Research on explaining porosity in carbonate reservoir by capture cross section method

Transcript

1 GLOBAL GEOLOGY Vol. 33 No. 4 Dec PND SIGMA CATO SIGMA CNL SIGMA CATO P A doi /j. issn Research on explaining porosity in carbonate reservoir by capture cross section method ZHAO Qin 1 MA Li-xin 2 MO Xiu-wen 1 WANG Qin-cong 2 1. College of Geo-exploration Science and Technology Jilin University Changchun China 2. Engineering Technology Institute of Northwest Oilfield Branch Company SinoPEC Urumchi China Abstract The cracks and fracture-caves are very developed in Tahe oilfield composed mainly of carbonate reservoir which affects the acquisition and accuracy of conventional logging data. When the conventional logging data can not be obtained capture cross section of PND can be used to explain the porosity of reservoir. According to the relationship among CATO saturation and porosity the authors proceed the saturation correction of SIGMA. The results of porosity calculation is better consistent with of CNL showing in correlation coefficient which proved the efficiency of porosity calculation by SIGMA with CATO and provided a new method of porosity interpretation when cracks and fracture-caves developed in carbonate reservoirs. Key words capture cross section porosity inelastic scattering measurement carbonate reservoir assessment PND C moxw@ jlu. edu. cn

2 CATO 7 CATO 3 C /O C /O CATO Σ = Σ ma 1 - φ + Σ w * S w * φ + Σ h 1 - S w * φ 2 1 φ = Σ - Σ ma - Σ Σ h * S w - Σ ma + Σ h 3 w Σ ma Σ w Σ h φ S w Σ = V i Σ i 1 i Σ Σ i i V i i 2 CATO 1 CATO PND 1 Σ 10 Table 1 Thermal macroscopic capture cross section Σ of common rock matrix and minerals C /O 11 C /O Σ c. u. Σ c. u. 12 C /O SiO ~ 14 CaMg CO ~ 9. 5 CaCO ~ 3 NaCl ~ 40 B ~ 22 Cl MPa g /L 100 CATO a b c d cm cm cm cm - 3 CATO T Σ Σ CATO 13 Σ 2

3 4 877 T = b 1 - φ + aφ 1 - S w cφs w + d 1 - φ 4 φ S w φ T φ = ad - S w ad + bc 5 + d 1 - φ 2 cφs w CATO CATO CNL CNL = a 0 + a 1 x 1 + a 2 x 2 + a 3 x 1 x 2 + a 4 x a 5 x T φ S w < % SIGMA T > % T 3 5 T 1 1 CATO T S w Fig. 1 Relationship between water saturation S w and CATO index T a 0 a 1 a 2 a 3 a 4 a 5 x 1 CATO x 2 CNL 2 A ~ m m m ~ m ~ m ~ m ~ m PND m m PND SIGMA CATO SIGMA 14 CATO SIGMA 5 CATO S w CATO 2 CNL Fig. 2 Compared of synthetic porosity with CNL multi-well SIGMA

4 PORSIGC SIGMA CATO CNL SIGMA Fig. 3 3 A807 Interpretation results of Well A J L Hai-tao DING Wen-long YUN Lu et al. Lower- Middle Ordovician carbonate reservoir karst-fracture characteristics in the southwest region of Tahe oilfield J. 2 Geoscience J. 3 CATO SIGMA CATO JING Jian-en MEI Zhong-wu LI Zhou-bo. Well-log

5 4 879 analysis on karst model of Ordovician carbonate in Tahe LI Xiao-luo MA Li-qin. Study on calculation method of oilfield J. Journal of Jilin University Earth Science reservation water saturation by PND seizing pattern J. Edition Petroleum Instruments PND-S J FAN Xiao-min LI Zhou-bo. Analysis of fluctuation and amplitude increase in sonic logs caused by fractures in carbonate rocks J. Journal of Jilin University Earth Science Edition Journal of Jianghan Petroleum Institute J SHI Xiao-zhang REN Lai-yi Q Feng-jie et al. Depositional characteristics of Triassic in northern Tarim Basin and its significance for petroleum exploration J. Global Geology M LI Zhou-bo. Borehole geophysical M. Beijing Geological Publishing House M YONG Shi-he ZHANG Chao-mo. Logging data processing and comprehensive interpretation M. Dongy- J CUI Xue-hui LIU Zhong-bao YANG Sheng-bin. Application ing Petroleum University Publishing House of Cambrian-Ordovician carbonate sequence stra- 12. J. tigraphy on petroleum exploration in Tarim Basin J. Global Geology J SONG Shan-lin CUI Min FU Heng. The logging interpretation of the Lower Ordovician solution intervals of the Tahe oilfield J. Sedimentary Geology and Tethyan Geology J YUAN Xiu-ting ZHANG Shu-jing. Application of PND well logging in carbonate reservoir in the Tahe oilfield J. West China Petroleum Geosciences J J MA Xin-zhong ZHANG Shu-jing GUO Hai-min et al. With the information of inelastic scattering of PND-S log to calculate water saturation of the reservoir J CHEN Xu-san. A new logging method for measuring. reservoir saturation and its application in Shengli oilfield J. Well Logging Technology D ZHAO Guo-zhi. Study and application of Monte Crlo. PND method in nuclear logging master's degree thesis D. Heilongjiang College of Physical Sciences and Technology of Heilongjiang University PND J GUO Hai-min ZHANG Dou-juan DAI Jia-cai et al.. PND With PND unit log data to calculate the water saturation of horizontal well reservoir J. Journal of Jianghan Petroleum Institute