地质导向中二维储层界面预测方法研究

A Method to Predict 2D Reservoir Interfaces in Geosteering

王谦 李国利 李震 苏波 洪英霖

Wang Qian Li Guoli Li Zhen Su Bo Hong Yinglin

中国石油测井有限公司, 陕西西安 710077; 中国石油塔里木油田分公司, 新疆库尔勒 841000

CNPC Logging Co., Ltd., Xi’an, Shaanxi, 710077, China; PetroChina Tarim Oilfield Company, Korla, Xinjiang, 841000, China

目前常用的钻前地质导向模型建立在地震资料精细处理的基础上,分辨率较低,需要建立一种新的储层界面预测方法.以测井资料为基础,建立了地层视倾角的计算方法,通过平移、创建虚拟井等方式确定水平井钻进方向上的地层边界信息,构建地层边界模型,推导了地层边界的数学关系.应用地层视倾角预测模型和不同井位分布下的地层边界数学模型进行了现场预测,结果表明,目的层视倾角为0.70°,完井计算地层视倾角为0.53°,误差较小;储层边界预测结果与实测结果误差为0.1~3.6 m,预测结果受地层变化情况的影响较大.研究表明,地层边界深度是水平位移的函数,下倾地层边界深度与水平位移呈线性正相关,与建模井的井距呈线性反相关,而上倾地层变化规律与之相反;对于地层厚度逐渐变化的地层,数学建模预测结果比视厚度预测结果更为准确.研究结果为水平井地质导向提供了一种直观量化的指导方法.

Current pre-drilling geosteering models are often built through fine seismic data processing, with low resolution. So, it is necessary to develop a high accuracy method to predict a reservoir interface. Based on logging data, a calculation method of apparent formation dip was proposed. A reservoir boundary model was constructed and the mathematical relationship of reservoir boundary was deduced by means of translation and virtual wells to determine the reservoir information on horizontal well direction. The prediction model of apparent formation dip and the mathematical model of reservoir boundary under different location distributions have been used in oil fields. The results showed that the apparent formation dip of target stratum predicted on site was 0.70°, and the apparent formation dip calculated upon well completion was 0.53°, indicating a minor error. The predicted result with the mathematical model of reservoir boundary had an error of 0.1-3.6 m with the measured result, which was significantly affected by formation changes. The research suggested that the depth of formation boundary was a function of horizontal displacement. For the downdip formation, there was a linear positive correlation between the boundary depth and the horizontal displacement. Further, there was a linear negative correlation between the boundary depth and the distance from modeled well. For the updip formation, the changes were opposite. For the formation in which thickness changed gradually, the mathematical model provided more accurate prediction results than the apparent thickness method. The reservoir interface prediction results could provide direct and quantitative guidance for horizontal well geosteering.

国家科技重大专项"复杂储层油气测井解释理论方法与处理技术"(编号:2011ZX05020-008)部分研究内容.

https://doi.org/10.11911/syztjs.201503017