(1+机理 影响因素 解除)水锁效应对低渗透储层的损害及抑制和解除方法

3廖锐全,1962年生,1984年大学毕业,在读博士,副教授;主要从事采油工程的教学和科研工作,在国内外刊物上发表论文28篇,参编专著3部。

地址:(434023)湖北省荆州市江汉石油学院石油工程系。

电话:(0716)8430457。

E -mail :liaoruiquan
@
水锁效应对低渗透储层的损害及抑制和解除方法
廖锐全3 徐永高 胡雪滨　
(江汉石油学院) (中国石油长庆油田公司) (中国石化江汉油田分公司)
廖锐全等.水锁效应对低渗透储层的损害及抑制和解除方法.天然气工业,2002;22(6):87～89
摘　要　低渗透特低渗透油藏普遍存在着水锁损害,而且渗透率越低,水锁伤害越严重;造成水锁效应有内在和外在两方面的因素。

储层致密、孔隙喉道小,油藏压力低、存在绿泥石薄膜状的孔隙衬边结构是造成储层产生水锁效应的内在因素;驱动压差小、外来流体与岩石的润湿角小、粘度大及油水界面张力大是造成储层产生水锁效应的外在因素。

渗透率越低,孔喉半径越小,油层压力越低,越容易产生水锁损害,且越难以解除其损害。

通过室内实验研究认为:提高排液速度可以提高渗透率的保留率,抑制水锁效应;向油层中挤注一定的表面活性剂体系工作液,可以有效地提高油相渗透率的保留率,减弱和部分消除水锁效应;在注入水中加入优化后的表面活性体系,可
层,存在很强的水锁效应,而且渗透率越低,水锁伤害越严重。

造成水锁效应的因素分析
水锁效应就其本质是由于存在毛细管压力而产
系数0.65～0.75,储层岩石为弱亲水—中性。

储层胶结物含量较高(绝对含量达11.5%);据铸体薄片和扫描电镜分析,该储层主要以次生孔隙为主,粒间溶孔较发育,粒内溶孔多见于长石、云母、绿泥石内,孔喉类型为变窄的孔隙和片状喉道,总面孔率仅6%～9%。

由毛管压力曲线分析可知,该储层为典型的
・
78・第22卷第6期 天　然　气　工　业 开发试采
特低渗透油层,平均孔喉半径0.38～0.95μm ,非均质性严重,主要流动孔喉体积相对较小,仅占30%～41%。

由此可见,JA 油田长6油层压力低,孔喉微细,存在绿泥石薄膜状的孔隙衬边结构,这是造成外来流体侵入引起含水饱和度上升而使油相渗透率下降的内在原因。

2.
造成水锁效应的外在因素分析
按照毛管束模型,当储层亲水时,在毛管压力作用下,外来流体侵入,根据Laplace 公式和Poiseuille 定律,可得到在压差Δp (Pa )作用下,将半径为r (m )的毛细管中长度为L (m )的外来流体排出所需要的时间T (s )为:
T =4μL
2r 2
Δp -2σr cos
θ1.提压反排实验
首先抽空岩心并饱和煤油,在一定排量下测定煤油渗透率;而后反向注水,测定水的渗透率;再在同一排量下测煤油渗透率,最后提高排量再测煤油渗透率,观察用提压反排方法抑制水锁效应造成伤害的效果。

实验结果见表2。

表2　提压反排实验数据表
岩　心
Z J18-22Z J18-18K g (10-3μm 2
) 1.62
5.35
排 量(mL/min )渗透率(10-3μm 2)渗透率保留率(%)渗透率10-3μm 2渗透率保留率(%)
煤　油0.50.618100 2.440100注入水0.5
0.324/ 1.123/煤　油
0.5110115
0.1730124601271
28.0391*******
0.5340195911214
21.873913149178
由表2可知,提高排液速度可以增加油相渗透率,提高渗透率的保留率。

在油藏实际开发中,则一方面,当钻井滤液等外来流体侵入油层后,应提高反排速度,减小其侵入的深度,从而减弱因外来流体侵
入造成的水锁效应;另一方面,在水驱过程中应提高驱动压力梯度,削弱水锁损害,提高油相渗透率。

