錢　賡，張建民，劉傳奇，張　嵐，楊海風(fēng)，穆鵬飛，李興麗

[中海石油(中國)有限公司 天津分公司，天津 300450]

?

利用靜壓數(shù)據(jù)探討渤海海域常壓油藏砂體連通性

錢賡，張建民，劉傳奇，張嵐，楊海風(fēng)，穆鵬飛，李興麗

[中海石油(中國)有限公司 天津分公司，天津 300450]

基于同一個油藏壓力系統(tǒng)的一致性，常壓條件下地層壓力與海拔理論上的線性關(guān)系是目前判斷同一層序地層格架下砂體連通關(guān)系的重要依據(jù)。受儲層高滲與流體非均質(zhì)性的影響，判斷砂體連通性的線性規(guī)律存在局限。通過數(shù)學(xué)歸納分析，發(fā)現(xiàn)常壓油藏砂體連通關(guān)系的新方法，即建立壓力系數(shù)與海拔的反比例函數(shù)關(guān)系。根據(jù)反比例函數(shù)的相交性、單調(diào)性、有界性與對稱性，探討反比例函數(shù)性質(zhì)與油藏壓力系統(tǒng)的關(guān)系，進(jìn)一步判斷砂體的連通性。針對渤海海域7個油田、50余個開發(fā)井已證實(shí)連通關(guān)系的常壓油藏，驗(yàn)證壓力系數(shù)-海拔反比例函數(shù)性質(zhì)與砂體連通性的關(guān)系并證實(shí)：①函數(shù)圖像連續(xù)且相交重合、單調(diào)性與漸近線一致且對稱軸唯一是判斷同一層序地層格架下砂體相連通的關(guān)鍵依據(jù)；②壓力系數(shù)對分析砂體的連通關(guān)系比地層壓力的線性關(guān)系更為敏感、可靠；③函數(shù)曲率受儲層滲透性和流體性質(zhì)等影響，規(guī)避了線性規(guī)律的局限。

壓力系數(shù)；反比例函數(shù)；流體非均質(zhì)性；滲透性；常壓油藏；渤海海域

1　砂體連通性研究現(xiàn)狀

砂體連通性常用分析技術(shù)有鉆井小層對比、測井曲線特征對比、儲層地質(zhì)建模技術(shù)和單屬性描述等[1]，受海域范圍鉆井較少、儲層物性非均質(zhì)性、地震資料多解性等因素影響，上述方法應(yīng)用受到一定限制。依據(jù)同一個油藏具有統(tǒng)一的壓力系統(tǒng)，不同的油藏具有不同的壓力系統(tǒng)，利用地層壓力判斷砂體連通關(guān)系在國內(nèi)外諸多油田已經(jīng)得到了廣泛應(yīng)用[2]。

李傳亮(2005)闡述了利用地層壓力的線性關(guān)系判斷砂體連通關(guān)系的基本原理：同一個油藏任意一點(diǎn)的折算(等效)壓力都相等，即一個連通性油藏測點(diǎn)壓力位于同一條直線，且壓力折算到基準(zhǔn)面上的值是唯一的[3]。

Shaker(2001)提出利用流體剩余壓力與封存壓力定量-半定量分析砂體連通關(guān)系[4-6]。流體剩余壓力是在油藏深度剖面中地層壓力與區(qū)域性靜水壓力的差值。封存壓力是受泥巖夾層所分割的兩套儲層的壓力差值，代表泥巖夾層的封閉能力(圖1)。連通性油藏流體剩余壓力相同，不存在封存壓力。

(1)

(2)

受儲層高滲及流體非均質(zhì)性導(dǎo)致油藏頂部地層壓力數(shù)據(jù)“異常”、非同相流體剩余壓力不同(圖1)、壓力數(shù)據(jù) “分辨率不高”的影響，在實(shí)際應(yīng)用中出現(xiàn)砂體連通關(guān)系判斷“不準(zhǔn)”的現(xiàn)象，地層壓力-海拔的線性關(guān)系不足以作為決定砂體連通性的關(guān)鍵證據(jù)。

