The Research Of Fracture Description And Reservoir Simulation Of C Reservoir In Putumayo Basin

The C reservoir of the Putumayo Basin, located in the southeast part of Columbia, is loose pebbled sandstone fractured heavy oil reservoir with oil gravity around 9.5oAPI. The production of this reservoir started in Nov. 2011, using vertical well, horizontal well and steam huff and puff to test the productivity. The deliverability of individual well varies significantly because of the heterogeneity of fractures and the current recovery factor is only 0.2%. The present study aims to develop this reservoir economically and effectively by systematic reservoir description and numeric simulation.There are many geologic factors which can affect the growth of fractures, and the interaction among these factors makes the description of fracture distribution a big challenage. The literature about fracture prediction, fractured reservoir modeling, fracture reservoir numeric simulation and other development technologies has been thoroughly reviewed and integrated with image logging, seismic curvature property, well test and mud loss data to analyze the distribution patterens of fractures in the present study.The relationship between fracture density and seismic curvature has been established and the distribution of the fracture density has been predicted on the basis of geological model of the fracture and matrix. Reservoir simulation has been applied for fluid property and production performance analysis. Coupled with conventional reservoir engineering resarch, the development method, well type, well pattern and steam injection parameters of C reservoir can be optimized. The innovative results of the present study can be highlighed as follows:1. Ranning high precision scanning for the seismic event with a global optimization scanning algorithm to get the high precision seismic curvature property. Multiscale seismic curvature property can be successfully applied to predict the fracture of C reservoir qualitatively. The curvature property is strongly correlated with the fractured zone and the curvature distribution is strongly correlated with the fracture orientation.2. Using the radial basis function neural network(RBF) technology in the fracture density inversion proceeding, coupled with geostatistics, to implement the inversion with multi property driving on the base of geostatistics. Therefore, not only stable inversion result can be obtained, but also the nonlinear constraint of seismic multi property to the inversion result can be illustrtated.3. Optimizing development parameters on the base of cold production and steam huff and puff theory to designe 4 cold production cases. Some wells were chosen to shift from cold production to steam huff and puff at a suitable time in the optimized case. Five existing wells were reused, 22 new horizontal wells were drilled and 15 wells among them were changed to steam huff and puff at a suitable time. After all these measure, the recovery factor of 12.8% and the watercut of 96.6% can be projected at the end of the contract.The present study takes the most advanced reservoir simulation theory as the foundation and large quantity data as the supporter. The results can not only be successfully applied in the production practice of the studied area but also be used as a reference for research and development of the similar reservoirs.