NBR油田优质储层叠前叠后联合反演与应用

Pre-stack and post-stack joint inversion and application of high-quality reservoirs in NBR oilfield

开展NBR油田地震优质储层预测,可有效支撑低效井区开发和外扩区储量动用,对油田产能建设有重要意义.本文针对地震反演存在叠后反演参数单一、叠前反演多解性强的问题,提出三步流程实现叠前叠后联合反演,达到优质储层定量表征目的.步骤一通过叠后地质统计学反演预测砂泥岩;步骤二开展岩石物理分析,明确了剪切模量为含油砂体敏感弹性参数,再以步骤一反演结果为约束,采用叠前扩展弹性阻抗反演(EEI)预测储层含油性;步骤三仍以步骤一结果为约束,采用高斯配置协模拟测井参数反演预测孔隙度、渗透率.最后按照优质储层物性界限,通过剪切模量、孔隙度和渗透率体得到优质储层三维表征体.上述方法在NBR油田A组油层中优质储层预测符合率达到78.3%,优选甜点区部署水平井效果显著.

Seismic prediction of high-quality reservoir is effective to support the producing reserves of low-efficiency well area and external expansion area in NBR oilfield,which is of great significance to improve oilfield productivity.To solve the problems of single parameter in post-stack inversion parameters and multiple solutions in pre-stack inversion,a three-step process is developed to realize pre-stack and post-stack joint inversion for the purpose of quantitative high-quality reservoirs characterization.Step 1 predicts the distribution of sandstone and mudstone by post-stack geostatistical inversion;Step 2 is the rock physical analysis,which shows that the shear modulus is the sensitive elastic parameter of oil-bearing sand body.Then,constrained by the results of Step 1,the pre-stack Extended Elastic Impedance(EEI)inversion is used to predict the oil-bearing property of the reservoir.Similarly,constrained by the results of Step 1,Step 3 uses Gaussian Collocation Co-simulation inversion for logging parameters to predict porosity and permeability.According to the boundary of physical properties in high-quality reservoir,the three-dimensional characterization of high-quality reservoirs is conducted by the shear modulus,porosity and permeability.In oil layer A the NBR oilfield,the coincidence percentage of the above method in predicting high quality reservoir reaches 78.3%,and the horizontal well deployment in preferred dessert area achieves a remarkable success.