Abstract:
Sandstone and conglomerate reservoir affected by fluid abnormal overpressure in deep layer is one of the focuses in petroleum exploration and reservoir study.Drilling and oil production test data show that abnormal pressure exists widely in the Paleogene Shahejie Formation，and has closely related with oil-bearing and oil productivity of the sandstone and conglomerate reservoir.In this study，formation pressure in different strata and different zones were calculated with equivalent depth method using logging data calibrated by oil production test data.Calculating results show that formation pressure in the lower Submember of Member 3 of Shahejie Formation(Esx3)is the largest，and its residual formation pressure equals 15-30 MPa. According to the statistics on sandstone and conglomerates porosity and their residual formation pressure，the porosity increases 2％ when formation pressure increases 5 MPa.Therefore，the sandstone and conglomerates porosity in Esx3 may be increased by 4％-10％.Integration of microcosmic reservoir characteristics and porosity interpretation of logging data，three factors improving deep sandstone and conglomerate reservoir are listed as follows:(1)fluid abnormal pressure protects primary and secondary pores formed in early periods，(2)overpressure environment produces acidic groundwater into reservoir and forms dissolution pores，(3)fluid abnormal overpressure promotes the formation of microfractures，and improves the seepage capacity.
Key words:
abnormal overpressure,
sandstone and conglomerate reservoir,
deep layer,
Paleogene,
Chezhen Sag
摘要： 受流体异常高压影响而发育的异常孔隙（砂）砾岩储集层成为深层油气储集层和油气勘探研究的热点之一。测井、钻井及试油结果揭示，车镇凹陷古近系沙河街组广泛存在流体异常高压，且与（砂）砾岩储集层含油性及产能具有密切关系。在试油地层压力实测数据标定下，利用测井资料等效深度法对古近系沙河街组分层系、分地区进行了地层压力计算。计算结果表明，古近系沙河街组三段下亚段（Esx3）地层压力异常程度最大，剩余地层压力达15～30 MPa。重点钻井中（砂）砾岩储集层孔隙度与对应层段剩余地层压力统计分析表明，地层压力在5 MPa以上时开始对孔隙度产生影响，每增加5 MPa孔隙度大约增大2％，据此推测Esx3由于异常高压的存在，（砂）砾岩储集层孔隙度可增加4％～10％。结合微观储集层特征和测井资料的孔隙度解释结果，分析导致该区深层储集层储集性能得以改善的原因包括：（1）异常高压有利于原生孔隙及早期次生孔隙的保存；（2）超压环境有利于酸性地层水进入储集层形成溶蚀孔隙；（3）流体异常高压有利于微裂缝的产生，增强孔隙间连通性和渗流能力。
关键词:
异常高压,
（砂）砾岩储集层,
深层,
古近系,
车镇凹陷
CLC Number:
Xian Benzhong, Wu Caixi, She Yuanqi. Fluid abnormal overpressure and its influence on deep clastic reservoir of the Paleogene in Chezhen Sag of Dongying, Shandong Province[J]. JOURNAL OF PALAEOGEOGRAPHY, 2011, 13(3): 309-316.
鲜本忠, 吴采西, 佘源琦. 山东东营车镇凹陷古近系流体异常高压及其对深层碎屑岩储集层的影响*[J]. 古地理学报, 2011, 13(3): 309-316.