Exploration Technology Practice of Thin Sand Lithological Reservoirs: Taking K Area in Oriente Foreland Basin, South America as an Example

Taking the Cretaceous M1 reservoirs of the K oilfield in the Oriente Foreland Basin of South America as an example, this paper focuses on the comprehensive geophysical prediction method of marine thin reservoir in order to achieve accurate identification of thin reservoir lithological traps, aiming at the difficulties of thin reservoir, rapid lateral change and difficult identification of rolling external expansion traps encountered in the rolling exploration of this mature basin. The specific technologies include: Using seismic forward modeling, setting up various geological models of reservoir morphology and surrounding rock physical properties, establishing reflection characteristics of different models by wave equation, and optimizing reservoir geological models based on actual seismic facies; Using amplitude seismic multi-attributes method, defining effective nonlinear relationship between logging information and seismic attributes, so as to further realize the spatial distribution of reservoirs; Using the spatial expansion of basis function with definite geological and geophysical significance to predict the distribution trend of reservoir thickness, comparing and verifying the amplitude attributes prediction results. The lithological trap in the study area was accurately predicted by using this set of technical process, and the proposed K4 exploratory well drilled 14ft high quality pure oil reservoir and achieved high production. The rolling exploration made a great breakthrough seven years after the failure of the early exploratory well. This set of technical process also has guiding significance for exploration of other marine thin layer clastic lithological reservoirs.