小位移深造斜点定向井施工技术

小位移深造斜点定向井施工技术y

董云安 陈小元 汪先迎 许尔丹 袁建平 蒋 燕

(江苏石油勘探局钻井处,江苏江都 225261)

摘要 小位移深造斜点定向井技术,有利于减少定向井扭方位及更换钻具组合的次数,能有效降低定向井的成本。主要介绍了小位移深造斜点定向井的剖面设计、定向初始方位角的确定、井眼轨迹控制及安全施工技术等。从2001年起,该技术在江苏油田30口定向井中进行应用,取得较好效果,扭方位次数明显减少,全井未扭方位率达95%,为调整轨迹而更换钻具组合的次数也明显降低,钻井周期也得到一定程度的缩短。

关键词 江苏油田 小位移 深造斜点 剖面 井眼轨迹 成本

江苏油田地质构造小而复杂,且又地处水乡,地面河流纵横,这一条件决定了必须应用多目标、小靶区定向井技术来开发小断块油气藏。虽然定向井工程师在定向前都要利用各区块的方位自然漂移规律来确定一个合适的方位提前角来避免扭方位,但方位漂移受地层、钻具组合、井眼轨迹、钻井参数等诸多因素的影响,要真正掌握一个区块的方位漂移规律难度相当大。大多数情况下,所确定的方位提前角并不合适,从而导致定向井,尤其是位移较大、造斜点较浅、靶区半径小的定向井,为调整井眼轨迹更换钻具次数多,扭方位次数多,一定程度延长了定向井的钻井周期。为解决这一问题,开展了小位移深造斜点定向井钻井技术的研究与应用,要求定地面井位时,在地面条件及防碰绕障允许的情况下,位移尽量要小;剖面设计时,造斜点尽量要深。所谓小位移深造斜点定向井,并无严格的规定,只是根据江苏油田定向井的实际情况,一般认为 靶位移小于200m,造斜点与 靶垂深差小于600m的井,可称为小位移深造斜点定向井。虽然小位移深造斜点定向井存在直井段防斜打直要求高、深部地层定向造斜难度大及造斜段长等施工难点,但直井防斜打快技术的发展及随钻技术在定向井中的应用,为开展小位移深造斜点定向井的施工创造了条件。小位移深造斜点定向井,中靶所需方位范围大,而且斜井段轨迹控制井段短,能有效地解决常规定向井施工中存在的更换钻具组合次数多,扭方位次数多的难题。实践证明,小位移深造斜点定向井钻井技术在降低定向井的扭方位及更换钻具组合次数、缩短钻井周期等方面是行之有效的。据统计,从2001年起,江苏油田共实施小位移深造斜点定向井施工30口,平均井深1987.31m,最深井深为3206m,平均钻井周期为14.9d,平均机械钻速为13.62m/h,全井未扭方位率为95%,为调整井眼轨迹而更换钻具组合的次数也明显减小,平均使用钻头数为6.1只,其技术经济指标高于常规定向井。

1 井身剖面设计技术

小位移深造斜点定向井一般适用于单目标定向井,两靶稳斜角为25 左右的双目标定向井,及两靶稳斜角为0 的双靶挂直定向井。对双靶挂直定向井,一般设计成直增降直或直增稳降直剖面。单靶及两靶稳斜角为25 左右的双目标定向井,一般设计成直增稳剖面。剖面设计无增斜段,以10~15( )/100m的较高造斜率直接定向造斜到稳斜角或最大井斜角,最大井斜角控制在15 ~25 。降斜率采用常规降斜率4~5( )/100m。选择造斜点时,综合考虑防碰绕障、最大井斜角、造斜段长度等因素,尽可能下移造斜点,以减少斜井段的轨迹控制长度。小位移深造斜点定向井,虽然造斜率较高,造斜段较长,但由于直井段长,斜井段短,其井眼剖面与常规造斜率(5( )/100m)的剖面相比,经摩阻分析软件预测,其摩阻值并未明显增加。表1为部分小位移深造斜点定向井剖面设计与摩阻预测值。