總結(jié)國內(nèi)外諸多學(xué)者關(guān)于油藏壓力與砂體連通關(guān)系的認(rèn)識，通過數(shù)學(xué)歸納分析利用電纜地層測試器在渤海海域7個油田、50余個常壓油藏取得的1 000個實(shí)測地層壓力數(shù)據(jù)[7-10]，提出利用壓力系數(shù)-海拔的反比例函數(shù)關(guān)系判斷砂體連通關(guān)系的方法，以期提高連通性分析的把握程度，為油田合理勘探開發(fā)提供關(guān)鍵依據(jù)。

圖1　油藏流體剩余壓力與封存壓力示意圖[4-6]Fig.1　Schematic diagram showing residual pressure and sealing pressure of reservoirs[4-6]

2　反比例函數(shù)性質(zhì)與連通性

根據(jù)流體力學(xué)理論，一個常壓油藏中任意點(diǎn)的實(shí)測地層壓力滿足壓力方程，即一個油藏地層壓力與海拔理論上滿足線性關(guān)系(圖2a)，地層壓力隨海拔增加而線性遞增[11-14]，如下關(guān)系式：

(3)

而另外一種分析地層壓力隨海拔變化規(guī)律的方法——壓力系數(shù)——很重要但常又被忽略。假設(shè)地層水密度恒定，經(jīng)過公式推導(dǎo)：

(4)

(5)

(6)

式中：H為海拔，m；ρw為地層水密度，g/cm3；αp為壓力系數(shù)，無量綱；a，b，c為常數(shù)。

上式是以壓力系數(shù)αp為自變量、海拔H為因變量的反比例函數(shù)的變體(圖2b)，其原函數(shù)為y=1/x(x>0，y<0)，具有相交性、單調(diào)性、有界性和對稱性4個基本性質(zhì)[15]。利用油藏壓力系數(shù)-海拔反比例函數(shù)性質(zhì)探討其油藏意義與壓力系統(tǒng)的關(guān)系、判斷同一層序地層格架下砂體的連通關(guān)系。

1) 相交性

反比例函數(shù)圖像相交重合，油藏具有統(tǒng)一的壓力系統(tǒng)，反之亦然。理論上公式(6)中b和c值相等的反比例函數(shù)圖像重合，b和c值不相等的反比例函數(shù)圖像永不相交。根據(jù)反比例函數(shù)的相交性，同一個油藏壓力系數(shù)能夠擬合到一條反比例函數(shù)曲線上，非同一個油藏則不能。

2) 單調(diào)性

隨著油藏海拔變淺，壓力系數(shù)呈現(xiàn)單調(diào)遞增趨勢(圖2b)。受重力分異作用控制，常壓油藏流體按密度分異且連續(xù)變化。在油藏高部位，因存在氣頂或油層溶解氣含量偏高，流體密度與粘度偏低，與油藏構(gòu)造深度正相關(guān)，其地層壓力高于其折算壓力(圖2a)。在油水過渡帶，隨含水飽和度增加，流體密度趨近地層水密度，地層壓力趨近靜水壓力，壓力系數(shù)逐漸接近常數(shù)。壓力系數(shù)的單調(diào)性是油藏流體性質(zhì)隨油藏深度連續(xù)變化的結(jié)果。

函數(shù)單調(diào)性決定其曲率連續(xù)規(guī)律變化，油柱高度、流體性質(zhì)和儲層物性均影響反比函數(shù)曲率變化，且不同海拔主控因素不同。Selim Simon Shaker(2014)指出淺層油藏反比例函數(shù)曲率受儲層滲透性影響，且滿足達(dá)西定律Q=-K/μ*Δp，即在流量與流體粘度一定的情況下，地層壓力變化率與滲透率滿足反比關(guān)系[4]，因此在淺層高滲儲層反比例函數(shù)曲率變化較小(圖3；表1)。而在中、深層中-低滲油藏壓力變化主要受流體密度影響，函數(shù)曲率變化相對較大(圖2b)。

圖2　油藏壓力-海拔數(shù)學(xué)模型Fig.2　Mathematical model of reservoir pressure-elevation below sea levela.地層壓力-海拔線性函數(shù)分布；b.壓力系數(shù)-海拔反比例函數(shù)分布

