| The Linnan Xia52block, located in Linnan hollow Xiakou fault zone, is a fault block layered reservoir. It grows in the downthrown side of the fault, is a flat nose structure controlled by Xiakou large fault. The structure was cut into two fault blocks by NO.1Shuangfeng fault, the southwest of Xia52fault block, northeast of Xia32fault block. This block has90wells,11wells put into operation. According to the Xia52block upper Es3to down Es2reservoir formation lithologistic, electrical, physical properties, coring, cutting logging, analysis of laboratory data and previous stratigraphic division and correlation of research results, single sand body distribution law analysis as the key to the logging data shall prevail, the Xia52block upper Es3to down Es211wells and81wear well divided into eight sand and48small layers. According to the status of reservoir development, upper Es2to down Es3reservoir began to enter the period of rapid decline from1996, annual oil production dropped to2.74×104t, water cut rising to85%by1997, entering to high water cut stage. Therefore, it is necessary to establish the diminishing analysis law. The results of the analysis:the diminishing law of the reservoir meets the exponential decrease law, with diminishing rate of-0.075tmon-1.The number of wells in this block is small, but the number of small layers is big, sand containing oil is numerousa but scattered, and the sand body connectivity is poor, resulting in a complex distribution of remaining oil. The oil layer is mainly made up of fluvial facies, although the vertical and horizontal reservoir changes, it has such characteristics of good physical properties, light oil density, high permeability, and high-yield. Therefore, this block has great exploration potential. So, figuring out the remaining oil distribution and range are the main objectives of this study. Based on reservoir characteristics of this block, reservoir description,3-D geological modeling, and reservoir numerical simulation methods are used to illustrate the distribution of the remaining oil.1. The modeling process and research results.The modeling uses the principle of multi-disciplinary integration, based on scientific geological theory and the theory of three-dimensional geological modeling, make full use of all kinds of raw data (drilling, logging and geological data), based on geological, logging comprehensive interpretation and other research results, applying the advanced3D visual modeling software-Petrel2009software, established the Xia52fault block three-dimensional fine geological models, including the model of the three-dimensional structure, property model (porosity, permeability, saturation model), calculation of reserves. The range of the analog areas is:Xia52block Es2proven oil reserves of87×104t, laminated bearing area1.3km2; the Xia52upper Es3proven oil reserves and74×104t, laminated bearing area of1.0km2; Xia52total calculation of proven oil reserves of161×104t, the laminated oil-bearing area of1.5km2. In order to better characterize the fault, the corner grid plane grid was used, spacing to10×10, a total of229×188nodes. Dividing longitudinally emulation layer, each reservoir was treated as an emulation layer, longitudinally divided into a total of48layers.The reserve estimate was based on geological model, but to facilitate the use of numerical reservoir simulation, estimate the value of development and utilization of geological reserves. On the geological model for the reserves calculated on the basis of unit grid unit, followed by statistical reserve parameters of the layers of the grid unit, unit volume basis. Using Petrel software calculating Xia52block upper Es3to lower Es2reservoir model addresses reserves of160million tons, with relative error of-0.6%, compared to161tons of geological reserves. So the Xia52fault block upper Es3to lower Es2reservoir three-dimensional geological model is valid, it can be put into practical use.2. Numerical reservoir simulation and remaining oil distribution.In order to make further study of the reservoir underground oil, water dynamic relationship, understand the existing forms of movable oil, and make clear of the future development direction of the adjustment, numerical simulation method was used to make research of the Xia52block. The research work consisted primarily of numerical simulation model establishment and selection, production history matching and analysis of situation of remaining oil and tapping the potential of the program preferred. According to the past years dynamic production data, the simulation work used the three-dimensional three-phase black oil model. Of gridding, Xia52fault block was divided into longitudinal151Analog layers. On plane, upper Es3to lower Es2X direction of the sand reservoir54grids,35grids in the Y direction, can basically reflect the variation of reservoir properties and fluid movement. On the basis of coarsening geological model, numerical reservoir simulation research was carried out, with reservoir overall history matching, single well fitting80%.The remaining oil distribution of Xia52fault block upper Es3to Es2is more fragmented, the block plane injection and imperfect layer, the obvious contradiction between the plane and taking the current production situation into account, three sets of adjustment programs were designed to provide the basis for the next step to tapping the potential adjustment. Firstly, optimization of single well production allocation, compare well group control and single well control scheme, single well control program development is better; Secondly, extract program was carried out, when mining solution to2times faster, development effect of the extract is not good, the block extract was not recommended; Thirdly, deploying new wells program, in sand body with isolated remaining oil distribution, it is recommended to drill the adjustment well. |
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