Analysis Of Factors Causing OOIP Variation In Raoyang Sag

The Reported proved oil reserves of the study area vary unavoidably at different time resulting from various standards,available data,original data collecting and the analysis and understanding level as well.Therefore,the proved oil/gas reserve recalculation of the study area is necessary for analysis of the factors causing reserve variation.By conducting such recalculation,further static and dynamic data of the oil field can be obtained,which can provide reserve data for development of the oil filed in the study area and also has guiding sense to the reserve study of other sags.This study is to carry out analysis on parameters which can influence reserves by calculation methods of the geological reserves.We focus on oil-bearing area and effective thickness to make analysis how they cause the variation in geological reserves by method of quantification and comparison.By comparing the reserve parameters pre and post recalculation of the block in Rao Yang Sag whose proved reserves vary during reservoir evaluation stage,we analyze how each parameter influences the reserve variation and then to ascertain the main influencing parameters and to finally make certain the factors causing parameter variation and the reserve variation.Moreover,we applied such method to other typical reservoirs in the study area,analyzing the main factor causing variation in reserve calculation during reservoir evaluation stage.It is concluded from study that the quality of seismic data affects the structural interpretation precision and cause parameter changes of oil-bearing area in reserve calculation,leading to significant deviation of the calculation results;the degree of well-control is also an important indicator of that whether the reserve calculation results of oil and gas reservoir is reliable or not;the cognition of reservoir features can also make calculation mistakes which is apt to happen in evaluation stages.Meanwhile,the amount of basic data can also impact the calculation precision of geologic reserves.