Integrated construction technology for natural gas gravity drive and underground gas storage

Based on the mechanisms of gravity displacement,miscibility,viscosity reduction,and imbibition in natural gas flooding,an integrated reservoir construction technology of oil displacement and underground gas storage(UGS)is proposed.This paper systemically describes the technical connotation,site selection principle and optimization process of operation parameters of the gas storage,and advantages of this technology.By making full use of the gravity displacement,miscibility,viscosity reduction,and imbibition features of natural gas flooding,the natural gas can be injected into oil reservoir to enhance oil recovery and build strategic gas storage at the same time,realizing the win-win situation of oil production and natural gas peak shaving.Compared with the gas reservoir storage,the integrated construction technology of gas storage has two profit models:increasing crude oil production and gas storage transfer fee,so it has better economic benefit.At the same time,in this kind of gas storage,gas is injected at high pressure in the initial stage of its construction,gas is injected and produced in small volume in the initial operation stage,and then in large volume in the middle and late operation stage.In this way,the gas storage wouldn’t have drastic changes in stress periodically,overcoming the shortcomings of large stress variations of gas reservoir storage during injection-production cycle due to large gas injection and production volume.The keys of this technology are site selection and evaluation of oil reservoir,and optimization of gravity displacement,displacement pressure,and gas storage operation parameters,etc.The pilot test shows that the technology has achieved initial success,which is a new idea for the rapid development of UGS construction in China.

Experimental study and field application of appropriate selective calculation methods in gas lift design

The most common way to achieve an enormous production rate of a reservoir is to increase drawdown pressure during the production procedure by decreasing the bottom-hole pressure.This process was done by artificial patterns like a gas lift.Nowadays,most of the wells worldwide due to years of production and reducing the amount of energy which was supplied by natural drive mechanisms are being placed on artificial lift methodologies.Hence,the number of wells that used this method will continue to increase.The primary purposes in the gas lift design of a wellbore are to determine the proper depths and the location of valve installation,select appropriate flow regime during the pipeline and calibrate the pressures of the operating and unloading valves.The purpose of this research is to design gas lift system in the oil wells of on the south fields of Iran by considering the maximum production connate water volume of 40 percent and average pressure drop(20-25 psia)throughout the year regarding production continuously or increasing the flow rate of the wells.Therefore,20 wells that their number starts A to T with this locations L280N,W115S and W002S are the candidates for gas lift procedures.Furthermore,the appropriate flow regimes through the well are being studied,and the most proper method for gas lifting and required surficial equipment will be designed for this field.Consequently,due to increasing the volume of gas and connate water among the production after gas lifting,fundamental changes on the equipment,flow regimes and gas lift system are being proposed that production will be done by proper engineering method.In the well gas lift design,Beggs&Brill Revised method is being selected for hydraulic calculation of pipeline flow due to low errors.