Introduction

In the Oil & Gas Industry new, high potential wells are often ‘choked’ due to production constraints. Instead of wasting this energy by ‘choking’ a Gas Ejector can be simply installed to boost production from marginal wells.

Gas Ejector installed on North Sea gas rig

Principle of Operation

Gas Ejectors have no moving parts and use high pressure gas to compress low pressure gas to an intermediate level.

Application

On a North Sea gas field a small satellite reservoir had been developed from the main existing production facilities. Flow from the satellite Well was restricted during the winter months, when demand was high, due to increased back pressure on the facilities generated by the flow from the main field in the export pipeline . If the summer Flowing Tube Head Pressure (FTHP) could be maintained throughout the winter, gas sales could be increased. The main field Wells produced a FTHP of 140 barg, choked down to 100 barg for export.

The LP satellite Well could produce 1.6MMscm/d at the Summer FTHP (80 Barg) dropping back to 1.3MMscm/d in the Winter (100 Barg).

Solution

This application was ideal for a Gas Ejector as the 40 barg excess pressure energy, normally wasted through choking, was available to entrain and compress the LP gas. With the Gas Ejector installed using only 2.8 MMscfm/d of HP gas the Well can now produce 1.6 MMscm/d all year round and in the first month of operation an extra £300,000 sales revenue was earned. In the first month of operation the Transvac Gas Ejector generated £300,000 extra revenue and has performed above it’s original design specification.

Design

Transvac designed and manufactured the Gas Ejector in accordance with ASME VIII Div 1, with full non-destructive testing and with ANSI 1500 Lb rated Flanges. All Transvacs’ design and manufacturing processes are quality assured and certified to BS EN ISO 9001.

Advantages Increased production rates Low cost with short payback Improved pressure for pipeline transport Low noise levels Reliable and simple to operate Robust construction with no moving parts Custom designed to suit field operating conditions

Jet Compressor installed on North Sea gas rig