第25卷第1期 石 油 钻 采 工 艺 Vol.25No.1 2003年2月 OI L DRI LLI NG&PRODUC TION TEC HNOLOGY Feb. 2003

y作者简介:董云安,1962年生。1981年毕业于江苏石油学校,工程师。电话:0514-*******。

表1 部分小位移深造斜定向井剖面设计与摩阻预测值

井号

斜深/m 方位/( )靶I 靶

位移/m 垂深/m 位移/m 垂深/m KOP /m K 增K 降

/( ) 100m -1

m /( )摩阻预测值/kN 靶区半径

/m Z22-33075.60287.888.42298526001215.488520F1202745.46327.166.90258066.9027002000105

128020Z22-23117.41

278.2151.522702269.46

2940

23001526.3410020S22-12805160.2145.44265021001216.808130X1-11447.7317.690.5412608101213.2

4130M20-121543.7610.568.95144068.95

1540

70010 3.514.354630S11-1

2608

358.3124.87249020001216.327830M20-141539.22316.3116.5814209001014.1

4320W9-8

1944.22

10.92101.841810101.841880123012515.846530S19-192564.85

327.7

129.09

2200

129.09

2500

1570

15

5

23.70

75

30

2 初始造斜方位角的确定

在定向井施工中,为避免扭方位,定向时均要确定一个合适的初始造斜方位角,但受诸多因素的影响,要确定一个合适的初始造斜方位角难度相当大,尤其是对位移较大的井、斜井段轨迹控制井段较长的井。而对小位移深造斜点定向井而言,由于其位移小,造斜点相对较深,中靶所需的方位范围相对较大,斜井段轨迹控制井段相对较短,要确定一个合适的初始造斜方位角相对较为容易。根据施工实践,一般对第1靶点位移小于200m 的定向井,初始造斜方位角的确定要充分考虑直井段井斜及地层方位漂移的影响,具体可按以下方法确定:设初始造斜方位角为 ,直井段底与靶心方位角为 ,直井段所产生的水平位移为S ,靶区半径为R 。参考邻井资料,若斜井段所在地层有较为明显的右漂趋势,则初始造斜方位角确定为 = -12arcsin R

S

;反之,则 = +12arcsin R

S ;若下部井段方位漂移相对较为稳定,则 = '。 ',S '的具体计算见图1

。

图1 ,S 计算简图

图1中A 为设计目标点,其N 座标为N A ,E 座标为E A ,钻完上部直井段测多点,数据经计算处理

后,井眼处于B 点,其N 座标为N B ,E 座标为E B ,则

=arctan

E A -E B

N A -N B

S =

(E A -E B )2

+(N A -N B )2

。

3 井眼轨迹控制技术

3.1 直井段轨迹控制

小位移深造斜点定向井,其直井段的防斜打快比常规定向井更为重要,直井段的井身质量的好坏直接关系到小位移定向井能否快速顺利完成。如果直井段一旦打斜,产生的位移过大,势必使下部井眼轨迹控制的调整余地减小,有可能造成方位不能兼顾双靶,造斜段长度不够等问题,使施工难度大幅度增加,甚至造成填井侧钻。

通过对江苏油田使用的各类防斜钻具组合进行优选,确定合适的直井段钻具组合。若直井段小于700m,一般采用常规钟摆钻具组合: 216mm 3A 钻头+ 159mm NDC 1根+ 159mm DC 1根+ 214mm STB+ 159mm DC 1根+ 214mm STB + 159mm DC 3柱+ 127mm 加重钻杆 10柱+ 127mmDP 。钻井参数:钻压30~80kN;转速 档~ 档;排量30L/s;泵压17MPa 。若直井段大于700m,则采用双扶刚性钟摆钻具组合,该组合适合于长直井段的钻进,既有利于控制井斜,又能解放钻压,提高机械钻速。双扶刚性钟摆钻具组合为: 216mm 3A 钻头+ 178mm NDC 1根+ 178mm DC 1根+ 197mm 多功能螺旋稳定器+ 178m m DC 1根+ 214mm

STB+ 178mm DC 2柱+ 159mmDC 1柱+

127mm 加重钻杆 10柱+ 127mm DP 。钻井参数:钻压30~140kN;转速 档~ 档;排量30L/s;泵压

22石油钻采工艺 2003年2月(第25卷)第1期

17MPa。

在直井段施工中,必须及时使用自浮式测斜仪或单点测斜仪定井深监测井眼轨迹,根据测斜结果及时调整钻井参数。起钻时,及时测多点,计算上部直井段的井眼轨迹数据,并且及时做好待钻井段设计。若待钻井段设计计算发现上部直井段井斜严重超标,产生的位移已经严重影响到下部井段的定向施工,轨迹控制难度已增加时,则必须提前定向造斜;若直井段底的闭合方位是对准靶区的,则可适当推迟定向造斜。为保证直井段的防斜打快,施工中采取了以下技术措施。

