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Objective The supply and sales difference has always been a key point in the management and control of LNG filling stations. Reducing the supply and sales difference of LNG filling stations, especially inefficient LNG filling stations, is of great significance for cost control. Methods According to the actual production and operation status of the station, the specific reasons for the supply and sales difference of LNG filling stations are comprehensively analyzed from the aspects of sales measurement, trade procurement, unloading process and storage. For some factors that enlarging supply and sales difference, the targeted control measures shall be taken from the aspects of gas source procurement, process pipeline design, thermal insulation construction, submersible pump installation, tank release control and station construction mode, etc. Results Through the measurement of practical data after the process transformation and the refined management of production and operation, the supply and sales difference of LNG filling stations has been effectively reduced. Conclusions In the initial design stage and actual operation and management stage of LNG filling stations, we should confirm the station construction standard and strengthen the management and control of LNG filling stations to reduce supply and sales difference according to characteristics of LNG properties, so as to improve the profit of LNG filling stations. [ABSTRACT FROM AUTHOR]

Objective For the gasification station or gas filling station that uses LNG as the gas source, due to the current LNG unloading process, after the unloading of LNG tanker, there is still a certain amount of paid but unusable BOG in storage tank. In view of this common problem, an effective method for recovering BOG is studied. Methods Taking a gasification station as an example, by calculating the recoverable BOG amount in the LNG tanker storage tank, combined with the recovered BOG state parameters, the unloading and operation process flow of the gasification station, the corresponding process transformation scheme is formulated. Results The operation conditions of the main equipment to be selected are simulated. The state diagram of the exhaust capacity and power changing of the single-stage and two-stage compressors with time, and the state diagram of the BOG pressure and margin changing in the tanker with time are drawn. The efficiency of the equipment to be selected is compared visually. Conclusions In the transformation scheme of LNG tanker BOG recovering process in the gasification station, the selection of two-stage low-temperature compressor can reduce the emission and the unloading loss of tanker effectively, which has more advantages. [ABSTRACT FROM AUTHOR]

Chuanshen 1 well, which is an ultra-deep prospecting well, has five-spud section drilled with the depth of 8 120 m. The fifth spud liner cementing confronted hash conditions such as ultrahigh temperature, ultra-high pressure, small annular space, great risk of gas channeling etc. Besides, the request of long term integrity and pack-off capability is higher for the cement sheath during production stage. A system of elastic anti-gas migration latex slurry is established in accordance,with the research of relationship between compressive strength of cement stone and dosage, particle size of silica sand, and with the research of influence on mechanic property by function material. The cement slurry system has stable performance, API Water loss is 18 mL, anti-channel coefficient SPN is 0. 89 elasticity, modulus is ·1. 8 GPa, permeability is 0.10 X 10³ μm², high-temperature settling stability is 0.01 g/cm³, and the compressive strength of 2,1 h is 16. 3 MPa. The cement system is successfully applied in super-deep small annular space liner cementing of Chuanshen 1 well combined with other technological measures, the cementing quality is excellent. [ABSTRACT FROM AUTHOR]

The self-made simulation device was used to simulate pigging referring to oilfield technological process. The influence of pigging and inhibitor injection on the corrosion of 20# steel in simulated liquid of pipeline was analyzed by weight-loss method and corrosion electrochemical method. The results show t hat t he amount of liquid and solid deposit on the surface of 20# steel sample are reduced after pigging with a 3% interference cup pig, and the corrosion rate is significantly reduced. When t he corrosion inhibitor is added into the simulated solution or the sample is prefilmed with inhibitor, the inhibitor molecules will act on the surface of carbon steel to form a layer of corrosion inhibition film, which effectively hinders the direct contact between the sample and corrosion medium. After pigging combined with corrosion inhibitor pre-film, the corrosion rate is reduced to 0. 029 mm/ a, which has a good protection effect on carbon steel. [ABSTRACT FROM AUTHOR]

There are security risks with pressurized workover treatment and formation pollution risk with conventional killing well fluid. This paper developed a controllable crosslinking temporary plugging rubber plug for killing well which take composite modified vegetable gum as the thickening agent, organic complex compound slowly releasing center ions as crosslinking agent, influence the release of center ionic of crosslinking agent through inhibitor, and indirectly control the crosslinking time through effecting ion release. The temporary plugging rubber plug has low viscosity at room temperature (≤36 mPa·s,1 h), can pump injection easily, create the gel rapidly in the wellbore condition, then form a solid with very high intensity and viscoelasticity. The initial viscosity of it can reach more than 30 000 mPa·s at 120 °C, keep the state of semi-solid to ge after 48 h aging. It has good viscoelasticity, good sealing effect to the wellbore, and can be broken down within 1-4 h after contact with the blocking fluid, so it can avoid the formation damage. This technology has been applied in the high temperature sulfur well with pressure switch valve operation, the oil pressure is from 59 MPa down to 29 MPa after 4 h pump injection temporary plugging rubber plug, the subsequent replacement of main control valve with pressure is success, and the fluid flow-back is smoothly after broken down(viscosity≤5 mPa ·s), so the oil pressure recovery is quickly. [ABSTRACT FROM AUTHOR]