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PDC切削齿破岩受力的数值模拟研究

收稿日期:2005-11-01;修回日期:2006-05-26

基金项目:本文系国家/十五0攻关项目/复杂油藏配套钻井技术及关健装备研究0(编号:2003BA613A-11)的部分成果。

作者简介:马清明(1966-),现为中国石油大学(华东)博士研究生,主要从事石油工具的研究和开发工作。联系地址:(257017)山东省东

营市北一路236号胜利石油管理局钻井工艺研究院,电话:0546-8771039,E-mail:zjymqm@https://www.wendangku.net/doc/069641401.html,

钻采机械

PDC 切削齿破岩受力的数值模拟研究

马清明1、2

,王瑞和1

(1中国石油大学石油工程学院#华东2胜利石油管理局钻井工艺研究院)

马清明等.PDC 切削齿破岩受力的数值模拟研究.钻采工艺,2006,29(4):78-80

摘要:对PDC 切削齿破岩过程中与岩石之间的相互作用,给出了摩擦接触有限元的分析方法,采用粘-滑摩擦模型模拟接触状态,并用罚函数与拉格朗日组合法进行求解。研究了P DC 切削齿的负前角、切削深度等对PDC 切削齿和岩石受力的影响作用规律。数值计算的结果较真实地反映了PDC 切削齿破岩过程中所受接触压力、有效应力和摩阻应力的分布变化情况,据此给出了实际可用的建议。研究结果为P DC 破岩工具的设计和应用提供了依据。

关键词:钻头;切削齿;岩石;摩擦接触;有限元;围压

中图分类号:TE 8211102 文献标识码:A 文章编号:1006-768X(2006)04-0078-03

PDC 具有很高的硬度和耐磨性,作为高效切削元件被广泛地用于破碎岩石。一般PDC 破岩工具有多个切削齿,工具的受力和工作状态取决于各个切削齿的受力和工作状态,而切削齿的受力是影响其磨损和工作状态的一个关键性因素。通过试验模拟建立PDC 切削齿的宏观受力特性与破岩效果之间的关系

[1]~[4]

,在实际应用时,由于缺乏对PDC

切削齿破岩工作状况更为深入细致地了解,往往没有将这种高效破岩工具的优势充分发挥出来。鉴于此,本文采用摩擦接触有限元法对PDC 切削齿破岩过程中的受力情况进行模拟研究,在完善现有PDC 破岩工具设计和应用基础理论的同时,也试图探索一种能将石油钻井工具的研发引向深入的途径。

一、有限元分析

1.PDC 切削齿与岩石相互作用模型

PDC 切削齿破岩时,所受到的岩石反作用力可分解为正压力F n 、切向力F c 和侧向力F l 三个分力,本次研究假设切削齿的轴线在与岩石切削表面垂直的平面内,因此认为切削齿的侧向力F l 为零。建立PDC 切削齿与岩石互作用模型如图1所示,分析采用复合片直径为13.4mm 的PDC 切削齿。2.摩擦接触有限元分析

PDC 切削齿破岩过程中与岩石相互作用,力学

上可定义为两个物体之间的摩擦接触。接触问题本身是一种受载荷、材料、边界条件等诸多因素影响、

高度的状态非线性行为,分析难度较大,如果在接触问题中再引入摩擦的因素,则使问题的分析变得更加困难,采用有限元等数值法求解摩擦接触问题是一种有效且可行的方法。

图1 PDC 切削齿与岩石互作用模型

根据变分原理,由两个相互接触物体所组成的系统,在和接触边界有关的单元上,外力虚功

为[5]~[8]:

R V =

{P e v }T

{R u e }d 8+

′

{P e s }T {R u e

}d ′

+{R e i }T

{R u e

}

(1)

式中:{P e

v })单元体力向量;{P e

s })单元面力向量;{R e

i })单元接触边界上的接触力向量;{R u e

})单元内虚位移向量;{R u e })单元节点虚位移向量;

′e

)单元上的作用面力的边界;8e )单元区域;

R V )外力虚功。

78# 钻采工艺DRILLING &PRODUCTION T ECH NOLOGY 2006年7月 July 2006

其内力虚功为:

R U=Q8e{R e}T{R E e}d8(2)式中:{R e})单元内的应力向量,是坐标函数; {R E e})单元内虚应变向量;R U)内力虚功。

由有限元理论可知:

{R u e}=[N e]{R u e}(3)