3.1.1 防斜措施

(1)施加合理钻压。根据测斜结果,及时调整钻井参数,若井斜有增大趋势时,适当降低钻压;

(2)送钻均匀,正确处理好地层交结面;

(3)每打完1根单根,上下提划2次,充分修正井壁。

由于严格执行了以上措施,较好地控制了直井段的井身轨迹,所完成各井没有因直井段的打斜而严重影响下部井段施工。

3.1.2 打快措施

(1)优选钻头型号。在较浅井段时,由于存在砾石层,使用常规 216mmXHP2B钻头或 216mm HJ517三牙轮钻头;在较深井段时,选用PDC钻头钻进。PDC钻头只需根据地层岩性选型合适、使用得当、有助于提高直井段的机械钻速有减少井斜的能力即可。

(2)优化喷嘴组合,应用高压喷射钻井技术。普遍使用中长喷嘴、斜喷嘴,在喷嘴组合上使用不等径双喷嘴组合,改善井底流场;泵压在17MPa以上。

(3)保证钻井液的粘切合适,具有良好的携砂能力,减少岩屑的重复切削。

3.2 定向造斜段轨迹控制

小位移深造斜点定向井,使用常规 弯接头+直螺杆 造斜,工具面不易转到位且不稳定,反扭角变化大,不能进行复合钻进,造斜难度大。为解决该问题,采用随钻配合单弯螺杆钻具组合造斜,该组合的优点表现为钻头使用寿命长,钻速快,钻具转动容易,工具面易到位且稳定,反扭角正常,并能通过复合钻进,充分使用好钻头,控制好狗腿角。所使用的单弯螺杆钻具组合有2种,组合(1)为单弯单稳钻具组合: 216mm3A钻头+ 165mm单弯自带稳定器导向马达+ 159mm NDC+ 159mm DC 2柱+ 127mm加重钻杆 10柱+ 127mm DP。组合(2)为单弯自带稳定器双稳钻具组合: 216mm3A钻头+ 165mm单弯导向马达+ 210~ 208mm STB+ 159mm NDC 1根+ 159mm DC 2柱+ 127mm 加重钻杆 10柱+ 127mm DP。钻井参数:钻压50 ~120kN;排量28L/s;泵压14MPa。

为保证定向造斜段具有一定的造斜率且不致 狗腿角 超标,一般选择1 ~1.25 的小角度单弯导向马达造斜,并根据实际造斜率大小,灵活调整钻井方式,使整个井段平均曲率接近于设计曲率。现场经验表明,0.75 单弯导向马达造斜率过小,而1.5 单弯导向马达则造斜率过大,复合钻进时,扭矩大,易蹩钻,较易发生钻具事故。根据定向井三维力学分析软件的理论分析及现场验证,组合(1)及组合(2)的造斜率见表2。

表2 定向造斜钻具组合造斜率

钻具组合

单弯度数

/( )

滑动钻进造斜率

/( ) (30m)-1

复合钻进造斜率

/( ) (30m)-1组合(1)1 3.86~5.191~1.5

组合(1) 1.25 4.61~6.911~1.5

组合(2)1 3.22~4.84-0.25~0.5

组合(2) 1.25 4.11~6.16-0.25~0.5 一般当设计井斜在15 内时,选用组合(2),直接造斜到稳斜角后进行复合钻进稳斜,起钻前调整好方位。当设计井斜大于15 时,采用组合(1),当造斜到一定角度(以该角度稳斜钻进能钻达目标下靶边)后,实施复合钻进增斜,起钻前调整好方位。为顺利快速完成定向造斜,采取了以下措施。

(1)定向造斜一般使用有线随钻或无线随钻监测井眼轨迹。井斜角 小于5 时,采用磁性工具面; 大于5 时,采用重力高边。

(2)钻头型号。造斜井段常使用高效HJ517三牙轮钻头,以适应单弯螺杆的高转速及复合钻进的需要;另外对应用PDC钻头进行定向造斜,进行了试验,效果良好。虽然PDC钻头钻进扭矩大,对钻压极为敏感,反扭角变化大,工具面难以控制,但使用随钻测斜仪监测工具面,送钻方法得当是可以解决此问题的。

