Research on the Method of Identifying the Indicator Diagram of the Sucker Rod Pumping Unit

Transcription

1 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: eseach on the Method of Identifying the Indicato Diagam of the Sucke od Pumping Unit Cun Lu, enze Luo, Peng Jiang College of Mechanical and Electical Engineeing, Southwest Petoleum, Chengdu Sichuan, 60500, China College of Eath Science and Technology, Southwest Petoleum, Chengdu Sichuan, 60500, China Abstact In the poduction pocess of oil well,using indicato diagam can accuately diagnose out of the woking conditions of sucke od pump in the undegound seveal kilometes, extacting the featue values of indicato diagams accuately is the key link in the pocess of identification of indicato diagams. This pape fistly uses Gibbs wave equation to tansfom the gound indicato diagam into undegound pump indicato diagams, then combined with geometic featues values extaction and gid featue values extaction to extact the featue values of indicato diagams, finally, using Bp netwok and Euclidean distance classification to ecognize indicato diagams. the esult shows that compaed with the single geometic featue extaction and the gid featue extaction,fo the simila indicato diagams,the has highe coect ecognition ate and the effect is moe stable, it povides an effective way to ealize the fault diagnosis of sucke od pumping well and the constuction of digital oil field. Keywods Indicato diagam, identification, featue extaction.. Intoduction In the field of oil poduction in China, the sucke od pump is the most widely used, which accounts fo moe than 90% of the total numbe of atificial lift-wells []. Because the oil-well pump is located in thousands of metes deep undegound, and affected by the wa gas and wate, it is moe pone to failue and vey difficult to obtain its woking condition diectly to wok in this vey complex situations, the cuent common to get its woking condition is though the analysis of indicato diagam of pumping unit which is dawn with the displacement of sucke od as abscissa and its load as odinate, as shown in Figue. At pesent, most oil fields still adopt the way of atificial peiodic inspection to check its woking condition, Fom the fault occuence to find fault, and then identify the fault, this pocess extends the stop time, which educes the pumping efficiency. With the pogess of science and technology, this way of fault diagnosis seiously hindes the development of oil fields to digital and intelligent, How to use compute to ecognize automatically instead of atificial ecognition is one of the main eseach contents of petoleum engineeing scholas at home and aboad at pesent. In the identification pocess of indicato diagams, whethe the extacted featue values can accuately epesent the main featues of the powe diagam, plays a decisive ole fo the accuate identification of indicato diagams. At pesent, fo the extacting of the featue values of indicato diagams, geometical extacting and gid featue extacting ae widely used. Such as the liteatue [3], It uses all the data points of the indicato diagam as featue values, and compaes them with benchmak, this 54

2 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: contains includes compehensive infomation. Howeve, due to evey indicato diagam contains hundeds of data points, the calculation will be vey lage to use this. In liteatue [4], geometical featue values, such as aea, peimete, Maximum load, Minimum load, ae used as the featue values of indicato diagams, although this can educe the amount of calculation, but it can only be used to diagnose indicato diagams that have obvious featues. In liteatue [5], the indicato diagam is is boken down into a numbe of gids that have the same shape and size, and assign value to evey gid based on its location, then calculate its gay aveage, gay vaiance, gay deflection, gay keenness, gay enegy and gay entopy, these gay values ae used as the featues of the indicato diagam, but it also can only be used to diagnose indicato diagams that have obvious featues. To this end, this pape pesents the combination of the geometical extacting and gid featue extacting, it can not only educe the dimension of featue vectos, but also accuately eflect the details of the indicato diagam.. The establishment of wave equation The undegound pump indicato diagam can diectly eflect the woking condition of the pump, but it is difficult to obtain diectly due to the pump is located in the undegound thousands of metes, theefoe, it is need to establish the sucke od wave equation. In 966, the Ameican shell company of Gibbs and S.G fistly established the sucke od wave equation, it is the famous Gibbs wave equation [6], the equation is as follows: u x t u x t a c ) (, ) (, t x t () In (), - the displacement of the coss section of x metes depth of sucke od at the time of t, a- the popagation velocity of stess on the sucke od sting, c - damping coefficient. The Fouie seies epesentation of the uppe and lowe bounday conditions and the initial conditions ae as follows: f ( x x t t L 0 D( v0 0 U( 0 0 t 0 0 n n n n ( n cosnt nsin n ( vn cosnt nsin n () In (), f ( - the load of the plunge at displacement x and at time t, D( - the displacement of suspension point at time t, U( - the displacement of polish od at time t, n, n, v n, n - Fouie coefficients. By means of sepaation of vaiables and Fouie tansfoms can calculate u ( : 0 EA v0 x N n ( On( x)cos nwt pn( x)sin nw (3) Accoding to Hooke's law, can obtain f ( : 0 f ( EA EA x N n ( O'( x)cos nwt P'( x)sin nw (4) 55

