Co., Ltd. (Website: https://www.hnsdrillbit.com/), we continue to refine our bit designs for different blocks and formation types, providing high-quality bit products and end-to-end technical services to support efficient oil and gas development both in China and globally.