{R E e}=[B e]{R u e}(4)

{R e}=[B e][D]{u e}(5)式中:[N e])单元形函数矩阵;[B e])单元应变矩阵;[D])弹性矩阵;{u e})单元节点位移。

由虚功原理可知,当系统处于平衡状态时,其外力虚功和内力虚功相等,即

R V=R U(6)

系统的总势能为:

F=R U-R V(7)

利用最小势能原理,在所有可能的位移中,真实

位移使总势能取得最小值,由

9{u e}={0}推出:

[k e]{u e}={P e}+{R e}(8)式中:[k e])单元刚度矩阵;{P e})单元载荷向量; {R e})单元接触力向量。

考虑其它和接触边界无关的单元进行组集:

[k]{u}={P}+{R}(9)式中:[k])整体刚度矩阵;{P})整体载荷向量; {R})整体接触力向量;{u})整体刚性位移。

从式(7)和式(8)的比较中不难确定单元刚度矩阵和单元载荷向量的表达式。如分别对两个物体单独写出其刚度方程式,则有

[k1]{u1}={P1}+{R1}

[k2]{u2}={P2}+{R2}(10)

式中:下标1,2分别代表物体1,2。

由于接触力{R1}、{R2}未知,因此在式(10)中,未知数个数多于方程数,无法直接求解,必须补充对应接触点对的接触连接条件,为此,应首先假定各接触点对的接触状态,并代以相应的接触定解条件,再求解式(10)。从而可以求得:

u*1=[P*1][K*1]-1

u*2=[P*2][K*2]-1

(11)式中:[K*i])把补充方程代入后形成的修改后的刚度矩阵(i=1,2);[P*i])把补充方程代入后形成的修改后的载荷向量,其中也包含了接触力。

根据求出的节点位移,再用求节点力的方法求出接触点对上的接触力向量,然后,根据接触点对上的位移和接触力向量,依次按接触判定条件判断各点对接触状态是否和假定接触状态相符,如不相符则重新修改接触状态,重新把接触定解条件代入式(10),经反复迭代直到该次计算前后接触状态完全吻合为止[5]~[8]。

3.接触边界的处理

为了满足接触相容性,在垂直于目标面的趋于减小穿透深度的方向施加一个适当的力[9]:

f n=min(0,K n g+K i+1)(12)

式中:K n)法向接触刚度;g)穿透深度的间隙值; K i+1)第i步迭代时的拉格朗日乘子。

K i+1=

K i+A K n g|g|\E

K i|g|

(13)式中:E)相容性容差;A)内部的计算因子,A<1。

由于接触节点相遇并沿目标面移动而引起摩擦将产生切向力,一般有三种情况:

f s=

0无摩擦

K t u e s

f s滑移

(14)式中:K t)粘滞刚度;f s=-L f n)库仑摩擦模型的粘滞极限值;M)静、动态摩擦因子;u e s)弹性切向变形;L)摩擦系数。

单元载荷矢量(New ton-Rapson失衡力)为:

{f ne l}=f n{N n}+f s{N s}(15)式中:{N n}和{N s})分别为法向和切向的插值函数。

接触单元的切向刚度矩阵为:

[K l]=

K n{N n}{N n}T+K t{N s}{N s}T粘滞接触

K n{N n}{N n}T滑移或无摩擦接触

0无接触

(16)

二、数值模拟结果及分析

模拟分析用切削齿和岩石的力学参数,如表1。

表1切削齿和岩石的力学参数

名称弹性模量(GPa)泊松比密度(g/cm3)

切削齿2060.267.85

岩石250.21 2.11

1.切削齿受力分析

设定PDC切削齿所受正压力F n为2.8kN,切向力F c为2.5kN,切削齿与岩石之间的摩擦系数为0.3,切削深度为5.0mm,负前角为15b,岩石所受围压为20MPa。计算结果显示,PDC切削齿与

第29卷第4期Vol.29No.4

钻采工艺DRILLING&PRODUCT ION T ECHNOLOGY

岩石之间的接触压力最大值5.32M Pa出现在距齿底2.7mm处。PDC切削齿最大有效应力为1.6 M Pa,距离齿底部2~2.5mm,接触齿上部的应力值较小,约为0.2MPa左右。结果说明,由于PDC切削齿破岩过程中所受载荷呈非均匀分布,有可能因局部磨损剧烈而加速切削齿的整体报废,因此强化PDC切削齿表面耐磨层的材质,局部增大切削齿受力较大部位耐磨层的厚度,是延长PDC切削元件使用寿命的一个有效途径。