(3)优选钻压。采用试钻法,确定最优钻压值,使机械钻速达到较高值。一般滑动钻进时使泵压比螺杆悬空泵压升高1~ 1.5MPa,复合钻进时,升高0.5MPa时,此时机械钻速普遍较高。

(4)送钻要均匀。防止反扭角波动过大而影响

23

董云安等:小位移深造斜点定向井施工技术

造斜效果,特别是用PDC钻头钻进时。

3.3 稳斜段轨迹控制

稳斜段一般使用2种钻具组合,组合(1)为常规微增钻具组合: 216mm3A钻头+ 214mm STB+ 159mm NDC 1根+ 214mm STB+ 159mm DC 1根+ 214mm STB+ 159mm DC 2柱+ 127mm加重钻杆 10柱+ 127mm DP。组合(2)为常规稳斜钻具组合: 216m m3A钻头+ 214mm STB+ 159mm DC 2m+ 214mm STB+ 159mm NDC 1根+ 214mm STB+ 159m m DC 2根+ 214mm STB+ 159mm DC 2柱+ 127mm加重钻杆 10柱+ 127mm DP。钻进参数:钻压180kN;转速60r/min;排量30L/s;泵压17MPa。

根据轨迹预测结果,如需2( )/100m的增斜率钻进才能中靶或稳斜井段为易降斜地层(如Ef4地层)时,则选用组合(1);如能稳斜中靶,则选用组合

(2)钻进。

3.4 降斜段轨迹控制

降斜段采用常规钟摆钻具组合。施工时,一般视轨迹控制情况,先以50kN钻压钻进20m,再以120 ~140kN钻压钻进。钻进过程中,使用单点测斜仪器监测井眼轨迹,视测斜情况,及时调整钻井参数或钻具组合,必要时上动力钻具降斜。

3.5 调整方位

虽然小位移深造斜点定向井能有效避免扭方位,但钻遇某些方位漂移异常的地层时,则扭一次方位也是难以避免的。钻具组合一般选用造斜钻具组合(2),扭方位成功后,实施复合钻进,以充分使用好钻头。调整方位时,要求将方位扭到靶心,可避免二次扭方位。

4 典型实例

Z22-3井为1口单目标、小靶区定向井,靶区半径为20m,其它数据见表1。设计剖面为直 增 稳三段制。直井段使用双扶正器刚性钟摆钻具,二开后1只 216mm HA437钻头钻进至1381.04m,机械钻速为20.02m/h。再以1只FM282C型PDC钻头钻达造斜点2588.13m。直井段钻进时,使用单点测斜仪监测井眼轨迹,起钻前测多点。经计算,直井段底部井眼参数为:井深2571.83m时,井斜角为2.2 ,方位角为73.41 ,垂直井深为2571.39m,累计E轴分量为30.24m,累计N轴分量为- 3.27m,闭合位移为30.42m,闭合方位为96.10 。使用定向井设计软件做好待钻井段设计,调整井身剖面设计如下:井底至靶心方位角为284.73 ,井底至靶心位移为117.43m,以15( )/100m的造斜率直接造斜到19.06 后稳斜钻进中靶。考虑邻井下部地层有减方位趋势,确定初始造斜方位角为288 。在井深2588.13m,下入定向造斜组合(1),钻头为 216mmHJ517,定向滑动造斜到2700.40m,此时井斜为19.5 ,方位为287.84 。考虑到下部地层为易降斜地层,采用微增钻具进行稳斜钻进,至井深3085m而完钻,稳斜效果较好。全井中途未扭方位,靶心距为12.03m,全井机械钻速为9.04m/h,钻井周期为23d2h,事故时效及复杂时效均为0,仅6趟起下钻钻完井深。

5 几点认识

(1)实践证明,应用小位移深造斜点定向井技术是降低定向井扭方位及更换钻具组合次数,降低定向井成本的一种有效办法。

(2)随钻测量技术与单弯螺杆钻进技术是开展小位移深造斜点定向井施工的技术保证。

(3)直井段的防斜打直是充分发挥小位移深造斜点定向井优点的关键。

(4)小位移深造斜点定向井剖面设计时,应采用适当高的造斜率,尽量下移造斜点,减少斜井段长度,以有效减少扭方位及更换钻具组合的次数。

(5)定井位时,对单靶定向井,井斜小于25 的双靶定向井及双靶挂直定向井,在地面条件及防碰绕障允许的情况下,尽可能定小位移深造斜点定向井,以降低定向井的施工成本。