2.挤注放差实验
向已产生水锁效应的岩心中挤注一定浓度的表面活性剂,关闭一定时间后,再在同一排量下测煤油渗透率,实验结果见图1。

图1,压裂等增产措施时应采用低表面张力液。

3.化学方法改善低渗透油层的渗流特征实验低渗透油藏流体因存在初始压力梯度,不满足达西渗流规律,而出现出非线性渗流特征。

图2为两组迭加的油水相对渗透率曲线,一组是原油与注入水的相对渗透率曲线,另一组为原油与加表面活
图2　油水相对渗透率曲线
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88・开发试采 天　然　气　工　业 2002年11月
对本实验而言,用这种方法可以提高采收率6.9%。

这主要是因为表面活性剂体系可以改变低渗透油层中流体的渗流特性,增加注入水的初始压力梯度,减少原油渗流的初始压力梯度,使油水流度更加接近,减少油的“卡断”现象,从而改善低渗透油藏的水驱开发效果。

结 论
1)储层致密、孔隙喉道小,岩石颗粒表面覆盖绿
泥石等易水化的薄膜,且油藏压力低、生产压差小是造成储层产生水锁效应的内在因素。

而驱动压差
小、外来流体与岩石的润湿角小、表面张力大和粘度大是造成储层产生水锁效应的外在因素。

2)提高外来侵入流体的反排速度,减小其侵入
性剂,用清水顶替后关井一定时间,然后开井放差生产,同时降低回压,可以解除水锁效应所造成的损害。

4)优化后的表面活性剂体系可以改变低渗透油层中流体的渗流特性,减少水驱过程中原油的“卡断”现象,改善低渗透油藏的水驱开发效果。

参　考　文　献
1　樊世忠等著.钻井液完井液及保护油气层技术.山东东
营:石油大学出版社,1996:524～530
2　贺承祖,华明琪.水锁效应研究.钻井液与完井液,1996;
13(6):13～15
(收稿日期　2002-06-18　编辑　
韩晓渝) 3王登海,1969年生,工程师;1994年毕业于西南石油学院天然气加工专业;现在西安长庆科技工程有限责任公司(原长庆石油勘察设计研究院)从事天然气净化的设计工作,并担任长庆气田第二、三天然气净化厂工程设计项目负责人。

地址:
(710021)陕西省西安市未央区兴隆园小区长庆科技工程有限公司。

电话:(029)6593978。

长庆气田地面工程技术现状介绍
王登海3
(西安长庆科技工程有限公司)
王遇冬
(西安石油学院)
王登海等.长庆气田地面工程技术现状介绍.天然气工业,2002;22(6):89～92
摘　要　中国长庆气田所生产的商品天然气主要输往北京、天津、西安、石家庄、银川等城市作为民用燃气,部分用于发电和化工原料(例如合成甲醇)等。

长庆气田主要包括靖边、榆林、乌审旗及苏里格等气田,其中靖边气田已建成产气规模34×108m 3/a 。

在简述了长庆气田主要基础条件诸如天然气性质、单井配产及地面自然条件等之后,着重介绍了具有长庆气田特点的地面工程技术现状及今后发展设想,其中包括高压集气、脱硫脱碳、酸气处理、低温分离及其他配套的小型发电、甲醇集中回收技术,以及今后回收CO 2的初步想法等。

