Case Study: Well Su 75-70-17X - Yanchang Formation Drilling Operation
Project Basic Information
- Operating Block: Sulige Gasfield Block, Ordos Basin
- Well No.: Su 75-70-17X
- Drilling Crew: No. 50056 Drilling Team
- Target Formation: Yanchang Formation (interbedded sandstone and mudstone, locally with gravel, mudstone section prone to balling, medium abrasivity)
- Cooperating Service Provider: Shaanxi Hainaisen Petroleum Technology Co., Ltd.
- Official Website: https://www.hnsdrillbit.com
Bit Selection & Technical Solution
Aiming at the on-site pain points of the Yanchang Formation in the Sulige Block—frequent interbedding of sandstone and mudstone, severe mud balling in mudstone sections, low drilling rate, and insufficient footage—the Hainaisen technical team customized the 8-3/4" SD9633 PDC Bit based on the well's logging data. The core design adaptabilities are as follows:
- Optimized 5-blade structure, balancing rock-breaking efficiency and downhole stability;
- High wear-resistant and impact-resistant PDC cutters, suitable for gravel-bearing sandstone and mudstone formations of the Yanchang Formation;
- Customized hydraulic flow channels to enhance bottomhole cleaning and fundamentally resolve mud balling;
- Optimized cutter arrangement to cover rock-breaking requirements for both soft mudstone and hard sandstone sections.
On-site Application Core Data
| Index | Actual Operating Parameters |
|---|---|
| Bit Model | 8-3/4" SD9633 PDC Bit |
| Bit Serial No. | 2318 |
| Running Interval | 975m ~ 1890m |
| Total Footage | 915m |
| Pure Drilling Time | 27h |
| Average ROP (Rate of Penetration) | 33.9m/h |
| Operating Formation | Yanchang Formation |
| Out-of-hole Bit Condition | Slight blade wear, no tooth breakage, no mud balling, reusable for secondary run |
On-site Application Results
In this operation, the SD9633 PDC Bit completed the entire drilling of the Yanchang Formation from 975m to 1890m in one trip. With a total footage of 915m and pure drilling time of only 27 hours, the average ROP reached 33.9m/h.
Compared with the average ROP of 20-25m/h for conventional bits in the same formation of the block, this operation achieved an ROP increase of over 40%. This directly shortened the drilling cycle, eliminated one trip of tripping, and significantly reduced drilling construction costs and downhole complex risks.
Meanwhile, the bit's excellent hydraulic design completely solved the mud balling problem in the mudstone section of the Yanchang Formation. The entire drilling process was stable with no stick-slip. The out-of-hole bit showed slight blade wear and intact cutters, meeting the requirements of repeated runs for similar formations in the same block and further improving bit utilization efficiency.
Customer Authentic Feedback
Foreman Li of No. 50056 Drilling Team (On-site Verbatim Summary)
"For years, drilling the Yanchang Formation in the Sulige Block has been a headache for us—low drilling rate and mud balling causing stuck pipe. Previously, with 8-3/4" bits from other suppliers, a single trip could only drill over 600 meters with a ROP of only 22-23m/h. Severe mud balling sometimes forced mid-trip tripping, which delayed the construction period and increased costs significantly.
Hainaisen's SD9633 was a pleasant surprise. It drilled 915 meters in one single trip, with an average ROP of 33.9m/h. This cut the pure drilling time nearly in half and reduced one tripping operation, saving over 100,000 yuan just for this well section. The out-of-hole bit was in great condition with minimal blade wear, and it can be reused later. The cost-performance ratio is truly outstanding. Hainaisen's technical team was also on-site promptly, providing practical advice on bit selection and drilling parameter optimization. We will definitely prioritize their bits for future wells in our block."
Supervisor Wang of Party A (Feedback Summary)
"Well Su 75-70-17X is a key development well in the block with tight drilling cycle requirements. The Yanchang Formation section has always been the critical bottleneck for our construction schedule. Hainaisen's SD9633 PDC Bit exceeded our expectations significantly. The remarkable ROP improvement and one-trip completion of the target footage helped us secure the construction period smoothly. Meanwhile, the bit's high durability fully met our cost reduction and efficiency enhancement requirements. We will promote the application of this bit model across the entire block and establish long-term cooperation with Hainaisen."
About Hainaisen Petroleum
Shaanxi Hainaisen Petroleum Technology Co., Ltd. is a professional enterprise engaged in R&D, production and technical services of oil drilling bits in China. Its core products include PDC bits, roller cone bits, diamond composite cutters and supporting drilling tools. The company focuses on providing customized rock-breaking solutions for major oil and gas fields in China.
Relying on independent R&D bit design and simulation platforms, Hainaisen offers accurate bit selection, on-site technical support and personalized customization services based on the geological characteristics of different blocks and formations. Its products have been widely applied in major domestic oil and gas fields such as the Ordos Basin, Tarim Basin, Sichuan Basin and Bohai Bay Basin, serving over a thousand oil and gas wells and gaining consistent recognition from major drilling companies and Party A units.
For more bit products and customized solutions, please visit the official website: https://www.hnsdrillbit.com
Note
All data in this case study are derived from on-site operational records and are traceable. For bit selection schemes of similar formations in the same block, please contact Hainaisen's technical team through the official website to obtain exclusive services.