2.负前角对切削齿受力的影响

表2反映了负前角的变化对PDC切削齿受力的影响规律(正压力等参数的设定与上述分析相同)。从表2中可以看出,切削齿接触压力和摩阻应力随着负前角的增大而逐渐减小,其中原因是在切削深度一定的情况下,切削齿与岩石的接触面积随着负前角的增大而增大,致使接触压力和摩阻应力减小。表3中的计算结果还表明,随着负前角的增大,PDC切削齿所受的有效应力逐渐增大,而岩石所受的有效应力则逐渐减小,这说明减小负前角,有利于延长PDC切削齿的寿命,提高破岩效率,室内实验结果也证实了这种规律[10]。

表2负前角对切削齿受力的影响

负前角(b)齿接触压力

(M Pa)

齿摩阻应力

(M Pa)

齿有效应力

(M P a)

岩石有效

应力(M Pa)

15 5.32 1.6 1.618.6

20 4.83 1.44 2.0816.8

25 4.44 1.41315.1

30 4.17 1.25 3.8813.5

35 3.71 1.11 4.7812.6

3.切削深度对切削齿受力的影响

表3中的切削深度对切削齿受力影响的计算结果表明(正压力等参数的设定与上述分析相同),随着切削深度的增大,PDC切削齿接触压力、摩阻应力和有效应力逐渐减小,岩石所受的有效应力则逐渐增大,这是因为切削齿承载面积随着切削深度的增大而增大,改善了切削齿的受力状态,因此较大的切削深度对提高PDC切削齿的破岩效率、延长切削齿的寿命是有利的。但是由于实际地层的非均质性和破岩工具工作状况的波动会对PDC切削齿造成冲击,如果切削深度过大,则可能由于承受过大的冲击载荷,损坏PDC切削齿,因此实际应用中还是应采取必要的措施控制PDC切削齿的切削深度。

表3切削深度对切削齿受力的影响

切削深度

(mm)

齿接触压力

(M Pa)

齿摩阻应力

(M Pa)

齿有效应力

(M Pa)

岩石有效

应力(M Pa)

2 6.6

3 1.99 4.2515.8

4 5.8 1.74 3.0616.6

7 5.12 1.6 1.618.6

100.710.12 1.2918.9

12.90.320.10.6218.8

三、结论

(1)PDC切削齿破岩时最大接触压力和最大有效应力出现在距离齿底部一定距离处。

(2)减小PDC切削齿的负前角和增大切削深度有利于改善PDC切削齿的受力状态,延长破岩工具的寿命,提高破岩效率。

(3)本文研究所用方法,也可用于分析其他石油钻井工具的摩擦接触问题。

参考文献

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术,2003,31(3):4-6.

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关系的试验研究[J].大庆石油学院学报,1997,21

(2):23-25.

[3]夏宏南,王克雄,翟应虎,等.围压条件下PDC钻头不

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沙交通学院学报,1999,15(2):13-16.

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47,58.

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#钻采工艺

DRILLING&PRODUCTION T ECH NOLOGY 2006年7月July2006

K ey words:completion method,sand producti on,mathematical model,empirical formula,produ ctivity pred iction

Z UOXing,born in1981,is studying for h i s Master.s degree in Southwest Petroleum University,is engaged in the research on oil/gas well.Ad d:Master Grade200,Southw est Petroleum In stitu te, Ch engd u610500,Sichuan,China Tel:135********E-mail: zu oxing921@https://www.wendangku.net/doc/069641401.html,

MO DELING ST RATE GY ST UDY IN O ILFIELD EARLY DEVEL-OPMENT PE RIO D

LI Fang ming1,ZHAO Gu oliang1,JIANG Bi w u1,ZHAO Dongmei2 and WANG Ru ifeng1(1.Research Institute of Petroleum Exploration and Development;2.Petroleum Industry Press),DPT29(4),2006:67-69 Abstract:Reservoir modeling is one of the most fundamental and cru cial techniqu es for field development.But its reli abi lity is often cha-l lenged in oilfield early develop m ent peri od w ith very few w ells.T hi s pa-per has p ut forward a modeling strategy on th e basis of geol ogical con-cep t,stoch astic simu lation theories,and variou s kinds of d ata to b uild a reasonable reservoir mod el.Taking Sudan FL oilfield as example,this in-tegrated seismic inversi on and stochastic modeling method w ere ad opted to build facies model and facies-controlled p etrophysical mod el by usi ng sei smic impedance data,thus the indeterm in atenes s of inter-well reser-voir predi ction could be greatly d ecreased.

