Coreless Electromagnetic Coupling-Based Drillstem Telemetry Using Dual Electronic Gauges

Abstract

A coreless electromagnetic coupling-based telemetry system for well-test data involving a full-bore drillstem test apparatus has been developed. This system allows the retrieval of formation pressures and temperatures above and below a tester valve by means of a wireline-conveyed electronic gauge and a permanently installed gauge. A wireline-deployed coreless electromagnetic proximity sonde is put into the well to transfer the data using time-division frequency transmission technology in the "Synchronization-Pressure-Low-Temperature-Low" mode on a single-core wired-armored cable. The coded pulse data are modulated on DC power signals. The surface processor uses a double-counter synchronization method to measure signal frequencies to eliminate ±1 most significant bit (MSB) error. Then a simplified algorithm is proposed, based on least-squares curve fitting and dimensionreduction methods, for computing actual temperatures and pressures for analysis of well-testing data. The proposed system is calibrated for temperatures up to 125°C and pressures up to 70 MPa with a pressure accuracy of 0.1% full scale (FS) and temperature accuracy of ±0.5°C. This approach combines the advantages of drillstem testing and wireline formation testing and has been successfully applied to onshore well testing.

Characteristics Analysis of Joint Acoustic Echo and Noise Suppression in Periodic Drillstring Waveguide

“…Since the downward moving noise ( ) disturbing acoustic signal extraction is a mixed signal of the noise and the data due to multiple reflections, the following result can be achieved by (2) to minimize the amount of noise being transmitted upward towards the surface:…”

“…In the oil industry, measurement-while-drilling (MWD) surveying is of great importance for the successful completion of the drilling process [1]. Such information, if transmitted to the surface, can be used to optimize the drilling by adjusting the direction of drilling and to understand downhole formation conditions in real time [2]. These useful data related to subsurface earth formation can be derived in a number of ways [3].…”

Experimental Analysis of Acoustic Transmission Characteristics along the Periodic Simulated Drillstring

“…The common remote telemetry methods mainly include electronic wireline telemetry, mud pulse telemetry, extremely low frequency electromagnetic (EM) telemetry and drillstring acoustic telemetry [2]. The electronic wireline telemetry system utilizes cables for transmitting information from downhole to the surface.…”