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Study On The Fracture-cave Carbonate Reservoir Model And The Prediction Technique Of Tahe Oilfield

Posted on:2009-05-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z J LiFull Text:PDF
GTID:1100360242993048Subject:Paleontology and stratigraphy
Abstract/Summary:PDF Full Text Request
The fracture-cave carbonate reservoir of Tahe oilfield is different from the fractured carbonate reservoir and reef-pore reservoir, and even more different from the conventional porous sandstone. It is a kind of complex geological body, which has undergone multi-stage tectonic disruption and paleo-weathering karstification, with strong heterogeneity on both vertical and horizontal direction. Since no effective technique series is available at present, the prediction for its spatial distribution is still a worldwide problem and a frontier topic in hydrocarbon exploration and development field.By using the seismic, geologic and logging data, this paper tries to probe the technique and method for the study of fracture-cave carbonate reservoir" model and prediction, and has obtained the following achievements.The fracture-cave carbonate reservoir of Tahe oilfield is mainly controlled by paleokarst, structure and rifting, with Caledonian and Hercynian karstification dominantly developed. The sedimentary facies of middle-lower Ordovician in Tahe oilfield is dominantly open platform, with intraplatform point reef sub-facies developed in Yijianfang formation. The development of fracture-cave reservoir in middle-lower Ordovician is not obviously controlled by the sedimentary facies type.The mathematical and physical simulation of fracture-cave reservoir with different shapes, sizes and characteristics has been carried out, and the seismic wave field feature was systematically studied. Then this paper established the relationship between seismic reflection energy and spatial sampling rate of karst cave for the first time, and summarized the seismic response feature of fracture-cave carbonate reservoir. This laid the theoretical and experimental foundation of reservoir prediction technique and method.The derivative concept of gravity and magnetic potential field data processing was introduced to seismic property study, and the technique of seismic amplitude variation rate was creatively put forward. It overcame the effect from the lithology variation overlying fracture-cave reservoir which may influence the absolute value of amplitude, and has become to be the principle technique for fracture-cave carbonate reservoir prediction.The trend surface analyzing method was introduced in the karst fracture-cave reservoir prediction, and the difference analyzing technique of trend surface was put forward for the first time. The result shows that the distribution of monadnock and fold at the top of middle-lower Ordovician in Tahe oilfield can control the generation of fracture-cave carbonate reservoir.The integrated technique and method series for fracture-cave carbonate reservoir prediction was constructed, including exquisite imaging, seismic amplitude variation rate, seismic reflection feature, exquisite coherent data of eigenvalue, trend surface difference analysis, waveform analysis, 3D visualization, seislog joint inversion.Wellsite optimum seeking technique was determined to include amplitude variation rate that dominated by seismic reflection feature analysis, trend surface difference analysis, eigenvalue exquisite coherent data and multiple parameters. This provided technique support for wellsite optimum deployment.By using the above-mentioned technique, favorable reservoir belt was predicted, and Aidingbei-Yuqixi area, Tuofutai, and Yuqidong area were chosen as the favorable target zone. The identical ratio for reservoir prediction of exploration and development wells is above 90%.
Keywords/Search Tags:Tahe oilfield, fracture-cave carbonate reservoir, forward modeling, reservoir prediction, amplitude variation rate trend surface
PDF Full Text Request
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