K ey wo rds:mod eling strategy,stochastic modeling,stochastic seis-mic inversi on,facies-controlled modeling

LI Fa ngming(doctor,prof e ssor),b orn in1963,i s engaged in the research on oi lfield develpment i n Petroleum E xploration and Develop-ment Research Institute.Add:20Xueyu an Road,Haid ian Distri ct, Bei jing100083,China T el:(010)62093184E-mail:lfm@ p https://www.wendangku.net/doc/069641401.html,

APPLICATIO N PRO SPE CTS O F ALC OH OL-BASE ACID AND ALCO HO L-BASE FRACT URING FLUI D IN XUJ IAH E GRO UP O F S OUTHE RN SI CHUAN AREA

LI Xu eka ng1,2,S IMA Liq iang1,SONG Huaq ing2,WU Guopi ng2, ZHONG Qi ong2and ZHENG Yuming2(1.Southwest Petroleum Univer-sity; 2.South ern Sich u an Gas Field,Petroch i na Southwest Oil&Gas Field Company),DPT29(4),2006:70-72

Abstract:Sand stone reservoir in Xujiahe group of Southern Sichuan area has th ese characters as follow:p erm eability is low,the d amage of water sen sitivity and w ater blocking is midd le or h igh,pressure coeff-i ci ent is low,fluid displacement i s diffi cu lt after sand fracturing or acidiz-ing treatment,and su cces sful rate of reservoir reconstruction i s l ow.This article comp ares and analyses the ad vantages and disadvantages of water -b ase fracturing fluid,li quid CO2fracturing flu id,foam fracturi ng flui d, alcohol-base fracturin g fluid and alcohol-base aci d.Based on the com-paring and analysis,it i s though t that alcohol-base fractu ring flu id is suitable to th e tight sandstone reservoir reconstruction of Xujiahe group of Southern Sichuan area,and have good ap plication p rosp ects.Alcohol-b ase acid can be u sed as the assistant method s and sup plementary means of sand fracturing.Writers suggest that the related u nits should engage in the methanol and alcohol fracturing flu id research and on-site test.

K ey wo rds:Southern Sichuan area,Xujiahe group,l ow porosi ty and l ow permeability reservoir,sand fracturing,acidification,alcohol-base acid

LI Xuekang(engin eer),grad uated from Geologic Department of Northw est University in1991,now h e i s stud ying for his Master.s de-gree in Southw est Petroleum Institute.Add:Southern S i ch u an Gas Field,Petrochina Southw est Oil&Gas Field Company,Luz hou646001, Sichuan,China Tel:135********E-mail:lxklxk@https://www.wendangku.net/doc/069641401.html, ME CHANIC AL DESIG N O F ST ABI LIZED PLATFORM UNIT IN T HE RO TARY STEE RING DRIL LING T OO L

YAN W enhui,PENG Yong,ZHANG Shaohuai and LI Jun qiang (College of Mechani cal Engineering,Xi.an Shiyou University),DPT29 (4),2006:73-75

Abstract:Mech anical design of stabilized p latform unit is one of the key techniques in the rotary steering drilling tool.Stabilized platform is controlling unit of th e rotary steering d rilling tool,its functi on is to en-sure that it is not to be influenced by rotati on of su ck er rod string w hen d rilling;to match regu lation and control of instruction sets for steeri ng tool.s triangle face of the rotary steering drilling system lively w hile drilling in order to realize its steering fun ction;and to take over charge of transmi ssion over radio for measurement and control information between itself and MWD.The p ap er introd uced the work ing principle of stabilized platform unit in the rotary steering drilling tool;show ed the design me-chanical structure draw ing of stabilized p latform,and pointed out several characters of the mech anical design of stabilized platform unit,su ch as: carried out the whole s cheme.s selective analysis of stabilized platform.s sup porting to determine a upper hanging project that the w hole stabilized platform.s w eight hangs on the main p ed estal of the platform stab iliza-ti on;d id comparison and analysis for bearing selection to d etermine a d e-sign project of the rolling bearing.s structure and d esigned a bearing pro-tector in order to improve the bearing.s service li fe;analyzed the driving moment and dragging moment w hen stabilizati on platform.s spind le con-trols th e bearing.s rotation,and presented a solution to the balance of sup ply and demand for required torque;analyzed th e factors w hich influ-ence the w hole rigid ity of the stabilized p latform.s spind le,presented method s w hich can improve the whole rigidity of the stabilization plat-form;carried out the analysi s about the static and dynamic b alance of th e stabilized platform.s rotating spindle;stated the reas on w hy to select an-ti magnetic material and adj ustment m ethods of axi al cumu lative mach in-ing toleran ce and setting up errors and so on.T he implementing of th ese meas ures en sure the reali zation of th e whole stabilized pl atform function in machining design.