主题词　长庆气田　地面工程　技术　现状　发展
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98・第22卷第6期 天　然　气　工　业 工程建设
USE D FOR JINGBIAN G AS FIE LD AN D ITS AP2 PL ICATION IN PR OD UCTIVIT Y CONSTRUC2 TION
Wang Y ong,Wang Hong,Wang Caili and Yang Y ong(Research Institute of Exploration and Devel2 opment,Changqing Oil Field Branch,PCL). N A TU R.GA S IN D.v.22,no.6,pp.80～83,11/25/ 2002.(ISSN100020976;In Chinese)
ABSTRACT:The optimizing well spacing technique used for Jingbian gas field is a comprehensive well spacing technique of applying multiple disciplines as seismics,geology,well logging and gas reservoir engineering in light of these geological charac2 teristics of Low Paleozoic gas reservoir,such as large burial depth,wide gas2bearing2area,complicated erosional groove dis2 tribution,thin gas2bearing layer,strong heterogeneity greatly changeful individual well production,etc.Its core,videa is to take the monographic studies of multiple disciplines as the basis and the discipline branching point as the cutting2in point so as to attain the goal of optimizing the well spacing at last through the combination of microcosm with macrocosm,the combination of dynamic behavior with static behavior and the synthesis of mul2 tiple disciplines.In the paper,it is pointed out that the erosonal groove distribution characteristics and reservoir thickness may be identified by seismic research,thus laying a material founda2 tion for optimizing well site;in light of the geological research on the formation mechanism of the karstic reservoir beds in Lower Paleozoic gas reservoirs,the major control factors of gas reservoir formation were successfully determined and the gas2richening areas were found out,thus pointing the way out for selecting op2 timal well spacing regions;in gas reservoir engineering research, mainly based on gas well producing performance data,the high2 permeability fluid connecting areas were accurately divided up by closely combining with the pressure system theory,thus pro2 viding necessary dynamic data for designing well spacing and optimizing well site in various regions;and,on the basis of the research results of various disciplines,the beneficial well spacing regions and development well site deployment were optimized fi2 nally by synthetically considering the gas2richening areas and reservoir fluid connecting areas.Through productivity construc2 tion implemented in1999～2000,it was proved that the techni2 cal idea and method of optimizing well site are correct and have great economic returns.
SUB JECT HEADING S:Changqing Oil Field,Late Palaeo2 zoic Era,G as reservoir,High productivity well,Well spacing, Optimization,Productivity
W ang Yong(M aster,engineer),born in1968,is mainly engaged in the research on development geology and well site deployment and published over ten articles.Add:Changqing Xinglongyuan Quarter,Xi’an,Shaanxi(710021),China　Tel: (029)6593526
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NEW UN DERSTAN DING OF THE BIN OMIAL CO2 EFFICIENT“B”OF G AS WE LL
Hao Yuhong and Chen Tiaosheng(Research In2 stitute of Exploration and Development,Changqing Oil Field Branch,PCL).N A TU R.GA S IN D.v.22, no.6,pp.84～86,11/25/2002.(ISSN100020976;In Chinese)
ABSTRACT:In the process of gas well productivity test2 ing,people often considered the binomial coefficient“B”as a constant after the disappearance of reservoir effects in well bore. Through practice,however,it was proved that the binomial co2 efficient“B”determined on this condition is of a large error.In the paper,on the basis of the binomial productivity general for2 mula,the change law of the binomial coefficient“B”is theoreti2 cally derived in consideration of the investigation radius and its corresponding permeability change.In other words,the influence of the investigation radius and its corresponding permeability on the binomial coefficient“B”is only manifested at the reservoir effect stage of well bore,i.e.the change of the coefficient“B”is obvious at the stage;when the investigation radius is enlarged to a certain extent(of course the reservoir effects of well bore have disappeared),the influence of the investigation radius and its corresponding permeability will be smaller and smaller,then trend towards a constant gradually,which plays an important guiding role in carrying out gas well productivity test design and obtaining stable and reliable productivity equation and open2flow capacity.
SUB JECT HEADING S:G as well,Binomial,Coefficient,In2 vestigation range,Radius,Well bore,Permeability
H ao Yuhong(engineer),born in1965,graduated in reser2 voir engineering from Xi’an Petroleum Institute in1991,won ministerial,provincial and bureau’s scientific and technological progress prizes for several times and published over30articles. Now he is engaged in the research on gas field development. Add:Changqing Xinglongyuan Quarter,Xi’an,Shaanxi (710021),China　Tel:(029)6593526
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DAMAGE T O LOW2PERMEABI L IT Y RESERV OIR B Y WATER LOCKING EFFECT AN D ITS IN2
