| Recently, the metering method of well production in domestic oil fields is mainly to deliver the oil from each well to a metering station for centralized measurement. With the characteristics of many application devices, complex craftwork and large investment, the method cannot meet the requirements of oilfield digitalization, information and automation. the output metering methods of oil well commonly used in our country, are that several wells output in a range was transported to a metering station or test station nearby, and it is re-transported to the oil processing or storage station far-away. In this case, the indicator diagram measure oil technology doesn’t lay pipelines and less investment, also can meet the real-time requirements of continuous real-time automated measurement. But indicator diagrams measure oil technology is still in the early stages of the research, the measuring accuracy and reliability cannot meet the requirements of oil field; Besides, the software which applied to some oil fields is only suitable for vertical Wells, little suitable for deviated well. This paper studies the indicator diagram measure oil technology, the main work is as follows:This paper researches composition of pumping unit well system and dynamic characteristics of sucker rod string, introduces the operation principle of pumping unit and oil-well pump, and explains the geometrical characteristics of theoretical and fault indicator dynamometer, the surface dynamometer card is used as the boundary condition, establishes the prediction model of dynamic behavior of rod string model, and uses finite difference to solve this equation, deduces pump dynamometer card, it lays down the foundation of calculating well production.It is the key of the indicator diagram measure oil technology to determine effective plunger stroke. To determine the plunger effective stroke, the work situation of pump should be known firstly. On the basis of previous studies, this paper analyzes the geometric features of the dozens of fault indictor diagram, transforms theoretical indicator card which under the static load to pump’s theoretical indicator card, as standard indicators which contrasts with fault indictor diagram; also establishes calculation model of the pump characteristic curve, as one of diagnosis rules, use these to diagnose the down hole condition.The paper researches the relationship between pump dynamometer card, opening and closing of the valve position and the effective stroke of the plunger with the pump dynamometer data, and establishes calculation model of the pump characteristic curve, finds the two largest curvature changes point in the high, low load, gets the valve opening and closing point, so as to determining effective plunger stroke.Due to the clearance between plunger and pump barrel dropping out, according to the analysis of different literature, putting forward calculating the clearance between plunger and pump barrel leakage equations. The mixed liquid in the tubing is compressed, after the liquid arrived wellhead, the gas dissolved in the liquid will separate out, so the discharging liquid of underground is not equal to the ground production. This paper presents the method for calculating the volume coefficient of mixture under pump discharge pressure to convert the ground liquid production. Finally, the paper developed the software of indicator diagram measure oil, and take ten wells of White Leopard operating area of the Seventh Oil Production Plant of Changqing for example, elaborated the pump diagram conversion process, the calculation of plungers effective stroke, fault diagnosis and the oil well production, compares with the measured liquid production of ten wells in different periods and computing the measured well production compared to the obtained results,relative error is about8.3%,the proportion of wells which relative error less than10%are about70%, can basically meet the accuracy requirements which measuring single well production. |
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