参 考 文 献

[1] 周继坤.单弯滑动导向钻井的几个重要问题.石油钻探

技术,2002,30(4):25~27

[2] 张东海.濮城油田定向井综合钻井技术的应用.钻采工

艺,1997,20(2):15~17

[3] 董来明,陈小元,冯俊.导向钻具组合在江苏油田的应

用.石油钻采工艺,2001,23(3):13~15

(收稿日期 2002 11 20)

编辑 张振清

24石油钻采工艺 2003年2月(第25卷)第1期

OIL DRILLING&PRODUCTIO N TECHNOLOGY

Vol.25 No.1 Feb.2003

ABSTRACT

ROTARY C LOSED LOOP STEERABLE DRILLING SYS TEM

by Yang Jianfeng,Zhang Shaohuai(Steering Drilling Inst., Xi an Petroleum Inst.)

Abstract Rotary closed loop drilli ng technology is one of the hi techs of today s drilling industry,and it represents the direction of drilling technology in the future.The typical structures and char acteristics of rotary closed loop drilling systems at home and aboard,together with their integrating methods,downhole direc ti onal con trolling units,and surface moni tori ng systems are de scribed.The rotary steerable drilling tools have many advantages, such as continuous3D steering,extending reach i n length,i mprov ing drilling speed,shortening completion ti me,and cutti ng down drilling cost,etc.A rotary steerable closed loop drilling system MRSS developed by Steering Drilling Insti tute is presented,focuses on its direction controlling principle,five parts of composi tions, and main technical features.It stresses on the importance of devel oping and integrating drilli ng informati on and planning software.

Key words directional drilling rotary closed loop drillin g steering tool communication system monitoring system GENERAL COND ITION A ND TECHNICAL D IFFICULTIES OF EXTENDED REACH D RILLING AND ITS REQUIRE MENTS ON TOOLS AND INSTRUMENT

by Su Yi nao,Dou Xiurong(Exploration and Development Research Inst.,PetroChina)

Abstract As a newly developed comprehensive high tech drilling technology,extended reach drilling technology can effec ti vely enhance oil recovery,however,this technology is technically difficult and has higher requirements on drilling tools and instru men ts.Its definition,uses,development,technical specifications and results,economic benefits and prospects are presen ted;based on which,the basic features of extended reach drilling,its techni cal difficulties and requirements on downhole tools and instruments are further illustrated.

Key words extended reach well drilling technology drilling tool instru ment review

DR ILLING TEC HNOLOGY FOR TZ406DOUBLE STAGE HORIZONTAL WELL

by Hu Pinggong(No.2Drilling Co.of Huabei Petroleum Ad mini stration Bureau)

Abstract The aim of drilling exploratory well TZ406is to ascertain the oil bearing structures and develop the thin oil reser voirs economically.A pilot hole was drilled to verify the oil and gas reserves and locate their exact positions,and the hole was then backfilled;after backfilling,a double stage horizontal well was drilled to develop the two thin oil reservoirs at di fferent depths usin g one hole.During the whole drillin g process,only502m long of surface casing was run in hole without intermediate casing run in, and the open hole was as long as3628.83m.MWD tools were used,and by using of reversed BHA and op timizing of d r illing pa rameters,precise target hitting was achieved.The horizontal well was successfully drilled,with a measured depth of4131m,a TVD of3686.83m,well inclination of89.98 ,orientation of48.72 and horizontal displacement of538.26m.An initial production rate of86t per day was obtained after the well was pu t into production.

