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1. Industry Background
In directional drilling operations in coalbed methane (CBM) downhole environments, Measurement While Drilling (MWD) and azimuthal gamma ray systems are core equipment for geosteering. They directly determine borehole trajectory accuracy, reservoir encounter rate, and operational costs, and serve as critical technical support for mine gas control and water hazard prevention.
With the continuous advancement of quality and efficiency improvement in the industry, and facing the stringent requirements of complex downhole working conditions, a complete MWD solution with high reliability, high cost-effectiveness, and easy operability has become an urgent industry demand.
2. SK-TensEE System Overview
SK-TensEE is a high-performance complete MWD solution developed by Shenkai for coalbed methane, coal measure gas, and marginal oilfield development. It is specifically optimized for industry pain points, providing strong support for enterprises to conduct directional drilling operations safely, efficiently, and at low cost.
SK-TensEE Complete System Equipment
3. Core Advantages
3.1 High Cost-Effectiveness: Reducing Life-Cycle Cost
Procurement and O&M costs are core elements of cost control in CBM drilling projects. Traditional MWD systems generally have high acquisition costs and continuously escalating maintenance expenses, squeezing project profitability.
SK-TensEE follows a high ROI (Return on Investment) design philosophy, integrating American GE measurement-while-drilling technology with localized engineering design. It lowers procurement thresholds and compresses life-cycle O&M costs, achieving "controllable investment, rapid returns, and O&M savings." Through technological iteration, it can help enterprises reduce comprehensive MWD costs by more than 15%.
3.2 Easy Operation: Quick-Connect Rotary Coupling for Improved Rig-Site Efficiency
Coalbed methane drilling sites have complex conditions in terms of space, personnel, and working conditions. The ease of equipment assembly and disassembly directly affects construction schedule. Traditional MWD equipment requires long connection and testing time, and maintenance is highly dependent on specialized personnel, which both restricts progress and increases downhole operation risks.
SK-TensEE optimizes ergonomics for field scenarios. The tool adopts a quick-install rotary connection structure, enabling rapid assembly, disassembly, and testing. It reduces wear at connection points, lowers operation thresholds, decreases field failure probability, and avoids non-productive time (NPT) caused by schedule delays.
3.3 High-Sensitivity Azimuthal Gamma: Precise Coal Seam Identification
Azimuthal gamma measurement is one of the core geosteering technologies. It identifies lithology and anchors formation boundaries through differences in natural radioactivity, determining the hit accuracy of coal seam targets. In most Chinese coal fields, the gamma contrast between CBM reservoirs and surrounding rock is weak. Coupled with high-temperature, high-vibration downhole conditions, traditional equipment often suffers from insufficient sensitivity, distorted data, and blurred boundary identification, leading to missed thin coal seams and schedule delays.
SK-TensEE is specifically optimized for CBM geology and working conditions with high-sensitivity, high-contrast azimuthal gamma technology. It can precisely capture subtle gamma value variations between CBM reservoirs and surrounding rock. Through algorithm optimization and patented hardware noise-reduction design, lithology interface changes are more pronounced and bed boundaries are clearer, providing accurate basis for drilling operations and effectively improving thin coal seam encounter rate.
3.4 Efficient Decoding & Strong Anti-Interference: Stable Data Transmission
MWD transmits measurement data through the mud pulse telemetry channel. Pump noise, high weight on bit (WOB), and severe vibration can cause traditional equipment to suffer degraded decoding efficiency, packet loss, and data distortion, affecting steering accuracy.
SK-TensEE adopts optimized coding and decoding algorithms, leveraging AI spectrum real-time analysis and adaptive filtering to significantly reduce bit error rates during high-noise drilling. The internal electronic modules use multi-stage shock absorption technology. Under high-vibration conditions, MTBF (Mean Time Between Failures) is improved by 100% compared to conventional equipment, and decoding efficiency is increased by more than 30%
4. Main Technical Specifications
Parameter：Specification
Temperature Rating：150°C / 165°C
Pressure Rating：15,000 psi / 20,000 psi
Vibration Resistance：≥ 30g @ 5–1000 Hz
Mud Pulser：Low-power motor type, 400 hours continuous run per trip
Survey Mode：Supported: dynamic survey, pump on/off dual-mode survey
Measurement Parameters：Inclination, tool face, azimuth, magnetic dip, azimuth gamma, etc.
Downhole Condition Monitoring：Bottomhole temperature, drilling RPM, vibration, shock, stick-slip
Surface Decoding System：Minimum decoding signal: 1 psi; Minimum decoding pulse width: 0.25 s
Remote Transmission：WITS / WITS-MAIL
Downlink Communication：DOWNLINK command transmission supported
HMI：Chinese / English supported
SK-TensEE Intelligent Decoding Software
5. Field Application Case
SK-TensEE adopts a core instrument string combination of "mud pulser + azimuthal gamma + DM + Battery ", with excellent field application performance.
Field Operation Scene
5.1 Well Profile and Operating Parameters
Drilled pace: 1,200–3,826 m; flow rate: 65–68 L/s; mud density: 1.48 g/cm?; sand content:<1%; solids content: 12%. The target zone has complex working conditions. Bottomhole circulating temperature: 92°C. Vibration statistics: <20g accounts="" for="" 50g="">50g accounts for 15%.
5.2 Application Performance
The SK-TensEE tool string demonstrated excellent comprehensive performance across all system modules — downhole operating status, surface decoding performance, tool body condition, and performance parameters, with coordinated operation of all modules on the surface computer system:
l Stable Operation: 224 hours continuous downhole operation without failure, reliable under high-vibration conditions.
l Accurate Decoding: Key metrics such as data decoding quality and confidence performed excellently, with precise measurements.
l Wear & Erosion Resistance: No obvious erosion wear on tool OD barrel under 65–68 L/s high-flow circulation.
l Strong Reusability: All parameters met specifications after tripping out; no maintenance or component replacement required for reuse.
5.3 Application Conclusion
Field applications demonstrate that the SK-TensEE MWD system, under complex working conditions such as high flow rate, severe vibration, and low gamma value CBM formations, possesses comprehensive advantages of stable operation, precise measurement, erosion and wear resistance, and low operating cost.
Field Operation Scene
6. Summary: Tailored for CBM Drilling, Empowering Quality and Efficiency
CBM drilling must simultaneously address complex geological conditions and quality-and-efficiency improvement demands. The SK-TensEE high-performance MWD solution, with its multiple core advantages of high cost-effectiveness, easy maintenance, high-sensitivity high-contrast azimuthal gamma, strong anti-interference capability, and efficient decoding, addresses industry pain points and delivers on the combined value of high performance, low cost, and easy operation.
Whether for SMEs seeking cost control, or for large mining groups requiring intelligent, precise directional drilling operations, this system can provide tailored technical solutions. It helps enterprises reduce comprehensive construction costs, improve operational efficiency, and mitigate downhole engineering risks — providing equipment assurance for safe, efficient, and intelligent development of coalbed methane, CBM, and marginal oilfield drilling projects.