01
N A TU RA L GA S IN DUS T R Y/November,2002
HIBITING AN D REMOVING METH ODS
Liao Ruiquan(Jianghan Petroleum Institute), Xu Y onggao(Changqing Oil Field Branch,PCL)and Hu Xuebin(Jianghan Oil Field Branch,Sinopec). N A TU R.GA S IN D.v.22,no.6,pp.87～89,11/25/ 2002.(ISSN100020976;In Chinese)
ABSTRACT:The water2locking damage is commonly found in specially low2to2low permeability oil reservoirs and the lower the permeability,the more serious the damage by water locking.There are two aspects of factors,i.e.internal factors and external factors,in forming water locking effect.The inter2 nal factors include compact reservoir,small pore throats,low reservoir pressure and existent thin2film chlorite pore lining structure;and the external factors are composed of poor driving pressure difference,a small wetting angle of rock with extrane2 ous fluid,high viscosity,and large oil2water interface tension. The lower the permeability and the smaller the pore2throat ra2 dius as well as the lower the reservoir pressure,the easier the formation of water locking damage,and it is difficult to be re2 moved.Through experimental study in laboratory,it was consid2 ered that the reservation rate of permeability may be raised by speeding up fluid discharge,thus inhibitting the water locking effect;through injecting a certain of surfactant system treatment fluids into oil reservoir,the reservation rate of oil2phase perme2 ability can be effectively raised,thus weakening and partially re2 moving the water locking effect;by means of adding optimized surfactant system into the injected water,the percolation charac2 teristics of the fluids in low permeability oil reservoir can be changed and the oil2water concurrent flowing area may be effec2 tively enlarged,thus improving the development effectiveness of water drive oil reservoir.
SUB JECT HEADING S:Reservoir,Water lock,Formation damage,Surfactant,Oil displacement efficiency,Development effectiveness
Liao Ruiqu an(associate prof essor),born in1962,graduat2 ed from an university in1984,Now he is studying for his doc2 torate and mainly engaged in the teaching and research on oil production engineering.He published3books and28articles in domestic and foreign periodicals.Add:Jingzhou,Hubei (434023),China　Tel:(0716)8430457
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PRESENT SITUATION AN D ENVISAGEMENT OF THE SURFACE ENGINEERING IN CHANGQING2 G AS FIE LD
Wang Denghai(Changqing Scientific and Tech2nological Engineering Co.Ltd.)and Wang Yudong (Xi’an Petroleum Institute).N A TU R.GA S IN D. v.22,no.6,pp.89～92,11/25/2002.(ISSN10002 0976;In Chinese)
ABSTRACT:Being taken as domestic gas and partially as industrial gas(e.g.power generation,synthetic methanol), etc.,the marketable natural gas produced from Changqing G as Field is mainly transported to the following cities as Beijing, Tianjin,Shijiazhuang and Y inchuan,etc.Changqing G as Field is mainly composed of Jingbian,Yulin,Wushen Banner and Sulige gas fields,in which a scale of3400×106m3/d has been built up in Jingbian gas field.Affer the principal basic circumstances, such as gas property,individual2well proration and natural con2 dition,in Changqing G as Field are simply stated,the present sit2 uation and envisagement of the surface engineering,including high pressure gas gathering,desulfurization,decarbonization, sour gas treatment,cryogenic separation and the other necessary small2size power2generating and methanol centralized recovery techniques,as well as a primary idea of recovering CO2in the fu2 ture,etc.,in Changqing G as Field are emphatically introduced in the paper.
SUB JECT HEADING S:Changqing G as Field,Surface en2 gineering,Technique,Status quo,Developing trend
W ang Denghai(engineer),born in1969,graduated in nat2 ural gas processing from the S outhwest Petroleum Institute in 1994.Now he is engaged in the design of natural gas purifica2 tion and is the person in charge of the engineering design pro2 jects of No.2and No.3Natural G as Purification Plants.Add: Xinglongyuan Qarter,Xi’an,Shaanxi(710021),China　Tel: (029)6593978
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RESEARCH AN D APPL ICATION OF AMINE2G AS DESU LPHRIZATION TECHNIQUES IN CHANGQING G AS FIE LD
Wang Yudong(Xi’an Petroleum Institute)and Wang Denghai(Changqing Scientific and Technologi2 cal Engineering Co.Ltd.).N A TU R.GA S IN D.v. 22,no.6,pp.92～96,11/25/2002.(ISSN100020976; In Chinese)
ABSTRACT:Five sets of2×106m3/d and one set of4×106m3/d MDEA desulphrization devices were built up in Changqing G as Field,however,the CO2content in the purified gas didn’t satisfy the pipeline transportation standard because of high H2S2CO2ratios(90～160).For this reason,on the basis of analyzing the methyl diethanolamine(MDEA)selective desul2 phurization techniques applied in Changqing G as Field at pre2 sent,S ome improved opinions about the techniques of the desul2
11
N A TU RA L GA S IN DUS T R Y/November,2002 。