3)有界性

壓力系數(shù)-海拔反比例函數(shù)存在兩條漸近線(αp=1/c，H=h)，同一油藏壓力系數(shù)與油藏高度的數(shù)值分布受兩條漸近線控制，漸近線不一致的兩套砂體不屬于同一壓力系統(tǒng)。隨油藏海拔變淺，壓力系數(shù)單調(diào)遞增并無限接近于油藏頂部破裂壓力，海拔的上限值同樣趨近于最大油藏高度h。海拔增加，地層壓力逐漸偏向靜水壓力，壓力系數(shù)的下限值也無限趨近于靜水壓力系數(shù)1/c(圖2b)。

4)對稱性

反比例函數(shù)圖像是軸對稱圖形，且對稱軸唯一；連通性油藏壓力系數(shù)對稱軸唯一，對稱軸不唯一的兩套或多套砂體不屬于同一個壓力系統(tǒng)，不具有連通關(guān)系。

圖3　渤海南部KL16-X井館陶組 高滲油藏壓力系數(shù)-海拔剖面Fig.3　Profile of pressure coefficient vs. elevation of the Guantao Formation high permeable reservoirs of Well KL16-X in the southern Bohai Sea

在氣頂壓力、底水或邊水浮力等油藏驅(qū)動力的直接控制下，油藏壓力保持動態(tài)平衡狀態(tài)-壓力系數(shù)隨海拔深度的反比例函數(shù)分布。不同油藏的油柱高度、流體性質(zhì)、儲層物性等均存在差異，油藏壓力平衡條件不同，使反比例函數(shù)的性質(zhì)及意義成為判斷砂體連通關(guān)系的關(guān)鍵要素。

3　應(yīng)用與驗(yàn)證

BZ28-X油田位于渤海南部海域黃河口凹陷中央構(gòu)造脊，產(chǎn)層為新近系明化鎮(zhèn)組下段[16]。1井、3井和4井在該層系均鉆遇兩套穩(wěn)定且上下疊置砂體(圖4)，沉積相類型為河道型淺水三角洲，儲層高孔、高滲特征明顯，孔隙度分布范圍為26.6%～34.8%、滲透率分布范圍為(148.5～3 151.7)×103 μm2。

開發(fā)井在1#和2#砂體鉆遇了不同的油水界面，兩套砂體不具有連通關(guān)系。對比4井1#砂體與1井和3井2#砂體，壓力數(shù)據(jù)分布在兩條近平行的直線，反比

表1　渤海南部KL16-X井館陶組砂體地層壓力數(shù)據(jù)及 物性統(tǒng)計(jì)Table 1　Pressure and physical properties of sand bodies of the Guantao Formation of Well KL16-X in the southern Bohai Sea

注：孔隙度與滲透率均為測井解釋與儲層厚度的加權(quán)平均值。

圖4　渤海南部BZ28-X油田明下段1#和2#砂體連井對比剖面Fig.4　Cross-well correlation of sandbodies 1# & 2# in the Lower Minghuazhen Formation in BZ28-X oilfield,the southern Bohai Sea

例函數(shù)圖像不能相交重合、壓力系數(shù)不具有單調(diào)性與相同的漸近線、函數(shù)圖象對稱軸也不同(圖5；表2)，兩套砂體不屬于統(tǒng)一的壓力系統(tǒng)。

開發(fā)井證實(shí)2#砂體內(nèi)部連通，1井和3井鉆遇的2#砂體地層壓力數(shù)據(jù)均分布于一條直線，地層壓力系數(shù)共同擬合為一條反比例函數(shù)曲線(圖5b；表2)，函數(shù)形態(tài)屬于反比例函數(shù)的下半部分。反比例函數(shù)圖像相交重合、壓力系數(shù)單調(diào)性分布且函數(shù)曲率繼承性變化、可以具有共同的漸近線與對稱軸，兩套砂體壓力系統(tǒng)一致，證實(shí)了反比函數(shù)性質(zhì)及油藏意義可以作為判斷砂體連通關(guān)系的關(guān)鍵依據(jù)。

圖5　渤海南部BZ28-X油田明下段1#和2#砂體 地層壓力/壓力系數(shù)-深度剖面Fig.5　Formation pressure/pressure coefficient vs.depth of sandbodies 1# & 2# in the Lower Minghuazhen Formation in BZ28-X oilfield,the southern Bohai Seaa.地層壓力-海拔線性函數(shù)分布；b.壓力系數(shù)-海拔反比例函數(shù)分布

