What is the Best Logging Memory Unit Technique？

Logging Memory Unit is the downhole measurement tools that integrate sensors, data acquisition circuits, large-capacity memory and batteries.

This "memory first, readout later" working mode enables it to break away from the reliance on traditional cables and become a key technology to replace conventional cable logging in complex well conditions such as horizontal wells and long-displacement wells. It is usually sent into the well by means of drill pipes (either along with the drill or conveyed through drill pipes) or steel wires, etc.

The "best" Logging Memory Unit technology depends on specific operation goals, well conditions and budgets. Different technologies have their own advantages and limitations in different scenarios.

Technology can be summarized from two aspects: advantages & limitations

◆ Advantages of Logging Memory Unit

Cable-Free Operation, Good applicability

It does not require cables or ground cable car systems, making it easy to apply to horizontal Wells, long-displacement wells, multi-branch wells, etc. where cables cannot be effectively lowered or the risks are extremely high.

High Reliability & Data Security

The complex cable connections have been eliminated, reducing the number of system failure points. It adopts a sturdy and durable design, capable of withstanding the harsh environment of high temperature, high pressure and strong vibration underground. Once data is stored, it is not easy to be lost and has high security.

Cost-Effective

The equipment is relatively simple, the operation process is simplified, and it takes up less time from the drilling rig. Especially for offshore operations, it can save expensive daily ship charges, and the overall cost is lower than that of cable logging.

High Data Quality

It is equipped with a large-capacity built-in memory, which can achieve full-process and high sampling rate measurement. The data density and accuracy recorded are very high, providing a solid foundation for fine formation evaluation.

Flexible Operation

It can be combined with various modes such as logging while drilling, pipe conveying logging, and wire operation, to meet different engineering requirements

◆ Limitation of Logging Memory Unit

The Data is Not Real-Time

The biggest disadvantage. It cannot transmit data back to the surface in real time like cable logging or measurement-while-drilling, and thus cannot provide drilling engineers with immediate decision-making basis. It can only be analyzed after the fact.

Case Name: Application of Storage Logging While Drilling for Horizontal Wells in a Shale Gas Block

Background: In a certain shale gas block in southwest China, a large number of horizontal Wells need to be drilled to develop reservoirs. The geological structure in this area is complex, and the wellbore trajectory is tortuous. It is extremely difficult, risky and the cost is hard to control to use traditional cable logging.

Solution: Adopt logging while drilling technology and incorporate the Logging Memory Unit as part of the Logging while Drilling tool string. During the drilling process, real-time data is transmitted back to the surface via drilling fluid pulses for initial steering decisions. Meanwhile, the storage short section synchronously records all the original data including natural gamma, resistivity, neutron porosity, rock density, etc. throughout the entire process underground, and the sampling rate and accuracy of the recorded data are higher than those of the real-time transmitted data.

Process & Result:

◆ After drilling is completed, lift the drill and remove the BHA (Bottom drill assembly) with this tool.

◆ In the ground laboratory, complete high-precision logging curves were obtained by reading the data in logging memory unit through dedicated equipment.

◆ These data are used for detailed formation evaluation: accurately dividing reservoir thickness, calculating key parameters such as porosity and gas saturation, and precisely identifying "sweet spot" areas (high-quality reservoirs rich in gas).

◆ Based on the precise depth and formation information provided by the stored data, it offers a crucial design basis for the subsequent fracturing and completion operations, ensuring that the perforation clusters are precisely located in the optimal layer section and significantly increasing the production of a single well.

Case Value:

This case typically demonstrates the core role of memory-based logging in unconventional oil and gas development. Not only has it successfully obtained high-quality data in complex-structured Wells, but its backup record function also ensures the integrity of data when real-time transmission signals are poor, making it an indispensable part of the project's success.

Logging Memory Unit is key tools that modern logging technology has developed to meet the demands of complex oil and gas reservoir development. Through the innovative design of "cable-free" and "downhole storage", it has broken through the physical limitations of cable logging and greatly expanded the application scenarios of logging technology.

Despite it is non-real-time shortcoming, the advantages in improving operational efficiency, reducing operational risks and costs are irreplaceable. It has become a standard configuration and success guarantee in shale gas, tight oil development, offshore drilling and complex structure well operations. As battery technology, memory capacity and the seismic and heat-resistant technology continues to progress, the performance of the storage type tool will further enhance, in the future play a more important role in oil and gas exploration and development.

There is no absolutely unique "best" technology-only the one that is "most suitable." The key to selection lies in comprehensively evaluating well depth, well type, temperature and pressure regimes, required logging parameters, operational timeline, and cost, so as to match the optimal memory-tool solution.

Welcome to contact us to learn more about our tools via e-mail info@a-oneoil.com