The Well Logging Evaluation Study Of Water Flooded Layer In The A Oilfield

With the deeper development of oilfield exploitation,most oil fields in our country have entered into the middle-high water out stage.After oil layer being water flooded,the lithology,physical property,oiliness and electrical parameters will change,and the well logging response characteristics will become complex and changeful,which make it difficult to accurately evaluate the water flooded layer.From the research of the Y water flooded layer in A oilfield in the Western South China Sea area,this paper has achieved a set of method system for the effective evaluation of the water flooded layer,providing technical support for development adjustment of the block.At first,this paper comprehensively studied the general geological situation of the research block,including the geological structure,sedimentary characteristics and reservoir distribution forms,and researched the reservoir characteristics in depth.On the basis of the studies above,four-property relationship research of the reservoir was carried out,which lays the foundation for the comprehensive interpretation of water flooded layer.Then the physical property lower limit of the effective reservoir was comprehensively estimated by the following methods including porosity and permeability cross plot,irreducible water film thickness method,tail flick test and the minimum flow pore throat radius method.The well logging response characteristics before and after oil layer being water flooding were researched,also the well logging-logging comprehensive recognition method,carbon oxygen ratio logging cross plot and conventional logs blocks method were used to identify water flooded layer.Then the log interpretation models taking advantage of reservoir characteristic parameters were established after the depth collection of the core samples.Based on using the Archie formula,XiMenDu formula and Indonesia formula for estimating the water saturation,the material balance method was applied to optimal evaluation dynamically for remaining oil saturation.It was found that the Indonesia formula is the most accurate at calculating water saturation by contrast.At the end,the calculation model of water production rate and a water level division standard were established.Applying the research results above,the logging data processing and comprehensive interpretation were carried out in the wells of the study area and the accuracy achieved 85%,which has important guiding significance and promotion value for the block adjustment development.