JZ25-X油田位于遼東灣海域西部的遼西低凸起中部[17-18]。井距僅為1km的3井和5井在古近系沙河街組三段鉆遇兩套同期發(fā)育砂體，沉積相類型為扇三角洲前緣沉積，地震上同相軸連續(xù)穩(wěn)定而且兩套砂體油層可以擬合為同一條直線上，綜合沉積儲層、地震資料認(rèn)為兩套砂體具有連通關(guān)系(圖6，圖7a；表3)。但是，目前的開發(fā)井已經(jīng)在兩井區(qū)鉆遇了不同的油水界面，證實(shí)兩套砂體不連通。

表2　渤海南部BZ28-X油田明下段1#和2#砂體地層壓力、 壓力系數(shù)與含油氣性Table 2　Formation Pressures,pressure coefficient,and hydrocarbon contents of the Neogene sandbodies 1# & 2#in the Lower Minghuazhen Formation in BZ28-X oilfield, the southern Bohai Sea

從反比函數(shù)的性質(zhì)及油藏意義的角度去探討3井、5井鉆遇的兩套砂體的連通關(guān)系。首先，壓力系數(shù)不能擬合為同一條反比例函數(shù)曲線，即函數(shù)圖像不能相交重合。其次，5井砂體壓力系數(shù)與海拔的下/上限值已經(jīng)開始趨近于靜水壓力常數(shù)與油藏高度固定，函數(shù)曲線具有明顯的漸近線，而3井砂體壓力系數(shù)曲線的漸近線與之不同、函數(shù)曲率也存在突變。最后，5井砂體壓力系數(shù)對稱性較好，與3井對稱軸不一致。綜合認(rèn)為3井、5井沙三段鉆遇兩套同期砂體屬于兩個油藏單元，彼此不連通。壓力系數(shù)對于判斷砂體連通關(guān)系更為真實(shí)。

4　反比例函數(shù)的優(yōu)勢

4.1提升高滲儲層連通性分辨能力

地層壓力與海拔的線性關(guān)系為砂體連通關(guān)系的確定提供了十分重要的依據(jù)，但是在淺層高滲儲層存在分辨能力不足的問題。根據(jù)達(dá)西定律，壓力變化率與滲透率的反比關(guān)系決定了非連通高滲砂體間流體剩余壓力相差很小、泥巖夾層封存壓力很低，線性關(guān)系不足以成為淺層高滲儲層連通性分析的關(guān)鍵證據(jù)。而壓力系數(shù)—海拔變化規(guī)律的認(rèn)識，把傳統(tǒng)的線性關(guān)系轉(zhuǎn)化為分辨率更高的反比例函數(shù)，提高了高滲砂體連通關(guān)系判斷的可靠性。

KL9-X井在淺層明化鎮(zhèn)組鉆遇兩套相鄰河流相砂體[19]，測井解釋滲透率分別2 913.7×10-3和575.1×10-3μm2(表4)，區(qū)域研究表明兩套砂體具有“一砂一藏”的成藏特征，彼此不具有連通關(guān)系。兩套砂體壓力梯度分別為1.24和1.25 psi/m，封閉壓力僅1.6 psi(圖8a)，非連通的證據(jù)不足。

圖6　渤海遼東灣JZ25-X油田3井和5井古近系沙三段砂體連井對比Fig.6　Cross-well correlation of the sandbodies in the third member of the Paleogene Shahejie Formation in Well 3 & 5 of JZ25-X oilfied,Liaodongwan offshore of the Bohai Sea

圖7　渤海遼東灣JZ25-X油田3井和5井古近系沙三段砂體地層壓力/壓力系數(shù)-深度剖面Fig.7　Formation pressure/pressure coefficient vs. depth of the sandbodies in the third member of the Paleogene Shahejie Formation in Well 3 & 5 of JZ25-X oilfield,Liaodongwan offshore of the Bohai Seaa.地層壓力—海拔線性函數(shù)分布；b.壓力系數(shù)—海拔反比例函數(shù)分布表3　渤海遼東灣JZ25-X油田古近系沙三段砂體 地層壓力數(shù)據(jù)Table 3　Pore pressure and pressure coefficient of the third member of the Paleogene Shahejie Formation in JZ25-X oilfield,Liaodongwan offshore of the Bohai Sea

