1、测井资料与应用 (3),Geoscience Center, Beijing May, 2009,2.5 声波测井 (Acoustic Log),2.5.1 测量原理,* 声波发生器激发声波* 声波沿井壁滑行传播* 两个接收探头记录声波全波列信号* 测量声波传播经过两个接收探头所用的时间 t,Full wave form,Conventional acoustic log record P (compressional ), S (shear ) and stoneley wave form,compressional,常规声波测井一般提供声波时差t,GR,t,不同的地层具有不同的声波速度和时
2、差t,2.5.3 声波孔隙度,通常地层岩石骨架的声速都远大于孔隙中流体的声速高孔隙地层饱含更多的流体,其声速将较低* 记录的总 t = 骨架 t + 孔隙流体 t * 声波速度(或t ) 与孔隙度紧密相关,sound,2.5.4 应用,计算孔隙度 估算地层破裂压力地层出砂分析 计算渗透率 纵合密度测井资料制作合成地震剖面,Wyllie 平均时间公式 ( WTA )最常用的孔隙度公式 :s = 式中, tma 纯地层骨架的声波时差 ;tf 孔隙流体的声波时差;Cp 压实校正系数 .,Cp(tf tma ),(tc tma ),压实校正,固结不好(欠压实)的砂岩 t较高,用其计算的孔隙度偏高( 2
3、8 - 50%),通常需进行压实校正 压实校正公式:致密地层 Cp = 1固结不好(欠压实) 地层压实系数 Cp 0.8 1.3,压实校正图版 范例 砂岩 t = 110 s/ft 不校正 : = 40% 选择 Cp = 1.5 : 27%,泥质影响校正,固结好(压实)纱岩 :固结差(非压实)纱岩 :简单公式:,油,气影响校正 油,气的 t大于水 - 油/气层处理出的 AC 偏大油,气影响校正 系数: 气层 t = 0.7 AC 油层 t = 0.9 AC,GR,Clean sand,clean sand:tlog 125 s/fttm 55.5 s/fttf 189 s/ftCp = 1.2
4、Vsh 0.1(10%) (125-55.5)/(189-55.50)/1.2 Vsh 69.5/133.5/1.2 0.1 0.43-0.1 0.33 (%) Use cross plot: 0.3 %, calculation Using acoustic data along,t,研究岩石的物理特性,* 可用 AC 资料计算出许多岩石的弹性摸量参数 * 着些弹性摸量参数可用来评价储层压裂,出砂等问题,Borehole Breakout,Good Borehole,井壁稳定性分析,地层出砂分析,Sanding Potential Prediction,用斯通利波计算渗透率,* Permea
5、bility is a important parameter for reservoir evaluation * Permeability is difficult to calculated accurately * Stoneley wave can be used to calculate permeability more accurately,合成地震剖面,2.6 电阻率测井,A,M,N,0,测量间距,电源,电压表,B,测井仪器,电场,电阻率测井示意图,不同地层的电阻率,松软地层 (泥质砂岩) 0.5ohmm - 50ohmm. 致密地层(碳酸岩) 10ohmm to 1000o
6、hmm. 喷发岩 (硬石膏) 可高达几千到上万ohmm,Presentation,Linear scale logarithmic scale,Sand scale : 0.02 - 200,Limestone scale: 2 - 2000,2.6.3 Dual Lateral Resistivity Tool,Investigate depth- deep log RD 80 in- shallow log RS 60 in Used to calculate true formation Rt & SW,2.6.4 Induction Tool Schematic,Conductivit
7、y log Investigate depth- deep log RD 60 in- shallow log RS 40 in Used to calculate true formation Rt & SW,* 8 Rt curves with different investigation depth (10 120 in)* The logging curves separate in the permeable zone. * The invasion profile shows us the flushed zone, transition zone and virgin zone
8、.,HDIL (high resolution digital induction log),Use focused current * Very shallow investigation (2-12 in) * Measure Rt of flushed zone ( RXO) * Used for evaluation of invaded affection,2.6.5 聚焦及微电阻率测井,2.6.6 环境影响,Invaded zone,None invaded zone,泥浆侵入对地层的污染,在泥浆侵入条件下的测井响应,主要的环境影响 井眼垮塌 电阻率差异大的围岩 泥浆侵入.,The
9、 affection of bed thickness,Log pg7-4, fig 7-5,Lower Rt of surrounding bed,High Rt of surrounding bed,Bed thickness Correction ( Induction log )Bed thickness 6 ft No correctionThinner beds need more correctionDifferent Rs need different correction,Chart for borehole correction to dual lateral Exampl
10、e give: Rm = 1m RD = 10 m borehole = 11in RLLDcorr 10 1.4 14 (m),Water zone Salty mud (Rm Rxo Rm Fresh water mud (Rm Rw, high Rt invaded ) : Ra Rxo Rm Fresh water mud (Rm Rw, high Rt invaded) : Ra Rxo Rm Ra apparent log resistivity Rxo flushed zone resistivity Rm mud resistivity,Invasion affection,L
11、ow resistivity invaded,High resistivity invaded,High resistivity invasion,Rw = 0.04m/29C Rmf = 1.16m/28.5C Rt (shallower) Rt (deeper).,Low resistivity invasion,Rw = 1.14m/30C Rmf = 0.16m/27.8C Rt (shallower) Rt (deeper).,2.6.7 应用,主要用途是计算含水饱和度,识别油,气水层油/气的电阻率高于水致密岩石 (钙,硬石膏,白云岩等) 电阻率也很高, Rt 不能单独用来识别油,气,水层,Oilwater,gasoiloil,Sw,Sw,Hard rock with higher Rt value,Hard rock,CN,Thank You !,
