川东地区生物礁测井预测方法研究
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摘要
通过测井及地质资料分析,发现川东地区三叠系飞仙关组底部的泥岩纯度及厚度与下伏二叠系长兴组是否发育生物礁有密切联系,其原因是存在长兴组生物礁的地点为局部正地形,处于相对高能沉积环境,导致泥岩沉积少且不纯,因而可以根据飞仙关组底部沉积物的岩石类型和厚度来预测长兴组生物礁纵向分布。将单井测井解释的生物礁与组合式地震成像测井(CSI)资料异常区对比,根据CSI测井资料异常可预测生物礁的横向展布,并对云安14井生物礁分布作了预测。在五百梯构造长兴组生物礁体分布研究中,用地层倾角矢量点的红模式预测生物礁的主体方位,用CSI测井资料和克里金技术恢复其形态,据此预报天东71井、天东72井、天东76井在长兴组将钻遇生物礁。五百梯构造目前仅天东72井钻入长兴组,证实该井点处存在长兴组生物礁,表明多种测井方法相结合研究生物礁的横向展布及规模是可行的,CSI测井技术有明显优势。图3表2(邹冬平摘)
Trough analysis of logging and geologic data, the close relation between the purity and the thickness of the shale at the bottom of Triassic Feixianguan Group and the development of reef in underlying Permian Changxing Group in Chuandong (East Sichuan) region is found, and what caused the close relation is analyzed that the place where the reef of Changxing Group developed is a local positive landform which was in the comparatively high energy sedimentary environment which resulted in very few deposition and unpurity of shale, therefore it can predict the vertical distribution of Changxing Group reef based on the rock type and thickness of the bottom sediment of Changxing Group. The reef interpreted from logs is compared with the abnormal section of CSI logs which are used as the basis for the prediction of the transverse development and distribution of the reef and the distribution of reef in Well Yun'an 14 is also predicted. The principal azimuth of reef is forecasted by using the red pattern of vector points from dipmeter logs; the shape of reef in Changxing Group of Wubaiti structure is restored using CSI logs and Kriging technique; the presence of reef in Changxing Group in Wells Tiandong 71, 72 and 76 is predicted and this has been proved by the penetration of reef in Changxing Group in Well Tiandong 72, which shows that it is possible to study the lateral distribution and scale of organic reef by integrating many logging methods, in which CSI logging technique has its predominance obviously.
Trough analysis of logging and geologic data, the close relation between the purity and the thickness of the shale at the bottom of Triassic Feixianguan Group and the development of reef in underlying Permian Changxing Group in Chuandong (East Sichuan) region is found, and what caused the close relation is analyzed that the place where the reef of Changxing Group developed is a local positive landform which was in the comparatively high energy sedimentary environment which resulted in very few deposition and unpurity of shale, therefore it can predict the vertical distribution of Changxing Group reef based on the rock type and thickness of the bottom sediment of Changxing Group. The reef interpreted from logs is compared with the abnormal section of CSI logs which are used as the basis for the prediction of the transverse development and distribution of the reef and the distribution of reef in Well Yun'an 14 is also predicted. The principal azimuth of reef is forecasted by using the red pattern of vector points from dipmeter logs; the shape of reef in Changxing Group of Wubaiti structure is restored using CSI logs and Kriging technique; the presence of reef in Changxing Group in Wells Tiandong 71, 72 and 76 is predicted and this has been proved by the penetration of reef in Changxing Group in Well Tiandong 72, which shows that it is possible to study the lateral distribution and scale of organic reef by integrating many logging methods, in which CSI logging technique has its predominance obviously.
引文
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