外文文献及中文翻译accessrelational database大学论文.docx

1、外文文献及中文翻译accessrelational database大学论文Chemical and Petroleum Engineering, Vol. 40, Nos. 1112, 2004COMPRESSORS, PUMPS, REFRIGERATION ENGINEERINGUPDATING PISTON PUMPS FOR OILPRODUCTIONB. S. Zakharov,1 G. N. Sharikov,2and E. G. Kormishin2The three-plunger acid treatment pump SIN32 and the two-cylinder

2、double-acting pump NPTs-32 with four working chambers (for cementing units) have been updated to control pump delivery. The fluid delivery diagrams for pumps of various designs are examined and the test results are reported.In drilling and oil production, single-acting three-plunger (triplex) pumps

3、or double-acting two-cylinder (duplex) pumps are used.In injecting reagents (clay drilling mud, water, cement, acid, etc.) into wells, depending on the technology applied，it is required to inject the fluid in amounts ranging from the maximum to the minimum in a single operation. If the bed accepts t

4、he injected fluid well, it becomes necessary to maximize pump delivery for quick completion of the operation. If on the other hand, the bed does not accept the fluid well, it becomes necessary to reduce pump delivery so as to restrict the injection pressure to the safe limit. At present, because of

5、wear of well (down-hole) equipment, the permissible injectionpressure is not higher than 1015 MPa.The delivery of a piston (reciprocating) or a plunger (displacement) type of pump can be controlled in the following ways: by installing several pumps with identical or different pumping capacities; by

6、changing the drive rotation speed; by using cylinders (plungers) of the required size; by channeling a part of the fluid into a bypass; and by dismounting one or several valves.The first version is used essentially in drilling. In oil production, generally all versions are used either individually o

7、r in some combination.All pumping units designed for injection of various fluids (fluidal materials) for cementing, hydraulic formation fracturing, hydraulic sand-jet flushing of sand bridges, and other flushing operations in oil and gas wells are mounted on the chassis of motor vehicles (trucks), t

8、ractors, caterpillar (tracked) carriers, and specially made carriages.The operating parameters of the pumps (delivery and injection pressure) depend on the power of the drive and maximum and minimum speed of the engine and the pump. The pump delivery can be changed by changing the number of pump str

9、okes without stopping the engine with the help of a gearbox (by gear shifting) and with stopping of the engine by installing cylinders of the required size. Replacement of the cylinders takes a lot of time and is not always possible in a continuous echnological process. In the existing pumping plant

10、s, the delivery variation range is inadequate. At the minimum rotation speed and cylinder diameter, the delivery remains extremely high, and for injecting the fluid into the bed the pressure has to be raised above what is permissible.Assigned by NGDU Zainskneft, kogermet carried out updating of two

11、types of pumps, namely, SIN32 and NPTs-32.In the three-plunger (triplex) acid treatment pump SIN32, for reducing the minimum delivery down to 1.0 m3/h,plungers having a diameter of 125 mm were replaced with plungers having a diameter of 55 mm. As a result, the theoretical pump delivery was reduced f

12、rom 16 down to 3.3 m3/h. Further reduction of the pump delivery was achieved by reducing the rotation speed of the vehicle engine to the possible minimum (500600 rpm).Simultaneously with this, a new design of packing glands (sealing devices) of plungers of the UPN55 type was developed.It was based o

13、n Zakharov mechanical seal 1, which demonstrated high reliability and durability in sucker-rod (oil) pumps. The sealing units and the pistons with a diameter of 55 mm were made for the SIN32 pump by LKAMneftemash in Perm. Its finishing and testing were done by kogermet jointly with NGDU Zainskneft.T

14、he design of the UPN55-type plunger seal is shown in Fig. 1. The combined seal consists of the main threestage mechanical seal 4 and an elastic sealing collar 2. Each stage of the mechanical seal consists of ten rings that are elastically pressed against each other and simultaneously against the plu

15、nger surface. The rings are pressed against theplunger in pairs from the opposite sides. The next pair is turned relative to the preceding one by 90. The rings are pressed in the axial direction by rubber rings of round cross section and in the radial direction, by rubber girdles with eccentric coll

16、ars. The plunger 5 is made of steel 45 and is chromium-plated and the sealing rings are of bronze. Threecartridges with mechanical seals were installed in the housing bore 3 with a clearance that helps self-centering of the seals relative to the plunger. The cartridges are pressed together by a roun

