Microseismic event back-azimuth is an indispensable parameter for source localization in downhole microseismic monitoring, and the accurate orientation of horizontal components seismic receivers vital reliably determining back-azimuth. Variation monitoring data quality may jeopardize accuracy receiver which will further affect estimation. To mitigate this issue, we proposed a new probabilistic ...

We show that the two-point cross-correlation of potential-field recordings is proportional to the Green’s function between the two points. This holds under the condition that spatially and temporally uncorrelated quasi-static noise sources exist throughout the volume. Natural fluctuations, such as thermal noise, may occur that satisfy the necessary conditions. When these fluctuations are random...

This paper details the online-identification-based adaptive design of a stick/slip minimization algorithm and top-drive servo control for Rotary Steerable System (RSS) directional drilling tools. Stick/slip in this context refers to the downhole angular velocity variation of the bit about a nominal value. The basic pole placement controller designs are SISO linear but recursively evaluated base...

This paper describes the development of a Retrievable Subsurface Accelerometer (RSA) for the NSF George E. Brown, Jr., Network for Earthquake Engineering Simulation (NEES) project at UCLA. The RSA was developed to obtain subsurface vibration data during forced-vibration experiments and aftershock events. The RSA can be rapidly installed using a CPT truck and subsequently retrieved using structu...

Fault diagnosis of downhole traction robot has characteristics special mechanical structure, complicated working condition and lack research data. In this paper, a method fault analysis tractor hydraulic system based on model is presented. The failure mode mechanism key components in telescopic are analyzed. proposed the mathematical component. Based AMESim, established, single multi-fault simu...

The sealing performance will directly affect the operation of downhole robot under HTHP condition. Traditional analysis methods are that temperature and pressure is loaded respectively. This can not really evaluate performance. Besides, simulation process is: Step 1: pre-compress O-ring to produce contact force. According pressure, select compression ratio calculate displacement slip ring. 2: l...