Key wo rds:rotary steering drilling tool,stabilized platform,me-chanical system,design

YAN W enhui(master,vice prof e ssor),born in1965,tutor of masters,mainly is engaged in teaching and scientific research.The re-search direction:the design of oi l machinery and monitoring and fault d-i agnosis of eq uipment.Add:Xi.an Shiyou U niversity,Xi.an 710065,Shanxi,China T el:029-********E-yw h369@ xsyu.ed https://www.wendangku.net/doc/069641401.html,

THE ORETIC AL CALCULATIO N OF B ULG ING FO RCE ON E X-PANSIO N CASING

G ONG Long xiang1,FU Jianhong1,LIN Yuan h u a1,GAN Sh eng-ping2and LI Zhiping3(1.State Key Laboratory of Oi l an d Gas Reservoir Geology and Exp loitation,SWPI;2.West Sichuan Drilling Co.,S i chu an Petroleum Admini stration;3.Southern Sichuan Co.,Sichuan Kehong Natural Gas Co.),DPT29(4),2006:76-77

Abstra ct:According to the elastic-plastic theory,the calcu lation method of tangentialstress,radial stress of exp ansi on casing both in elas-ti c deformati on area and in plastic deformation area is deduced and th e minimum critical load betw een expan sion core and casing was deter-mined.The paper analyzed the force of expansi on core,consi dered the in-fluences of friction coeffi cient and expansi on cone an gle on critical load, the calculati on method of b ulging force of expan sion casi ng is given.Th e influence of related parameters on ten sion of exp an si on core w ere dis-cus sed.Th e theoreti cal calculati on resu lts of tension of expansion core w ere compared w ith experimental data,and it is show n that the accuracy of the theoretical cal cu lation meets the need s of engineeri ng applicati on1 Key words:exp ansi on casing,b ulging force,expan sion core,critical load

G ONG Lo ng xiang,born in1982,grad uated from Wuhan University of T echnol ogy in2004,is stu dying for his Master.s degree in SWPI. Add:State Key Laboratory of Oil and Gas Reservoir Geology and Ex-pl oitati on,Southw est Petroleum Institute,Xindu Di strict,Chengdu 610500,Sichuan,China Tel:(028)83033964E-m ail: lone1981918@https://www.wendangku.net/doc/069641401.html,

NUMERICAL S IMUL AT ION S TUDY ON FORCE OF PDC CUT-TE RS CUTTING ROC K

MA Q ingming1,2and WANG Ruihe1(1.College of Petroleum Eng-i neering,China Universi ty of Petroleum(East China);2.Drilling Tech-nology Research Institute of Shengli Oilfield),DPT29(4),2006:78-80

Abstra ct:Based on the mutual effect betw een PDC cutter and rock during th e rock-breaking,th e analytical approach of rubb ing contact f-i nite element is given.Vis cous-sliding fri ction mod el is adop ted to simu-late the contact situ ation,penalty function and Lagrange combi nation method are utilized for sol utions,the influence law of interfacial friction

Vol.29No.4July2006DR ILL IN G&PRODU CT ION T ECHNOL OGY

coefficient und er confining pressu re,together w ith the negative rake and

cutting depth of PDC cutters,on the forces of PDC cutters and rock is studied.Nu m eri cal calcu lation results precisely show the vari ation of con-tact pressure,effective stress and fricti onal resistance stress of PDC cu t-ters d uring cutting rock.In terms of th e above,the practical and useable advice is put forw ard.Research results offer foundati ons for the desi gn and ap plication of PDC rock-break ing tools.

