The KK Oil Field Fine Geologic Modeling Research

Entering90’s of20th century, with the development of reservoir description to quantitative modeling and accurate prediction of the direction, therefore, we must adopt a series of quantitative research methods, more accurate description of the underground reservoir spatial distribution and heterogeneity of reservoir characteristics to establish a precise quantitative reservoir models[1].In recent years, more and more scholars recognized the sedimentary microfacies that have control function to porosity and permeability of reservoir parameter. The reservoir is deterministic, but it is one of the many complex processes (such as sedimentation, denudation, into the rock structure and function change and so on) as the result of the comprehensive action[2].Random modeling is based on geological statistics as the foundation, core analysis, logging interpretation, seismic exploration results, dynamic production data and outcrop and other data, according to the geological characteristics and the statistical regularities of sedimentary facies unit, flow unit, reservoir parameter simulated distribution, which form the eventual establishment of a stochastic model[3].3D reservoir modeling is the angle from three-dimensional quantitative research of reservoir, which focuse on pair of reservoir comprehensive multidisciplinary integration, three-dimensional quantification and visualization prediction[4].3D reservoir model overcomes the two-dimensional map description of3D reservoir limitations and can be obtained from the three-dimensional quantitative characterization of reservoir heterogeneity[5]. In addition,3D geological model simulation results can be directly compared with three-dimensional numerical reservoir simulation software standards, which is advantageous to the integration study of Geology and reservoir numerical simulation[6].With the increasingly widespread application of geological statistics, basic theoretical research in more depth, geological statistics research tool variogram development different variogram model such as the common semi variogram function (Semivariogram), cross variogram (Cross Semivariogram), common relative difference function (General relative semivariogram), opposed pairs variation function (Pairwise relative semivariogram), the logarithmic variation function (Semivariogram of logarithms), the absolute value of the variogram function (Semimadoram), indicating the variogram function (Indicator semivariogram)[7]Geostatistics core, Kerrey gold method obtained the considerable development. In addition to the current commonly used simple Kerrey method, general Kerrey and the Kerrey method, still appeared to assist Kerrey (Cokriging), directed by Kerrey lattice (Indicator Kriging), parity (Colocated Kriging), Kerrey Kerrey (Fuzzy Kriging fuzzy lattice method), Kerrey King (Kriging with a trend, Trend) probability of the Kerrey gold (Probability Kriging), Kerrey King (Factorial Kriging) factor, indicating the principal component Kerrey (Indicator principle component Kriging), a drift of the Kerrey gold (Kriging with an External Drift), nonlinear Kerrey gold (Nonlinear Kriging) and so on [7].These methods are designed accoring to different sources of information, accuracy and characteristics. It provides extensive ways to solve problems of the reservoir parameter analysis and forecasting. Variation function is the basic geostatistics tools. Kerrey interpolation and stochastic simulation of the algorithm based on image element most need the variogram function. Variation function to characterize the regionalized variable spatial variation characteristics, especially through random representing regionalized variable spatial structure. Variation function study mainly includes experimental variogram calculation, theoretical variogram fitting and the variation function of geological interpretation.In the perspective of the major terms, Random simulation method can be divided into two categories:continuous and discrete. Continuous simulation is used to describe the geological phenomena and characteristics of the continuous change. Such as the description of reservoir physical parameter field, velocity field, commonly used methods of Gauss simulation, simulated annealing simulation, fractal simulation. Discrete type commonly used to describe with the discrete nature of the geological characteristics. As described in the spatial distribution of sand body, fault distribution, facies distribution, common method is Boolean simulation, indicative simulation, point process simulation and so on.These aspects in petroleum geology has many successful applications, and from the published literature, which can be used from static to dynamic reservoir characterization study of the whole process, wraparoundly basically solving the following problems:①Simulate various facies, sedimentary facies distribution and the relationship between different facies belt②Simulate fault (band), the spatial distribution of fracture (band), direction, length③Simulate Md, K and other physical properties and lithology parameter spatial distribution④Simulate sand body connectivity, shielding layer of the spatial variation of⑤Calculate reserves, yield forecast simulation⑥Exploitateoilfield development, the risk evaluation modelK-K oilfield in structure is located on Niger delta basin extensional tectonic belt" roof structure and back-to-back fracture zone", and the overall shape is complicated by faults anticline anticline axis, axial near east-west, two basic symmetry, shallow faults, antiform incomplete, deep fault, anticline morphological integrity.The K-K oilfield mains on the delta front subfacies of underwater distributary channel, mouth bar, barrier deposition, part of the developmental lagoon, delta front subfacies. The whole belongs to high porosity and high permeability reservoirs. At present the data of18wells,12wells drilled formation, there are23small oil,38oil sand body. Vertical strata, wide distribution, B, C, D, F, G and H sand group were drilled reservoir, reservoir buried depth of1578-3584meters, mainly in the B-D sand group, depth of1578-2600M. Proven geological reserves is136.37MMbbl prediction reserves is50.13MMbbl, and they has considerable value of mining.In view of the poor quality of the seismic data and the lack of VSP seismic logging data, they brings difficulty to fault identification, implement, implement structural trap, the fine description of fault zone, and affect the structure and trap the degree of implementation. We need to carry out reservoir geological modeling, meanwhile to impleme a variety of traps and fault, to provide accurate static data for the reservoir numerical simulation.This paper takes the KK oilfield for example, carrying out for the complex fault block reservoir geological modeling study. Through the research projects, we achieved the following results:1Further confirmation of the fault geometry form and the relationship between the fault, through the well of the combination of the shock of faults with the way; Through the seismic data of tectonic level the constraints of the correction.2Fine established OML66block KK oil field complex fault block of tectonic model, especially the fault of complex in contact with the model are very good expression.3Application of multidisciplinary integration, such as phase control modeling, using PETREL2005was established for the study area B to G three-dimensional sedimentary facies model and3D reservoir parameter model (including porosity, permeability, oil saturation and NTG model), the model can objectively reflect the reservoir3D distribution, especially oil saturation can be set up to fine embodiment of toothbrush shape to reservoir with edge and bottom water reservoir properties and morphology.4In fine geological model based on B to G, calculation of sand group and different blocks of different reservoir reserves, reserves of geology of anastomosis with relatively high degree.5Through the reserves uncertainty analysis, the fault block, each layer of most probable reserves distribution, as the next step in the development of programs to provide reliable basis.6To model fault block points the coarsening, established12sets of coarsening of three dimensional NTG model, porosity model, oil saturation model, and the output format by ECLIPSE.