17、d nut 1 through a bushing with the sealing collar 2. There are holes in the housing for injecting oil and draining out the overflow into the receiving (suction) line of the pump.In contrast to the well-known elastic glands, the mechanical seal does not require periodic adjustments and ensures reliab

18、le operation of the assembly over a long period 2. Use of the updated SIN32 pump having a UPN55 type of mechanical plunger seals confirmed that the proposed design operationally fit.From August through December 2003, NGDU Zainskneft carried out seven bottom-hole treatments (BHT) of six wells using t

19、he updated SIN32 pump. Different types of technological operations were carried out in the wells: mud acid BHT, muriatic (hydrochloric) acid BHT, injection of the reagents SNPKh-9021, MIAPROM, and RMD, for which SIN32 and ATs-32 pumping units were generally used. If acid or any other reagent could n

20、ot be forced through (injected) at 1215 MPa pressure, a low-capacity unit was connected with the SIN32 pump. In that case, the injection pressure dropped by 24 MPa。Injection was completed at the third-gear speed of the engine.The NGDU technologists believe that connecting a low-delivery unit with an

21、 SIN32 pump offers the following advantages: possibility for continuous injection of acids and reagents in case of low intake capacity of the bed and for prevention of opening up of the fractures (hydraulic fracturing) of the collector and excessive rise in flow string testing pressure; extended ope

22、rating life of the flow string by virtue of pressure stabilization during injection; and action of the acid throughout the perforation period and more complete reaction with the rock when the acid infiltrates the bed.Since the maximally possible delivery of the SIN32 pump is reduced at least fivefol

23、d, NGDU Zainskneft proposed to perform all BHTs by injecting acids into the bed with the aid of a low-capacity unit and all other operations, with a standard unit. In that case, however, it would be necessary to place in the well, instead of one, two units, which have to be handled，by two teams, i.e

24、., it will entail additional manpower and costs. Moreover, a low-capacity unit is not always fully utilized(does not operate to full capacity) and often stalls.Thus, for a specific size of the cylinder it is necessary to reduce the pump delivery down to the minimum and, consequently,to broaden the r

25、ange of control of the pump capacity toward its reduction while maintaining maximally possible delivery.In multichamber pumps, this issue is resolved by shutting down (disengaging) one or several working chambers.In duplex plunger pumps, disengaging one or two chambers will cause significantly uneve

26、n delivery, hydraulic shocks, disruption of the balance of loads on the drive, and failure of the pump.In double-acting two-cylinder (duplex) pumps having four working chambers of the NPTs-32(9T) type, which are installed, for example, in ATs-32 cementing units, the delivery can be reduced by diseng

27、aging two rod chambers, which is achieved by removing two delivery (pressure) valves (Fig. 2).The delivery of the NPTs-32 type of pump (duplex) having four chambers isQ = 2(2F )Sn,where F is the cross-sectional area of the cylinder with a diameter Dc, dm2; is the cross-sectional area of the rod with

28、 a diameter dr, dm2; S is the stroke length, dm; and n is the number of double strokes per minute.If the delivery (pressure) valves are removed from the rod chambers, the four-chamber pump turns into a two-chamber one with differentially acting cylinders. The delivery of such a pump Q1 = 2FSn.If the

29、 valves from the front chambers are removed, the pump delivery can be determined by the equation Q2 = 2(F )Sn.Reduction of delivery by disengaging the rear (rod) chambers depends on the factor k1 = (2 /F) and by disengaging the front chambers, on the factor k2 = 2 + / (F ). It can be readily seen th

30、at for reducing delivery the front chambers have to be disengaged. However, theory and practice show that disengagement of the rod chambers is more advisable.Thus, in NPTs-32 type of pump having cylinders of 90, 100, 115, and 127 mm diameter and rods of 45 mm diameter the delivery can be reduced 1.7

31、51.87 times by removing the valves from the rod chambers. At low loads (pressure dropnot more than 15 MPa and minimal delivery), the engine of the motor vehicle KrAZ-250 can run steadily at a rotation speed of 550 rpm. In the second gear with minimum engine rotation speed, the delivery of a pump wit

32、h a cylinder of 90 mm diameter can be reduced down to 1.0 m3/h.Unlike the SIN32 pump, the delivery of the NPTs-32 pump can be controlled during the technological operation and reducing or raising the delivery can change the pump output. Removal and installation of two valves do not take too long.Let us see how the uniformity of pump delivery will change upon removal of the valves.It is well known that the instantaneous output of a single-cylinder single-acting pump isq = Frsin = 0.5FSsin,where r is the radius of the crank and is the cranks