--> Abstract: Stochastic Inversion as a Tool for the Construction of Carbonate Reservoir Models, by A.S. Rabey, D.V. Klyazhnikov, E.O. Malysheva, N.N. Chernoglazova, and A.L. Korzun; #90072 (2007)

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Stochastic Inversion as a Tool for the Construction of Carbonate Reservoir Models

A.S. Rabey1, D.V. Klyazhnikov1, E.O. Malysheva1, N.N. Chernoglazova1, and A.L. Korzun2
1Fugro-Jason, Moscow, Russia
2Zarubezhneft, Moscow, Russia

The technologies of stochastic inversion were applied to carbonate reservoirs of several hydrocarbon fields in Timan-Pechora and Caspian basins. Worked out models proved to be very predictive in evaluating effective porosity of cavern-pore type reservoirs. However they revealed the problems with characterization of fractured and pore-fractured reservoir types.
The current work touches upon the problem of mutual characterization of carbonate reservoirs of several oil fields on the south of Khoreyver depression (Timan-Pechora basin, North-East European Russia) confined to Lower Silurian carbonates. The productive interval is composed of dolomites, limestones and brecciated rocks. The considered area was subjected to strong subaeral erosion in Middle to Upper Devonian time and faulting. As a result Lower Silurian carbonates display a great variety of secondary features including sinkholes, leaching and karstification.
To obtain reservoir properties distribution AVA stochastic inversion “RockMod” (Fugro-Jason technology) has been carried out. It integrated the results of elastic modeling which in turn incorporated the data on core lithology and petrophysical rock types. It has been found out that the best porosity and net thickness values were confined to secondary dolomites with cavern-pore porosity and were proved by two new wells. However the highest oil flow rates were reported not from the “best” reservoirs that could suggest the fractures influence. To evaluate and delineate the zones of possible fracture influence the relationships between the flow rates and some AVA parameters (near versus far angles amplitudes difference, etc) were used.
As a result of applied approach 3D carbonate reservoir model has been worked out. It provided the prognosis of lithology, porosity, net and net pay thicknesses, top and the base of reservoir intervals and some other parameters. Moreover the model was supplemented by tentative lateral distribution of fractured influenced reservoirs.

 

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece