Tag Archives: газожидкостная смесь
One of the most important factors, which define the efficiency of sucker rod pump operation, is the filling coefficient of rod pump. The dominant influence on the rate of filling of liquid of the rod cylinder exerts the gas content in the well output and also the presence of the volume, which is placed between suction and discharge valves of the pump in the extreme bottom position of plunger and named as harmful (dead) space of sucker rod pump.
In the paper the processes, which occur in the under–plunger space of rod pump during pumping of gas–liquid mixture, are considered and the influence of the volume of dead space on the character of these processes is estimated quantitatively. The analysis of the known models is presented, which describe the hydraulics of sucker rod pump, and a model is proposed, which accounts for the processes of mixture compressibility in the under–plunger space and the equilibrium processes of gas dissolution and extraction from oil in details. On the base on the constructed mathematical model the method of estimation of limits of possible volume of dead space change is proposed, which allows to keep the filling coefficient value close to the maximum level at given conditions.
MATHEMATICAL SIMULATION OF LIQUID-GAS MIXTURE SEPARATION IN A WELL AFTER FORMATION FLUID FLOW SHUT-OFF
Shut-off of fluid recovery from one of formations at simultaneous selective-zone well operation leads to a natural process of liquid-gas mixture separation. Water holdup in a well after complete separation makes possible to estimate water cut of the blocked formation. This method has advantages over other techniques because provides acquisition of data on water cut for each formation individually, it is characterized by short-term effect because of fast liquid-gas mixture separation and by accuracy due to performance of measurements in close proximity to a formation. For this reason simulation of separation process in an interval from a suction pipe to borehole bottom becomes actual.
After fluid movement stop in “pump suction” interval one can consider process of coarser-grained oil-in-water emulsion separation. It follows that time of complete separation depends on disperse phase size (oil droplets or gas bubbles) and difference in water and oil density. That is why movement of oil and gas bubbles in relation to a fixed water column according to Stokes’ law is used as a movement model when simulating.
From simulation results the following characteristics of phase distribution in a borehole are determined by means of application program package “Matlab” (density, pressure, phase concentration in mixture). These characteristics show the following:
methods sensitive to changes in medium density are the most suitable for determination of phases interface limits;
in case of use of geophysical sensors for definition of phases interface limits with help of a model it is possible to calculate a required quantity of these sensors for estimation of water cut with prescribed accuracy
the model provides solution for various inverse problems connected with mixture separation in a well.
Methods, providing a normal operations mode of gas-liquid mixture (GLM) flow at oil dehydration facilities (ODF) of Arlan fields JSC “ANK “Bashneft” are shown in the article. Based on researches of GLM flow modes, delivered in works of many authors, a number of recommendations are developed on the pipeline design to provide a normal operations flow mode in a suction of multiphase pumps, running at ODF. The analytic solution of the scientific problem is worked out, connected with the selection of a pipeline diameter to provide a normal operations flow mode of GLM, as a result the algorithm of pipeline geometry selection is proposed in base of a lateral pressure gradient. Technical tools are proposed to solve the problem of gas caps passing through a multiphase pump, which realize a forced blending of pumping GLM stratified structure.
The determination of current gas-liquid mix stream mode at the pipeline in oil and petroleum gas gathering system of JSC ANK «Bashneft» on Arlan group of oilfields
In the article JSC “ANK “Bashneft” gathering system of oil wells production with the water dump on preliminary sewage disposal plant operation is considered. Features of exploitation ofequipmentin JSC ANK «Bashneft» oil and petroleum gas gathering and transportation system on Arlan group of oilfields are presented. Factors negatively influencing work of the multiphase screw pumps in structure of preliminary sewage disposal plant operation are marked. The possible current modes of gas-liquid mix are analyzed. The calculation methods of current modes of gas-liquid mix,the results of forecasting and the calculation of a gradient of pressure in structure of preliminary sewage disposal plant operation are defined by Beggs and Brill methodfor the considered equipment arepresented.