Reservoir Architecture Characterization And 3D Geological Modeling In Nanpu 1-29 Area

Guantao Formation in Nanpu 1-29 Area of Jidong Oilfield is in the stage of high water cut and low recovery.The reservoir heterogeneity is extremely complex,the river type is unknown,the reservoir architecture analysis is lacking,and the remaining oil development adjustment is difficult.It’s urgent to carry out architecture analysis,build a3 D reservoir geological model,expose the main factors affecting the distribution of remaining oil,and provide a guidance for the next development of oil field.This thesis first divide the stratigraphic framework on the basis of previous research experience and structural characteristics,and then use sedimentary background,granularity characteristics,core characteristics,and sand body distribution to determine the river type,and believe it belongs to the wandering braided river deposit.It is found that there kinds of sedimentary microfacies are developed,namely,channel bar,braided channel and flood plain.Based on the analysis method of architecture elements,the reservoir architecture classification,architecture anatomy,quantitative characterization and sand body superposition style analysis of Nanpu 1-29 Area are completed,and establish the 3D structure model,sedimentary facies model and physical property model.The main research results are as follows.(1)According to the previous stratigraphic division experience,this thesis uses the marker layer method to find that the Ng IV(2)1 and Ng IV(2)2 in Nanpu 1-29 Area of Nanpu1 structure are mainly dark gray basaltic mudstone,partly mudstone and tuff,the thickness is about 15-25 m.The resistivity curve is characterized by low value,and the natural gamma curve is characterized by high value.It can be used as a regional marker layer in Nanpu 1-29 Area.Finally,it is divided into 8 small layers and 13 single sand layers in the study area.(2)In the study area,the climatic condition is dry,the slope is large,and it is easy to scour and silt.Core observation shows that the study area is dominated by medium-coarse sandstone,cross-bedding,erosion surface development,and muddy interlayers are rare,indicating that the channel bar of braided river is easily transformed,with poor stability and strong river swing.The probability curve of grain size is mostly steep two-stage type,which is mainly manifested as jumping population and suspension population,especially the jumping population,and the rolling population is not well developed,showing obvious low slope braided river.The tectonic activity led to the enhancement of denudation in the sediment source area and the increase of river energy,which created good conditions for the formation of alluvial fan and braided river system.Therefore,the low-slpoe wandering braided river deposition of the river type is determined by sedimentary environment,core characteristics,grain size characteristics and sand body distribution characteristics of the study area.(3)In this thesis,referring to the Miall’s architecture division scheme,the reservoir architecture level in the study area is divided into 5-3 levels by using the architecture element analysis method,which are single braided flow zone level,channel bar and braided channel level and mud interlayer level inside the channel bar,and the 5-3 level reservoir architecture level identification is the focus point,and the reservoir architecture anatomy and quantitative characterization of the study area are completed.The study found that there are three main types of sand body stacking patterns in Nanpu 1-29 Area,namely,channel bar-channel bar splicing type,channel-channel bar or channel bar-channel splicing type and channel-channel splicing type.In the study area,the length of a single braided flow zone is about 365.16-1349.72 m,the width is about 270.57-1160.54 m,the single channel bar’s length is about 158.89-318.32 m,the channel bar’s width is about 75.97-116.41 m,the braided channel’s width is about 16.81-180.05 m,and the length-width ratio of channel bar is concentrated between 2-4.(4)Based on the dynamic development data,the static distribution model and the dynamic response curve are compared and analyzed to verify the correctness of the reservoir architecture work and guide the subsequent development of the oilfield.(5)The sedimentary facies model of Guantao Formation in Nanpu 1-29 Area is established by using the method of 2D profile reconstruction and 3D geological model,based on the 13 planar sedimentary microfacies maps in the study area,4 sections in the direction I,4 sections in the direction J and 9 planes in the direction K are selected as training images.The physical property models including porosity model,permeability model and water saturation model are bulit by using the Sequential Gaussian modeling method with facies control as geological constraint,so as to help improve oil recovery and guide subsequent residual oil development.