井號海拔/m地層壓力/psi壓力系數(shù)3-2116.53175.41.05581-2121.53180.61.05505-2125.53184.91.05449-2130.53190.61.05389-2136.53197.11.05307-2142.53203.91.05236-2146.03207.41.05179-2150.53212.21.05116-2152.53214.41.050905-2325.53399.71.02880-2330.23403.81.02796-2336.03410.01.02728-2337.03411.21.02720-2343.53419.01.02669-2345.03421.11.02667-2347.03423.91.02663-2357.03437.31.02628-2359.03440.11.02624-2362.03444.61.02628

利用壓力系數(shù)-海拔反比例函數(shù)性質(zhì)可知：①兩套砂體壓力系數(shù)不能相交重合，無法擬合為同一個反比例函數(shù)曲線；②1#砂體函數(shù)形態(tài)較為完整，壓力系數(shù)與海拔深度均已開始趨近于兩條漸近線，而2#砂體未見其上下限；③兩套砂體函數(shù)曲率不具有連續(xù)性變化；④1#砂體反比例函數(shù)圖像的對稱軸與2#砂體不一致(圖8b)。綜合判斷，兩套砂體不具有連通關(guān)系，壓力系數(shù)—海拔的反比例函數(shù)關(guān)系對分析砂體的連通關(guān)系比線性關(guān)系更為敏感、可靠。

4.2排除連通性分析中的干擾

根據(jù)水靜力學(xué)理論，地層壓力-海拔線性關(guān)系判斷砂體連通關(guān)系僅適用于同種性質(zhì)流體，必須排除流體非均質(zhì)性的影響；而壓力系數(shù)的反比例函數(shù)分布是在氣頂壓力、底水或邊水浮力等油藏驅(qū)動力的動態(tài)平衡狀態(tài)下產(chǎn)生的，其形態(tài)的變化受油柱高度、流體性質(zhì)、儲層物性等因素控制，規(guī)避了儲層高滲與流體非均質(zhì)性對線性關(guān)系的干擾。KL9-X井1#砂體的第一個測壓點(diǎn)測井解釋為氣層，其余均為油層。受氣頂壓力及不同流體性質(zhì)影響，4個測壓點(diǎn)并不滿足地層壓力線性規(guī)律，而排出干擾因素的地層壓力線性規(guī)律明顯。非均質(zhì)性在反比例函數(shù)中轉(zhuǎn)化為對其函數(shù)形態(tài)的控制(圖8)。

5　結(jié)論

1) 壓力系數(shù)-海拔反比例函數(shù)性質(zhì)及油藏意義是探討常壓地層砂體連通性關(guān)系的新方法，其判斷標(biāo)準(zhǔn)是：反比例函數(shù)圖像連續(xù)且相交重合、單調(diào)性與漸近線一致且對稱軸唯一。

圖8　渤海南部KL9-X井明下段1#和2#砂體地層壓力/壓力系數(shù)-深度剖面Fig.8　Formation pressure/pressure coefficient vs. depth of sandbodies 1# & 2# in the Lower Minghuazhen Formation of Well KL9-X, the southern Bohai Seaa.地層壓力-海拔線性函數(shù)分布；b.壓力系數(shù)-海拔反比例函數(shù)分布表4　渤海南部KL9-X井明化鎮(zhèn)組砂體地層 壓力與含油氣性統(tǒng)計(jì)Table 4　Pressures,permeability and hydrocarbon contents of the Neogene Minghuazhen Formation in Well KL9-X, the southern Bohai Sea

砂體海拔/m地層壓力/psi壓力系數(shù)平均滲透率/(×10-3μm2)測井解釋1#-1133.01623.41.02758-1140.01624.91.02209-1142.01627.41.02184-1144.01629.91.021552913.7氣層油層油層油層2#-1159.61651.11.02069-1161.01652.91.02051-1162.01654.11.02039575.1油層油層油層

注：孔隙度與滲透率均為測井解釋與儲層厚度的加權(quán)平均值。

2) 相比地層壓力-海拔線性關(guān)系，壓力系數(shù)-海拔反比例函數(shù)變化規(guī)律對分析同一層序地層格架中砂體連通性更加可靠。

3) 渤海海域常壓油藏壓力系數(shù)反比例函數(shù)曲率受油柱高度、流體性質(zhì)、儲層物性等因素控制，規(guī)避了儲層高滲與流體非均質(zhì)性對地層壓力線性關(guān)系的干擾。

[1]劉傳奇,呂丁友,侯冬梅.渤海A油田砂體連通性研究[J].石油物探,2008,47(3):251-255.