3 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: In (4), On( x) ( knchnx nshnx)sin nx ( unchnx vnshnx) cos nx (5) Pn( x) ( knchnx nchnx)cos nx ( nchnx vnshnx) sinnx (6) n n O'( x) [ shnx ( nn vnn) chnx]sin nx [ chnx EA EA (7) ( vnn nn) shnx]cos nx n n P'( x) [ chnx ( nn vnn) shnx]cos nx [ shnx EA EA (8) ( vnn nn) chnx]sin nx k n nn nn EA( n n ) (9) nn nn n (0) EA( n n ) Accoding to the solution of the wave equation and its bounday conditions, the gound indicato diagam can be conveted to the undegound pump indicato diagam. 3. Featue value extaction As the indicato diagam changes vaied, the diagam is diffeent geatly in spite of the same faults, in ode to make the extacted chaacteistic value can epesent the tue shape of the figue, and we take geometic and gid to extact the featue value. 3. Featue extaction of geometic The featue extaction of the geometic is to obtain the chaacteistic value diectly o do some simple geometic opeations to obtain, this is easy to opeate and the calculation amount is small. Hee, we extact the following chaacteistic values. Table geometic chaacteistic value Standing point of upstoke (A) End point of stoke defomation (B) End point of upstoke (C) End point of down stoke defomation (D) Left uppe pat aea (A) ight uppe pat aea (A) Left lowe pat aea (A3) ight lowe pat aea (A4) Maximum load (Fmax) Minimum load (Fmin) Centoid (G) 56

4 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: Featue extaction of gid Fig. geomety chaacteistic values Gid of featue extaction is to divide the indicato diagam into some gids[7], as shown in the figue below, assign fo the gids which ae cossed by the indicato diagam s outline, take these gids as the benchmak, if the gids ae outside the indicato diagam s outline, theis values minus each away fom a gid, if the gids ae inside the indicato diagam s outline, theis values plus each away fom a gid, then calculate its gay aveage, gay vaiance, gay deflection, gay keenness, gay enegy and gay entopy, and take them as the featue values. Fig. gid chaacteistic values Specific chaacteistic values ae calculated as follows: Gay aveage: f g p( () Gay vaiance: f ( g) p( () Gay deflection: f 3 S 3 ( g) p( 3 (3) Gay keenness: f 4 P 4 ( g) p( 4 (4) Gay enegy: f E p( (5) Gay entopy: 5 f T [ p( ] lg[ p( ] (6) 6 57

5 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: BP neual netwok identification Atificial neual netwok is established accoding to the neual netwok, and it is a mathematical model of infomation pocessing which is simila to the stuctue of the synaptic connection of the bain. The most epesentative is the BP neual netwok model developed in ecent yeas, it is though the eo back popagation to change the inteconnected elationship between nodes to make minimum the eo sum of squaes which is also called the steepest descent, because of its simple, easy opeation, small amount of calculation, making it become the most matue taining cuently. The fault diagnosis is ealized by thee laye netwok, and the input laye of the netwok is 7 chaacteistic values, Implicit laye selects the function of Sigmoid fo intenal leaning and pocessing, The numbe of output nodes is set to 4. In the expeiment, we selected 500 figues of a field map data as the taining data, the taining esults as shown in figue 3. Fig. 3 taining esults Afte the netwok taining, select some data to test, and compae with the geometic featue extaction and the gid value, the esults ae shown in table. Table Diagnostic esults Method Output esult Diagnostic esults Coect esult geometic nomal nomal gid nomal nomal Geometic nomal nomal nomal Touch the pump gid nomal Touch the pump Touch the pump Touch the pump geometic gid Gas effect geometic gid Gas effect Gas effect Gas effect Gas effect

6 Intenational Coe Jounal of Engineeing Vol. No.3 05 ISSN: As can be seen fom the table that the impoved featue extaction is moe accuate than the geometic and the gid, at the same time, the output of the impoved featue extaction is moe close to the ideal output. 5. Concluding emaks This pape poposes the featue extaction of the combination of geometic and gid, the pactical tests show that it can educes the dimension of featue vectos, and impoves the accuacy of the identification of the indicato diagam. Using compute technology to apply it to oil field poduction can ealize the eal-time monitoing and eal-time diagnosis of the oil well poduction condition. efeence [] Li Jingyuan, Chen Guochun, Li Zifeng. Filteing Technology in the Diagnosis of Sucke od Pump Pumping System [J]. Acta Petolei Sinica, 00, 3(): [] Li Zhaomin, Lin iyi. The od Pumping System Efficiency Analysis and Optimal Design of Swabbing Paamete [J]. Acta Petolei Sinica, 005, 6(5):0-06. [3] Gao Yonglinag, Tan Chaodong, Zhao Haitao. The eseach and Application of Neual Netwok Identification Method of Pumping Well Dynamomete [J]. Petochemical Engineeing, 008, (8):5-53. [4] Liang Hua, Li Mingchuan. Accuate extaction of valve opening and closing points based on the physical meaning of suface dynamomete cad [J]. Petoleum Exploation and Development, 0, 38():09-5. [5] Zeng Jing, Li Mingchuan. Optimization of Diagnosis Based on Neual Netwok [J]. Contol Engineeing of China, 009, 6():-3. [6] S.G.Gibbs,A. B.Neely. Compute Diagnosis of Down-hole Conditions in Sucke od Pumping Wells [J].Jounal of petoleum technology, 966():9-98. [7] H Chang,Y Zhang, L Chen.An Applied Themodynamic Method fo Coection of TDC in the Indicato Diagam and Its Expeimenta Confimation [J]. Appied Thema Engineeing, 004, 5 (5):