BS EN 1918-5:2016 pdf free.Gas infrastructure —Underground gas storage Functional recommendations forsurface facilities.
BS EN 1918-5 The main equipment that may be required for both the withdrawal and the injection operations of gas storagefacility is described below.
Where no specific mention of LPG or natural gas is made, the following statements refer to both.3.2 Underground gas storage
Overview and functionality of underground gas storage
EN1918 covers storage of natural gas,Compressed Natural Gas (CNG) and Liquefied Petroleum Gas (LPG).Because of the relevance of underground gas storage of CNG the major part of this introduction is related to thestorage of natural gas.
The underground gas storage (UGS) is an efficient proven common technology and is in use since 1915.UGSbecame an essential indispensable link in the gas supply chain for adjusting supply to meet short-term andseasonal changes in demand.
Natural gas produced from oil and gas fields is increasingly being used to supply energy requirements.As thegas supply from these fields does not match with the variable market demand, natural gas is injected intosubsurface storage reservoirs when market demand falls below the level of gas delivery or if there is aneconomic incentive for injection. Gas is withdrawn from storage facilities to supplement the supply if demandexceeds that supply or withdrawal is economically attractive.
The primary function of UGS is to ensure that supply is adjusted for peak and seasonal demand.Apart from this,the storage facilities can provide stand-by reserves in case of interruption of the planned supply.IncreasinglyUGS is applied for commercial storage services.
UGS are naturally or artificially developed reservoirs respectively artificially developed caverns in subsurfacegeological formations used for the storage of natural gas (or LPG).A UGS consists of all subsurface and surfacefacilities required for the storage and for the withdrawal and injection of natural gas (or LPG).Severalsubsurface storage reservoirs or caverns may be connected to one or several common surface facilities.
The suitability of subsurface geological formations have to be investigated individually for each location, inorder to operate the storage facilities in an efficient, safe and environmentally compatible manner.
In order to construct a storage facility,wells are used to establish a controlled connection between thereservoir or cavern and the surface facilities at the well head. The wells used for cycling the storage gas arecalled operating wells. In addition to the operating wells, specially assigned observation wells may be used tomonitor the storage performance with respect to pressures and saturations and the quality of reservoir wateras well as to monitor any interference in adjacent formations.
For the handling of gas withdrawal and gas injection, the surface facilities are the link between the subsurfacefacilities and the transport system, comprising facilities for gas dehydration/treatment, compression, processcontrol and measurement.
Gas is injected via the operating wells into the pores of a reservoir or into a cavern, thus building up a reservoirof compressed natural gas (or LPG).
Gas is withdrawn using the operating wells. With progressing gas withdrawal, the reservoir or cavern pressuredeclines according to the storage characteristic.For withdrawal, re-compression may be needed.
See Figure 2 for the injection mode and withdrawal mode.
The working gas volume can be withdrawn and injected within the pressure range between the maximum and minimum operating pressure. In order to maintain the minimum operating pressure, it is inevitable that asignificant quantity of gas, known as cushion gas volume, remains in the reservoir or cavern.BS EN 1918-5 pdf download.