Automating Remote Gas Wells, Compressors And Processing Plants
Authors: Davis Glen R. 
Published: December 2007

Combinations of radio and radio-telephone lines wereused to automatically control gas wells, compressors andgas processing plants. The gas wells can be individuallyand collectively controlled to keep gas processingfacilities at capacity operation regardless of variations inthe supply of gas from wells. Alarm systems transmit signalsby radio to manned stations when a compressor or processingtemperatures, operating pressures, meter differentialsand engine speeds are telemetered on command from theinstallation to central plants as far away as 70 miles. These installations have been outstandingly successful, and have shown that proper design and careful selectionof quality components will allow remote monitoring andcontrol of facilities.

Introduction

In the Permian Basin of West Texas and New Mexico, several gas-gathering systems have been built aroundcentral plant facilities which serve as communications, operations and maintenance centers. Each plant systemcovers several hundred square miles. Many of the oil andgas fields in the West Texas-New Mexico area are toosmall to justify conventional gas-processing plants withtheir normal personnel complements. Studies indicatedthat processing isolated gas supplies could only bejustified if the gas were compressed in unattended stations inthe remotely located field and transported to a centralprocessing plant. Unattended operation of gas-engine andelectric-motor driven compressor stations, as well asprocessing facilities for liquid hydrocarbon extraction andgas dehydration, is both practical and economical. This paper discusses the several features which makeunattended operation of such facilities possible anddescribes several gas processing plant systems utilizingthese features. Although not covered in the present paper, unattended gas-treating facilities for hydrogen sulfide andcarbon dioxide removal have also been designed and arebeing successfully operated. The authors draw upon theirexperience to formulate recommendations for others.

Radio Systems

The Federal Communications Commission hasdesignated certain radio frequencies for use by industry. The same frequency may be used by several base-stationtransmitters, and by more than one company orindividual. The FCC grants approval for each specifictransmitter. Sufficient geographical separation is maintainedbetween transmitters on the same frequency to minimizeinterference. We utilize four different carrier-wavefrequencies in the 72 to 76 megacycle range fortelemetering and control purposes. Each RF carrier wave isfrequency-modulated by imposing one or more discreteaudio-frequency tones upon the carrier wave. Radioreceivers, by the use of decoding networks, extract theaudio-frequency tone or tones from the incoming RFsignal. The presence of tones, their frequency andduration constitute the intelligence being communicated.

Unattended Booster Stations

It is frequently economical to operate unattendedcompressor stations picking up small quantities of gasproduced in outlying fields and transporting to a centralprocessing area. For compressors to operate unattended, it is essential that machinery safeguards be built into thecompressor stations so that individual compressor unitswill be shut down whenever malfunctions develop whichwould endanger their safety. Both gas-engine and electric-motor driven stations arebeing operated. The electric-motor driven stationsrepresent the ultimate in automatic control for remoteoperation. They require less maintenance than their gas-enginedriven counterparts and have a higher on-stream factor. Electric power, however, usually costs more than naturalgas fuel. In the absence of operators, some method must befound, if a high on-stream factor is to be realized, toalert personnel at a central location whenever acompressor goes off the line so that corrective measures may bepromptly taken to return the unit to service. Telephonelines, where already existing, are satisfactory andinexpensive. Where telephone lines do not already exist, radioshould always be considered as an alternate-even forshort distances.

Unattended Processing Facilities

Glycol gas dehydration units can often be operatedon an unattended basis. Each isolated booster stationdiscussed in this paper incorporates gas dehydration.

JPT