Key words double stage horizon tal well pilot hole side tracking combinati on d r illing reversed drilling tool

SHORT RADIUS HORIZONTAL SIDETRACKING TECH NOLOGY IN TAHE OILFIELD

by Wang Xin,Wan Jiaoyu,et al(Directional Well Co.of Drilli ng Tech.Research Inst.,Xinjiang Petroleum Administration B ureau)

Abstract The KOP in the short radius sidetracking horizon tal well in T ahe Oil field is usually located below5300m,this makes horizontal drilling very difficul t.By illustrating the technical diffi culties of drilling short radius sidetracking horizontal well,combin ing with the design and field drilling of well TK405C H,the suc cessful practices on downhole tool and instru ment modification, suitable techniques and technologies selection were presented.T he following technical difficulties such as trajectory control technology, mechanics analysis and friction/torque analysis of drill pipe in hi gh building rate in the short radius horizon tal well were also discussed, and some corresponding solutions were p roposed,which were field p roven effective.

Key words Tahe Oilfield short radius horizontal well d ynamic drill pipe trajectory control

PROPER APPLIC ATION OF AIR DRILLING IN TABNAK GASF IELD

by Liu Desheng,Zhao Shuguan g(Drilling Fluid Co.,CNPC) Abstract Air and foam drilling fluid system has much more advan tages than the conventional drilling fluid,for it enhances pen etration rate and has good lost circulation control ability.The pene tration rate by air dust drilling in the hard and dry formation can reach16.24m/h,while it is13.16m/h by mist drilli ng when the formation water production is low,and it is6.52m/h when the for mation produces more water and the pressure is relatively higher, which is comparable with that of foam drilling with penetration rate of5.23~6.63m/h.However,slight corrosi on can be caused on d rill pipe by foam drilling,while mist drilling can lead to serious corrosion.Thus suitable d rilling fluid should be selected based on the formation conditions,so that the results of i mproving penetra ti on rate and protecting drill pipe can both be achieved.

Key words mist drilling penetration rate corrosion d rilling fluid

DR ILLING TECHNOLOGY FOR D IRECTIONAL WELLS OF SMA LL D ISPLAC EMENT A ND D EEP KOP

by Dong Yun an,Chen Xiaoyuan,et al(Drilling Dept.of Jiangsu Petroleum Exploration Bureau)

Abstract The directional drilli ng technology described here can mini mize the frequency of adjus ting orientation and chan g in g B HA,thus can cu t down the costs of drilling directional wells ef fectively.This paper focuses on i ts configuration design,determi

83

Vol.25No.1 ABSTRAC T

nation of the initial orientation,well trajectory control and safety drilling technolog ies,etc.This technology has been used in30di rectional wells in Jiangsu Oilfield,with good results achieved, e.

g.,95%of the wells were free of orien tation adjustment,the fre quency of changing B HA for trajectory con trol was dramatically cut down,and the d rilling period was also shortened in certain degree.

Key words Jiangsu Oilfield small displacement deep KOP well configuration well trajectory cost

CEMENTING TECHNOLOGY USING HIGH DENSITY CE MENT IN WELL KAI 2IN QINGHAI OILFIELD

by Li Guibin,Xiu Liuyong,Zhang Zhihu(Drilling Engineer ing Co.,Dagang Oilfield Group Co.)

Abstract Cementi ng in the long isolati on section of large borehole in complex conditions can cause many problems, e.g., gas channelling,lost circulation and blowout,difficul ty of cement slurry returning to the designed depth and ineffective turbulent dis placement,etc.A laboratory test on the performances of high den sity cement slurry was conducted,and thi s test was used to simulate the complex conditions of high pressured salt bed and the coexis tence of high pressured and low pressured formations in Well Kai 2 in Katemeric Structure of Qinghai Oilfield.The high density cement was used for cementing this well,and some associate technolog ies were also applied.The results were satisfactory,and some success ful practices on cementing the long isolati on section of large bore hole in complex condi tions,and gas channelling remedy work around the annular were applied.

Key words Katemeric structure high densi ty cementin g test application

CEMENTING TECHNOLOGY OF COALBED GAS WELL IN QINSHUI BASIN

by Qi Fengzhong(Langfang Branch of Explorati on and Devel op ment Research Inst.),Li Helong,et al

Abstract Qinshui basin is abundant in coalbed gas re sources,while the cementing quality has been kept very poor, which deeply influenced the exploration and evaluation of coalbed gas in this area.The paper presents the characteri stics of coalbed gas cementin g in this area,and proposed the cementing technology suitable for coalbed gas wells.An effective fluid loss control a gent TG,wi th the property of early strength developmen t was also opti mized.The cementi ng technology and cement slurry system have been applied in10wells in Qinshui Basi n and Eerduosi Basi n,and the qualification rate was100%,in which90%of the wells were of good quality.The paper also discussed the problems need to be resolved in coalbed gas well cementing.