K ey wo rds:bit,cutters,rock,ru bbing contact,finite element,con-fining pres sure

MA Qing ming,born in1966,now is stud ying for his PH.D degree in Ch i na University of Petroleu m(East China),and is engaged in the re-search and development of petroleum tool s.Add:China University of Petroleum(East China),Dongying257061,Shand ong,China Tel:0546-8771039E-mai l:zjymqm@https://www.wendangku.net/doc/069641401.html,

DEVELO PME NT O F A NEW CONTINUOUS CARBO N FIBER B USYW O RK UNIT

PENG Yo ng1,YAN Wenhu i1,ZHI Ligu ang1,WU Heng1,GU Xuelin2and CHANG Deyou2(1.M echanical Engineerin g School,Xi.an Shiyou Universi ty; 2.General Engineering Mach in ery of Shengli Petroleum Administration),DPT29(4),2006:81-82

Abstract:A new continu ous carb on fiber bu syw ork unit is deve-l oped,w hich can separately drives the sucker rod lifting(setting dow n) and the s uck er rod coiling.T he b usywork units controlled by the hy-draulic transmis sion and control technology and the bu sywork process is monitored by intelligent control technology,inclu ding the digiti zing m ea-sure of busywork parameters,automatic controlling the location for rod centralizer,automatic alerting for op eration security,etc.According to the situation that the sucker rod is h ard to b e concentri c w ith th e central of the well,th e lifting(setting down)assembly and coiling unit are de-signed to be mobile.Th e chief character is that i t has strong ability for lifting(setting down)the road,the mechani cal conditi ons of the sucker rod can be greatly improved,the torq ue of coiling load i s low,the bu sy-w ork unit has high automatization,quick working rate,strong adapti ng ability to th e w ell site and has few d amageable workpieces and can be maintained easy,be used for both transp orti ng the sucker rod s and work-ing,it can redu ces the equ ipment investment and gets long-lasti ng working ti m e.

K ey wo rds:continuous carbon fiber sucker rod,bu syw ork unit,de-sign

PENG Yo ng(pr o f essor),born in1961,graduated from Petroleum M echanical Engineering Department of Daq ing Petroleum Institute in 1988,is engaged in teaching,scientific research and management of me-chanical system cond ition monitoring and fai lure diagnosi s and modern de-sign m ethods in Xi.an Shiyou University.Ad d:Mechani cal Eng-i neering School,Xi.an Shiyou Universi ty,Xi.an710065,Shanxi,China Tel:(029)88382601E-mai l:ypeng@https://www.wendangku.net/doc/069641401.html,

S TUDY ON S OFTW ARE FO R LO AD ANALYSIS AND OPTI-MIZATIO N DES IGN O F FRACT URE ACIDIZING TUBE

DING Peng,YAN Xiangzhen and YANG Xiujuan(China University of Petroleum(East China)),DPT29(4),2006:83-85

Abstract:Based on the actual requirements of d rilling technology p rogress and current oil and gas exploration and d evelopment,the nu mber of deep w ell,ultra-deep w ell increases con tinuously.In order to meet these requirements,on the basis of fracture acid izing tube injection strength design softw are for normal straight w ell,the characteri stics of fracture acidizing tube injection load for b oth deep w ell and ultra-deep well are studied,and d esign method of the conventi onal fracture acidizing tube and the triaxial stress is consid ered.Th e injection strength desi gn softw are of acid fracturing tub e is develop ed.T he software possesses mu-l tifunction in acid fracturing tu be opti m iz ation design for normal w ell,deep well and sep arated layer acid fractu ring and its operation of input-ou tput interface is simple,it s hould be widely u sed on site.

K ey wo rds:fracturing,acidizing,force analysis,deep w ell,design

DING Peng,b orn in1980,now is studying for his PH.D degree in Ch in a University of Petroleum(East China),and is engaged in the re-search on oilfield equ ipment management.Add:211engineering of-fice,China University of Petroleum(East China),Dongying257061, Shandong,China T el:0546-8391820E-mail:djg203@ si https://www.wendangku.net/doc/069641401.html,

PRACTICE O F ACO USTIC E MIS SIO N INSPE CTIO N IN A S IN-G LE RAM-BO P

ZHU Xiang ju n(Tech n ology T est Center Of Sichuan Petroleum Ad-ministration),DPT29(4),2006:86-87

Abstra ct:The paper briefly introduces the w orking prin cip le and technical features of acoustic emission(AE)technol ogy.On the basis of the structural characteristi cs of a single ram BOP,a scheme of plan ar lo-cation of AE test is proposed.Th e p aper describes th e p reparation work before a AE test.With u sing two time load ing,contrasting the d ata co-l lected in the tw o tests,combining the prin ci ple of Kaiser effect,and comprehensively analyzing noise sources in the tests,the effective signals is picked u p from the d ata acquired at the pressure hold ing stage,and th e nature of defect is determined on the b asi s of the effecti ve signals.Fina-l ly,it gives the results of test and puts forw ard the problems wh i ch ur-gently need to be solved i n present and the directi on of w ork.