Liu Chuanqi,Lv Dingyou,Hou Dongmei.Study of connectivity of sand bodies in oilfield A,Bohai area[J].Geophysical Prospecting for Petroleum,2008,47(3):251-255.

[2]Mark D.Zoback.Reservoir geomechanics[M].New York：Cambridge University Press,2007：3-55.

[3]李傳亮.油藏工程原理[M].北京：石油工業(yè)出版社,2005,11：5-7.

Li Chuanliang.Fundamentals of reservoir engineering[M].Beijing：Petroleum Industry Press,2005,11：5-7.

[4]Selim Simon Shaker.Reservoir vs.seal pressure gradients:Calculations and pitfalls[C]// American Association of Petroleum Geologists，AAPG 2014 Annual Convention & Exhibition.Houston:Omnipress，2014:1834685.

[5]Selim Simon Shaker.Geopressure compartmentalization in Keathley Canyon deep water,Gulf of Mexico[J].Comparative Drama,2005,39(2):131-156.

[6]Leonardo Enrique Aguilera Gomez,Francisco Espitia Hernandez,Devendra Kumar,et al.Understanding pressure compartmentalization in Ultra deep-water drilling off Mexican Gulf Coast:A case study[C].// American Association of Petroleum Geologists,AAPG 2014 Annual Convention & Exhibition,Houston:Omnipress.2014:1841804.

[7]潘福熙.ERCT電纜地層測試器應(yīng)用實(shí)例研究[J].國外測井技術(shù),2012(4):45-48.

Pan Fuxi.Research of the ERCT wireline formation tester application[J].World Well Logging Technology,2012,(4):45-48.

[8]馬建國,符仲金.電纜地層測試器原理及其應(yīng)用[M].北京：石油工業(yè)出版社,1995:1-174.

Ma Jianguo,Fu Zhongjin.Principles and applications of wireline formation tester[M].Beijing：Petroleum Industry Press,1995：1-174.

[9]陳永生,譚廷棟.地層壓力理論與評價-壓力計(jì)算參考書[M].北京：石油工業(yè)出版社,1990:1-157.

Chen Yongsheng,Tan Tingdong.The pressure log reference manual-Theory and evaluation of formation pressure[M].Beijing：Petroleum Industry Press,1990:1-157.

[10]王昌學(xué),曹文利,王向榮.電纜地層測試壓力梯度的計(jì)算與應(yīng)用[J].石油勘探與開發(fā),2008,35(4):476-481.

Wang Changxue,Cao Wenli,Wang Xiangrong.Pressure gradient computation and application of wireline formation tester[J].Petroleum Exploration and Development,2008,35(4):476-481.

[11]匡立春.電纜地層測試資料應(yīng)用導(dǎo)論[M].北京:石油工業(yè)出版社，2005:1-140.

Kuang Lichun.An introduction to applied of the wireline formation data[M].Beijing:Petroleum Industry Press,2005:1-140.

[12]匡立春,毛志強(qiáng),孫中春,等.基于新技術(shù)的油氣藏測井綜合評價[J].石油勘探與開發(fā),2003,30(2):58-60.

Kuang Lichun,Mao Zhiqiang,Sun Zhongchun,et al.Reservoir synthetic evaluation based on new loging technology[J].Petroleum Exploration and Development,2003,30(2):58-60.

[13]Thomas Finkbeiner,Mark Zoback,Peter Flemings,et al.Stress,pore pressure,and dynamically constrained hydrocarbon columns in the South Eugene Island 330 field,Northern Gulf of Mexico[J].AAPG Bulletin,85(6):1007-1031.

[14]Walter H.Fertl.Abnormal formation pressures-Implications to exploration,drilling,and production of oil and gas resources[M].Amsterdam:Elsevier Scientific Publishing Company,1976:1-349.

[15]課程教材研究所.數(shù)學(xué)(八年級下冊)[M].人民教育出版社，2008:38-62.

