Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates mate...Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates material balance principle and the concept of material balance pseudo-time proposed by Blansingame. With daily production data of gas well, it could be used to calculate OGIP, current formation pressure, permeability, skin factor, to identify complex geologic boundaries, to determine whether drainage boundary has been reached, to calculate drainage area and drainage radius for single well and to predict performance. It has been extensively employed in more than ten low-permeability gas fields. It proves that most problems in performance analysis for low permeability gas reservoirs could be solved by this method. Field practices show great economical benefits could be achieved by employing this method in gas field development.展开更多
In a low permeability reservoir, the existence of a moving boundary is considered in the study of the transient porous flow with threshold pressure gradient. The transmission of the moving boundary directly indicates ...In a low permeability reservoir, the existence of a moving boundary is considered in the study of the transient porous flow with threshold pressure gradient. The transmission of the moving boundary directly indicates the size of the drainage area as well as the apparent influences on the pressure behavior. The nonlinear transient flow mathematical model in which the threshold pressure gradient and the moving boundary are incorporated is solved by advanced mathematical methods. This paper presents some new analytical solutions describing the pressure distribution at a constant rate and the production decline in a constant pressure production with the boundary propagation. It is shown that the greater the threshold pressure gradient, the slower the transmission of the moving boundary, the larger the pressure loss will be, and there is no radial flow in the middle and later phases of the wellface pressure for a well at a constant rate. We have the the maximum moving boundary at a specific drawdown pressure for a low permeability reservoir The greater the threshold pressure gradient, the smaller the maximum moving boundary distance, the quicker the production decline for a well in a constant pressure production will be. The type curve charts for the modern well test analysis and the rate transient analysis with a moving boundary are obtained and the field test and the production data are interpreted as examples to illustrate how to use our new results.展开更多
Changqing old oilfield Jurassic reservoir's average calibration recovery is 24.7%,with geological reserves recovery of 16.6%,water cut of 65.2%.And most of Jurassic reservoirs are in the middle and later field lif...Changqing old oilfield Jurassic reservoir's average calibration recovery is 24.7%,with geological reserves recovery of 16.6%,water cut of 65.2%.And most of Jurassic reservoirs are in the middle and later field life,part of them has entered the high water cut and high recovery stage.Traditional water flooding way for improving oil recovery becomes more difficult,and new method has to be considered.Maling oilfield BS district is a typical representative,with high water cut of 90.8%,high recovery percent of 26.1%and low oil recovery rate of 0.25%.To explore the new way to improve oil recovery,the polymer and surfactant(SP for short)important pilot test has been developed.The low permeability reservoir indoor core data in high water cut stage and inspection well results indicate that the reservoir permeability,pore combination characteristics and pore type changed greatly after long-term water flooding development.These changes bring more difficulties to the continue development,especially the high injection pressure,which can cause other problems for well pattern infilling and EOR.This paper takes the high injection pressure problem of Maling BS district Jurassic reservoir for example,analyzes the physical property change law on the following aspects:the development mode in the past,core analysis,formation sensitivity,interstitial matter,well test interpretation results,in order to help to further effective development and provide important parameters for tertiary oil recovery technique for similar reservoirs and others.展开更多
The Fang-48 fault block oil reservoir is an extremely low permeability reservoir, and it is difficult to produce such a reservoir by waterflooding. Laboratory analysis of reservoir oil shows that the minimum miscibili...The Fang-48 fault block oil reservoir is an extremely low permeability reservoir, and it is difficult to produce such a reservoir by waterflooding. Laboratory analysis of reservoir oil shows that the minimum miscibility pressure for CO2 drive in Fang-48 fault block oil reservoir is 29 MPa, lower than the formation fracture pressure of 34 MPa, so the displacement mechanism is miscible drive. The threshold pressure gradient for gas injection is less than that for waterflooding, and the recovery by gas drive is higher than waterflooding. Furthermore, the threshold pressure gradient for carbon dioxide injection is smaller than that for hydrocarbon gas, and the oil recovery by carbon dioxide drive is higher than that by hydrocarbon gas displacement, so carbon dioxide drive is recommended for the development of the Fang-48 fault block oil reservoir.展开更多
文摘Rate transient method is a recently-developed performance analysis tool specially designed for low-permeability or tight gas reservoirs. This method, theoretically based on pressure transient analysis, integrates material balance principle and the concept of material balance pseudo-time proposed by Blansingame. With daily production data of gas well, it could be used to calculate OGIP, current formation pressure, permeability, skin factor, to identify complex geologic boundaries, to determine whether drainage boundary has been reached, to calculate drainage area and drainage radius for single well and to predict performance. It has been extensively employed in more than ten low-permeability gas fields. It proves that most problems in performance analysis for low permeability gas reservoirs could be solved by this method. Field practices show great economical benefits could be achieved by employing this method in gas field development.