Key words:acoustic emi ssion test,BOP,planar location

ZHU Xia ngju n,born in1978,grad uated from China University of Petroleum(East Ch in a)in2000,i s engaged in the AE test in Tech n olo-gy T esting Center of Sichuan Petroleum Admini strati on.Add:Tech-nology Test Center Of S i chu an Petroleum Ad ministration,Guanghan 618300,S i chu an,China T el:(0838)-5151369E-mail:zx-j fire@https://www.wendangku.net/doc/069641401.html,

STUDY AND APPLICATIO N O F NITROG EN FOAM PROFILE CO NT RO L IN HEAVY OIL THE RMAL PRODUCTIO N

LU Gu angzho ng1and ZHANG Jiangqi ao2(1.Geological Scientific Research In stitu te,Shengli Oilfield,Sinopec,;2.College of Mechanical an d Electroni c Engineering,China Universi ty of Petroleum(East Ch-i na),DPT29(4),2006:88-90

Abstra ct:Nitrogen foam thermal flooding is a new method for en-hanced oil recovery of heavy oil.On th e basis of the data of foam i ng a-gents and crud e oil w hich are sup plied in field,the mechanis m of nitrogen foam profile control used for enhanced oil recovery i n heavy oi l thermal producti on i s studied,and op timization and evaluation of foaming agents are carried ou t by laboratory test.T he results of dis placement experiment indicated that ulti m ate oi l di splacement efficiency is high up81.44%, an d i s increased by34.3%than water fl ood ing,the resid ual oil satu ra-ti on i s11.14%.At same ti me,the field desi gn and app lication effect of nitrogen foam profile control are analysed.The field application show s that nitrogen foam can red uce greatly w ater-cut,and enhan ce recovery efficiency.

Key words:nitrogen foam,profile con trol,heavy oil,recovery eff-i ciency,mechani sm

LU G ua ngzhong(a ssocia te p ro f essor),born in1974,graduated from College of Petroleu m Engineering in the China University of Petroleum and acquired Ph.D in2003,i s engaged i n research on reser-voir engineering and s oftw are development.Add:Geol ogical Scien-ti fic Research Institute,Shengli Oilfield,Sinopec,Dongying257015, Shand ong,China T el:0546-8715093E-mail:d zylgz@slof. com

EXPERIMENTAL AND THE ORETIC AL S TUDY O N RO CK STRESS-SENSITI VIT IES IN L OW PERMEABILITY S ANDSTO NE LI Min1,QIAO Guoan2and CHEN Hao2(1.State Key Lab of Oil an d Gas Reservoir Geology and Exploitation,South west Petroleum Inst-i tute;2.Zhongyuan Oilfield Exploration and Devel opment Research Inst-i tute),DPT29(4),2006:91-93

Abstra ct:Terzaghi effective stress equals the outer stress(the con-fining pressure)of rock m in us its inner pore p ressure.The value of effec-ti ve stress by in creasing th e outer pressure i s th e same as that of decreas-ing th e inner p ore pressure of th e same value accord ing to his theory. Th erefore,measu rem ent of permeability and porosity stres s-sensitivity can be done th rough increasing th e ou ter stres s in laboratory instead of decreasing its inner pore pres sure.The results from the experi m ent s how that the l ow permeab ility sandstone reservoirs have strong permeabi lity stress-sensiti vity an d low porosity stress-sen sitivi ty.Because the effec-ti ve stress is eq ual to the net confining pressure,it red uces the p ermeabil-i ty significantly as reservoir pressure d ecreases.The paper introduces th e double effective stres s th eory.T he effective stress is not equal to the net confining pressure in ligh t of the theory.It equals th e outer stress sub-

#DR ILL IN G&PRODU CT ION T ECHNO LOG Y Vol.29No.4July2006