Course materials research institute.Mathematics(grade eight)[M].Beijing:The People's Education Press,2008:38-62.

[16]鄧運(yùn)華,王應(yīng)斌.黃河口凹陷淺層油氣成藏模式的新認(rèn)識及勘探效果-來自BZ28-2S油田勘探歷程的啟示[J].中國石油勘探,2012,17(1):25-29.

Deng Yunhua,Wang Yingbin.New recognition of shallow oil and gas reservoir forming mode and exploration achievements in Huanghekou Sag-Enlightenment from exploration process of BZ28-2S oilfield[J].China Petroleum Exploration,2012,17(1):25-29.

[17]祝春榮,韋阿娟,沈東義.遼東灣地區(qū)錦州25-1油田油氣成藏特點(diǎn)和運(yùn)聚模擬研究[J].海洋石油,2011,31(3):17-22.

Zhu Chunrong,Wei A’juan,Shen Dongyi.Pooling characteristics and hydrocarbon migration and accumulation modeling research in JZ25-1 oilfield in Liaodongwan area[J].Offshore Oil,2011,31(3):17-22.

[18]周心懷,余一欣,魏剛,等.渤海遼東灣海域JZ25-1S轉(zhuǎn)換帶與油氣成藏的關(guān)系[J].石油學(xué)報(bào),2008,29(6):837-840.

Zhou Xinhuai,Yu Yixin,Wei Gang,et al.Relationship between JZ25-1S transfer zone and hydrocarbon accumulation in Liaodongwan offshore of Bohai Bay Basin[J].Acta Petrolei Sinica,2008,29(6):837-840.

[19]彭文緒,孫和風(fēng),張如才,等.渤海海域黃河口凹陷近源晚期優(yōu)勢成藏模式[J].石油與天然氣地質(zhì),2009,30(4):510-518.

Peng Wenxu,Sun Hefeng,Zhang Rucai,et al.Late-stage near-source preponderant hydrocarbon pooling pattern in the Huanghekou Sag of the Bohai Sea waters[J].Oil & Gas Geology,2009,30(4):510-518.

(編輯張玉銀)

A study on sand bodies connectivity in normal pressure reservoirs of the Bohai Sea with hydrostatic pressure data

Qian Geng,Zhang Jianmin,Liu Chuanqi,Zhan Lan,Yang Haifeng,Mu Pengfei,Li Xingli

(CNOOCTianjinCompany,Tianjin300450,China)

Based on the consistency of pressure system within the same reservoir,the theoretical linear relationship between formation pressure and depth is currently used as an important criterion to determine the connectivity of sand bodies within the same sequence stratigraphic framework under normal pressure.However,the linear rule for determining sandbodies connectivity has its limitations due to the influences of high permeability and fluid heterogeneity of reservoir.A new method for connectivity analysis of sand bodies is proposed based on mathematical induction,established the inverse proportional function between pressure coefficient and depth of reservoir.The properties of inverse proportional function such as intersection,monotonicity,boundedness and symmetries provide us a way to explore the relationship between inverse proportional function and reservoir pressure system,and to further determine the connectivity of two or more sand bodies.With hydrostatic pressure data from more than 50 normal pressure reservoirs out of 7 oilfields in Bohai Sea whose connectivity have been confirmed by wells,we verified the relationship between the connectivity of sand bodies and the properties of inverse proportional function of pressure coefficient and depth.The following conclusions were made.① The function image being continuous and overlapping,monotonicity and asymptote being consistent,and symmetry axis being unique are the critical criteria for determining the connectivity of sand bodies within the same sequence stratigraphic framework;② The pressure coefficient is more sensitive and reliable than the linear function;③ The curvature of inverse proportional function is affected by reservoir permeability and fluid properties,thus overcomes the limitations of linear rule.

pressure coefficient,inverse proportional function,fluid heterogeneity,permeability,normal pressure reservoir,Bohai Sea

2015-10-21;

2016-03-23。

錢賡(1986—)，男，碩士、工程師，油氣田勘探與開發(fā)地質(zhì)。E-mail:qiangeng@outlook.com。

國家科技重大專項(xiàng)(2011ZX05023-006-002)。

0253-9985(2016)04-0584-07

10.11743/ogg20160416

TE122.2

A