EVALUATION AND ANALYSIS OF RESERVOIR FLUID FLOW EFFECT ON FIELD STRESS; A NEW APPROACH TO ALLEVIATE INDUCED SEISMICITY IN HYDROCARBON RESERVOIRS

Annually, natural and artificial earthquakes cause irreparable damages for human communities. Induced seismicity which refers to human-made shocks and tremors that alters the stresses state on the Earth's crust, invigorates in form of hydrocarbon reservoir-induced seismic that is related to operations with changing reservoir stress states. As it is provided in many references and research projects, reservoir stress field is a strong function of reservoir pore pressure. Hence long term production and injection scenarios or stimulation activities influence the stress state of reservoir based on time and place in the reservoir span.

Among all indicated parameters including long term production-injection operations, stimulation, and reservoir pressure variations in time and place, there is another key parameter named fluid flow rate which could be controlled by us to calm down stress disruption and thus alleviate induced seismicity magnitude in hydrocarbon reservoirs. During reservoir stimulation, long term production- injection, the only parameter which is altered dramatically and caused some hazards is the fluid flow rate in the well and all situations in reservoir. Reservoir pressure is a strong function of fluid flow rate and thus filed stress could be formulized based on that in reservoir as well.

In this approach using diffusivity equation in reservoir space and solving it with analytical and numerical methods, reservoir pressure is related to fluid flow in all distance from the producing well to reservoir boundary for all times steps. Accordingly, reservoir stress state could be formulated based on production flow rates. During single or multi wall production, sensitive locations around the flowing wells have the biggest chance for induced seismicity. Regarding that flow rate is the only attainable tool in order to control the intensity of stress confliction, this method proves numerically "How much dividing the producing fluid flow into several ways will lessen the chance of stress confliction and induced seismicity in Hydrocarbon Reservoir Spaces".

The accuracy of this method is confirmed using production data and numerical models of two giant hydrocarbon fields located in western section of Persian Gulf, Southern Iran.