Surface Subsidence InSAR Monitoring And Reservoir Parameter Inversion In Liaohe Oilfield

Oil,known as the "blood of industry",is a precious and non-renewable energy source and an indispensable resource for the development of human industrial civilization.In the process of oil exploitation,due to lack of understanding or mastery of reservoir state information in oilfield,over-exploitation or uneven exploitation lead to damage of reservoir geological structure,and then lead to underground reservoir compaction,which will not only reduce the effective recovery rate of oilfield,but also cause large-scale and large-gradient surface subsidence.With the help of geophysical inversion method,inversion of reservoir parameters through surface deformation and timely grasp of reservoir state changes are of great practical significance for the formulation of oil production plan,the evaluation of oilfield stability and the sustainable development of oil production.However,in the existing research on inversion of reservoir parameters by surface deformation,there are some problems,such as limited spatial resolution of deformation field data,inadequate adaptability of inversion model and lack of quality evaluation of inversion results.These problems have caused serious constraints on the inversion of reservoir parameters,and need to carry out targeted theoretical and technical research.Aiming at the above problems,this paper takes Liaohe Oilfield,the third largest oilfield in China,as the research object,and carries out the inversion research of reservoir parameters.In order to provide detailed and accurate surface deformation information for reservoir parameter inversion,21 PALSAR data from January 2007 to September 2010 and 22 Sentinel-1B data from December 2016 to December 2018 were used to monitor surface subsidence in Panjin area of Liaohe,where oil wells are widely distributed.The results show that:(1)During the two monitoring periods,there are two distinct subsidence funnels in Panjin area of Liaohe,which correspond to Shuguang Oil Production Plant and Huanxiling Oil Production Plant of Liaohe Oilfield respectively.(2)For areas with large gradient subsidence and more vegetation coverage,StaMPS technology has stable and reliable subsidence monitoring ability,and PALSAR data in L-band has stronger anti-jamming and detection ability than Sentinel-1B data in C-band.Shuguang Oil Production Plant is the largest oil production plant in Liaohe Oilfield,and is a typical area of land subsidence caused by oil exploitation.Therefore,this paper takes Shuguang Oil Production Plant as the research object,introduces the non-linear Bayesian inversion algorithm of stochastic inversion method into reservoir parameter inversion for the first time,takes InSAR deformation results as observation variables,uses Mogi model,Finite Prolate Spheroidal model and Okada model to invert reservoir parameters respectively.During the experiment,more than one deformation source in the underground of Shuguang Oil Production Plant was found.In this paper,the double-source model was introduced into reservoir parameter inversion for the first time.The results show that:(1)Non-linear Bayesian inversion algorithm can not only get the optimal value of model parameters,but also evaluate the uncertainty of inversion results.(2)When using single-source model to invert reservoir parameters,the inversion results of Okada model are the best,the inversion results of Finite Prolate Spheroidal model is better,and the inversion results of Mogi model is worst.(3)The inversion results of double-source model are better than those of single-source model.(4)When using double-source model to invert reservoir parameters,the inversion results of double Okada model are the best,the inversion results of Finite Prolate Spheroidal and Okada combination model are better,the inversion results of double Finite Prolate Spheroidal model are worse,and the inversion results of double Mogi model are the worst.The study of inversion of reservoir parameters by surface deformation in this paper will provide important theoretical reference for inversion of reservoir parameters in other oilfields at home and abroad,and has important practical significance for reasonable exploitation of oil resources and evaluation of oilfield stability.