基金supported by the Fundamental Research Funds for the Central Universities,the Important National Science and Technology Specific Projects during the Eleventh Five Years Plan Period(Grant No.2009ZX05009-004-03)
文摘In a low permeability reservoir, the existence of a moving boundary is considered in the study of the transient porous flow with threshold pressure gradient. The transmission of the moving boundary directly indicates the size of the drainage area as well as the apparent influences on the pressure behavior. The nonlinear transient flow mathematical model in which the threshold pressure gradient and the moving boundary are incorporated is solved by advanced mathematical methods. This paper presents some new analytical solutions describing the pressure distribution at a constant rate and the production decline in a constant pressure production with the boundary propagation. It is shown that the greater the threshold pressure gradient, the slower the transmission of the moving boundary, the larger the pressure loss will be, and there is no radial flow in the middle and later phases of the wellface pressure for a well at a constant rate. We have the the maximum moving boundary at a specific drawdown pressure for a low permeability reservoir The greater the threshold pressure gradient, the smaller the maximum moving boundary distance, the quicker the production decline for a well in a constant pressure production will be. The type curve charts for the modern well test analysis and the rate transient analysis with a moving boundary are obtained and the field test and the production data are interpreted as examples to illustrate how to use our new results.
文摘Changqing old oilfield Jurassic reservoir's average calibration recovery is 24.7%,with geological reserves recovery of 16.6%,water cut of 65.2%.And most of Jurassic reservoirs are in the middle and later field life,part of them has entered the high water cut and high recovery stage.Traditional water flooding way for improving oil recovery becomes more difficult,and new method has to be considered.Maling oilfield BS district is a typical representative,with high water cut of 90.8%,high recovery percent of 26.1%and low oil recovery rate of 0.25%.To explore the new way to improve oil recovery,the polymer and surfactant(SP for short)important pilot test has been developed.The low permeability reservoir indoor core data in high water cut stage and inspection well results indicate that the reservoir permeability,pore combination characteristics and pore type changed greatly after long-term water flooding development.These changes bring more difficulties to the continue development,especially the high injection pressure,which can cause other problems for well pattern infilling and EOR.This paper takes the high injection pressure problem of Maling BS district Jurassic reservoir for example,analyzes the physical property change law on the following aspects:the development mode in the past,core analysis,formation sensitivity,interstitial matter,well test interpretation results,in order to help to further effective development and provide important parameters for tertiary oil recovery technique for similar reservoirs and others.
文摘The Fang-48 fault block oil reservoir is an extremely low permeability reservoir, and it is difficult to produce such a reservoir by waterflooding. Laboratory analysis of reservoir oil shows that the minimum miscibility pressure for CO2 drive in Fang-48 fault block oil reservoir is 29 MPa, lower than the formation fracture pressure of 34 MPa, so the displacement mechanism is miscible drive. The threshold pressure gradient for gas injection is less than that for waterflooding, and the recovery by gas drive is higher than waterflooding. Furthermore, the threshold pressure gradient for carbon dioxide injection is smaller than that for hydrocarbon gas, and the oil recovery by carbon dioxide drive is higher than that by hydrocarbon gas displacement, so carbon dioxide drive is recommended for the development of the Fang-48 fault block oil reservoir.
