Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination

Fluid discrimination plays an important role in reservoir exploration and development. At present, the fluid factors used for fluid discrimination are estimated by linear AVA inversion methods based on the linear approximations of the Zoeppritz equations. However, the Zoeppritz equations show that t...

Full description

Saved in:
Bibliographic Details
Main Authors: Lin Zhou, Xingye Liu, Tianchun Yang, Jianping Liao, Mingfeng Zhu, Gan Zhang
Format: Article
Language:English
Published: Wiley 2020-01-01
Series:Geofluids
Online Access:http://dx.doi.org/10.1155/2020/8860119
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849690385326014464
author Lin Zhou
Xingye Liu
Tianchun Yang
Jianping Liao
Mingfeng Zhu
Gan Zhang
author_facet Lin Zhou
Xingye Liu
Tianchun Yang
Jianping Liao
Mingfeng Zhu
Gan Zhang
author_sort Lin Zhou
collection DOAJ
description Fluid discrimination plays an important role in reservoir exploration and development. At present, the fluid factors used for fluid discrimination are estimated by linear AVA inversion methods based on the linear approximations of the Zoeppritz equations. However, the Zoeppritz equations show that the relationship between prestack AVA reflection coefficients and reservoir parameters is highly nonlinear. Therefore, inversion methods based on linear approximations will seriously influence the nonuniqueness and uncertainty of inversion results. In this paper, a nonlinear inversion based on the quadratic approximation is carried out to reduce the nonuniqueness and uncertainty of fluid factor. Firstly, in order to directly invert the fluid factor, a novel quadratic approximation in terms of the fluid factor (ρf), shear modulus, and density on both sides of the reflection interface is derived based on poroelasticity theory. Then, a nonlinear inversion objective function is constructed using the novel quadratic approximation in a Bayesian framework, and the Gauss-Newton method is adopted to minimize this objective function. The synthetic data example shows that the new method can obtain reasonable fluid factor inversion results even in low SNR (signal-to-noise ratio) case. Finally, the proposed method is also applied to field data which shows that it can effectively discriminate reservoir fluids.
format Article
id doaj-art-efa3b7518ff04e75aee9ccd8eaa4f7c6
institution DOAJ
issn 1468-8115
1468-8123
language English
publishDate 2020-01-01
publisher Wiley
record_format Article
series Geofluids
spelling doaj-art-efa3b7518ff04e75aee9ccd8eaa4f7c62025-08-20T03:21:19ZengWileyGeofluids1468-81151468-81232020-01-01202010.1155/2020/88601198860119Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid DiscriminationLin Zhou0Xingye Liu1Tianchun Yang2Jianping Liao3Mingfeng Zhu4Gan Zhang5Hunan Provincial Key Laboratory of Shale Gas Resource Utilization, Hunan University of Science and Technology, Xiangtan 411201, ChinaCollege of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, ChinaHunan Provincial Key Laboratory of Shale Gas Resource Utilization, Hunan University of Science and Technology, Xiangtan 411201, ChinaHunan Provincial Key Laboratory of Shale Gas Resource Utilization, Hunan University of Science and Technology, Xiangtan 411201, ChinaPetroChina Pipeline Compressor-Set Maintenance, Repair&Overhaul Center, Langfang 065000, ChinaSichuan Water Resources and Hydroelectric Investigation & Design Institute, Chengdu 610072, ChinaFluid discrimination plays an important role in reservoir exploration and development. At present, the fluid factors used for fluid discrimination are estimated by linear AVA inversion methods based on the linear approximations of the Zoeppritz equations. However, the Zoeppritz equations show that the relationship between prestack AVA reflection coefficients and reservoir parameters is highly nonlinear. Therefore, inversion methods based on linear approximations will seriously influence the nonuniqueness and uncertainty of inversion results. In this paper, a nonlinear inversion based on the quadratic approximation is carried out to reduce the nonuniqueness and uncertainty of fluid factor. Firstly, in order to directly invert the fluid factor, a novel quadratic approximation in terms of the fluid factor (ρf), shear modulus, and density on both sides of the reflection interface is derived based on poroelasticity theory. Then, a nonlinear inversion objective function is constructed using the novel quadratic approximation in a Bayesian framework, and the Gauss-Newton method is adopted to minimize this objective function. The synthetic data example shows that the new method can obtain reasonable fluid factor inversion results even in low SNR (signal-to-noise ratio) case. Finally, the proposed method is also applied to field data which shows that it can effectively discriminate reservoir fluids.http://dx.doi.org/10.1155/2020/8860119
spellingShingle Lin Zhou
Xingye Liu
Tianchun Yang
Jianping Liao
Mingfeng Zhu
Gan Zhang
Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
Geofluids
title Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
title_full Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
title_fullStr Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
title_full_unstemmed Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
title_short Nonlinear AVA Inversion Based on a Novel Quadratic Approximation for Fluid Discrimination
title_sort nonlinear ava inversion based on a novel quadratic approximation for fluid discrimination
url http://dx.doi.org/10.1155/2020/8860119
work_keys_str_mv AT linzhou nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination
AT xingyeliu nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination
AT tianchunyang nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination
AT jianpingliao nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination
AT mingfengzhu nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination
AT ganzhang nonlinearavainversionbasedonanovelquadraticapproximationforfluiddiscrimination