Key words coalbed gas cementing lightweight cement cement additive cementing quality

APPLICATION OF NITROGEN SWELLING AGENT IN CEMENTING IN SHENGLI OILFIELD

by Li Yuhai,Diao Shengxian(Yellow River Cementing Co., Shengli Petroleum Adminis tration Bureau)

Abstract Nitrogen swelling agent is vi tal for controlling gas channelling during cementing.The properties,characteristics and working mechanis ms of ni trogen s welling agent were described,and i t was used as gas channelling controlling additive in such blocks as Xianhe,Wang Jiagang,and Shengtuo in Shengli Oilfield.Field using showed that,for such wells as hi gh pressured oil and gas wells,wells of over enlarged borehole,wells with long isolation sections and some special wells,using nitrogen swelling agent is an effective way to con trol gas channeling and improve cementin g q uality.

Key words ni trogen s welling agent gas channeling ce menting quality high pressure oil and gas

HYDROGEN SULFIDE SHUTING OFF TECHNOLOGY IN WELL ZHAOX IN 2

by Pan Fengling,Liu Dongqin,et al(Drilling Tech.Research Inst.,Huabei Petroleum Administration Bureau)

Abstract As an exploration well located in the structure of Zhaolanzhuang,Well Zhaoxin 2was drilled to verify the oil and gas reserves and the resource of hydrogen sulfide.This well was com pleted in1979and oil was found oozing from the wellhead in2001. Based on the condition of high content of hydrogen sulfide and blockage of unknown matters at the wellhead,the following associ ate eq uipment such as rotary BOP,liquid/gas separator,vacuum degasser,and special tripping equipment free of killing job were used during the shutting off operation.Meanwhile,such techniq ues as closi ng the wellhead annular and pressured tripping were carried out,and the hydrogen sulfide shutting off operation in well Zhaox in 2was performed safely and successfully.

Key words Well Zhaoxin 2 shutoff hydrogen sulfide operation

EXPERIMENTAL RESEARCH ON THE PLATE MODELS FOR IM PROVING OIL RECOVERY OF RESTORED WA TER FLOOD ING AFTER POLYMER FLOOD ING by Xu Ting,Li Xiusheng(Uni versity of Petroleum,Beiji ng),et al

Abstracts Two different treatments for i mproving oil recov ery after polymer flooding have been studied with the laboratory p hysical modeling.Moreover effects of models with different perme abili ty contrasts have been considered on the technology of polymer reutilization.Then recognition of the polymer reutilizati on and ef fects has been acquired after polymer flooding.Research shows that in the treatment of polymer flooding water flooding in dep th p rofile control active water flooding,severe fingering will be produced for water mobility higher than that of polymer solution when water flooding has been restored after polymer flooding,then the s weep efficiency of water flooding has been greatly decreased.At the same time,water bulk will dilute the in depth profile control agent to great extent,which erodes the s trength of the in depth profile con trol agent,making the worse effect of profile control.In the treat ment of polymer flooding water flooding flocculati ng and fi x in g p olymer in depth profile control active water flooding,the floccu lates in site polymer diluted by water flooding,which plug hi gh permeability zones with the floc unit.The following injected poly mer fixed agen t will penetrate into the secondary hi gh permeability zone,mi x with polymer solu tion of high concentration and produce cross li nking systems which are ex cellent in in depth profile control and oil displacement.It has been testified that in plate model ex peri ments of three different permeabili ty contrasts,the polymer flocculated and polymer fixed technology is of long valid period, high strength of the floc uni t and cross linking system,the low cost,high oil recovery and utilizi ng extent of ex i sting polymer in p orous media which makes good foundation for succeeding in depth p rofile control and active water flooding.

Key words polymer flooding flocculent polymer fixed a gent in dep th profile control active water flooding plate models OPTIM IZATION METHODS OF CONCENTRATION OF HEAT GENERATION AGENTS IN IN SITU HEAT FRAC TUR ING TREATMENT

Liu Shuzhi,Sun Aiyin(South west Petroleu m Inst.),et al

Abstract Durin g fracturing treatment of oil prod uction wells

84

OI L DRILLI NG&PRODUC TION TEC HNOLOGY Feb.2003

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