Hydromechanical Behavior of Fault Zones in Petroleum Reservoirs

da Fontoura, S. A. B. (Pontifical Catholic University of Rio de Janeiro) | Inoue, N. (Pontifical Catholic University of Rio de Janeiro) | Righetto, G. L. (Pontifical Catholic University of Rio de Janeiro) | Lautenschläger, C. E. R. (Pontifical Catholic University of Rio de Janeiro)

OnePetro 

ABSTRACT: The presence of faults is expected to affect the flow of fluids through areas of the reservoir and to have an effect on the mechanical behavior of the reservoir itself. It is a known fact that hydrocarbon production and fluid injection into the earth crust may induce seismicity and undesired reservoir fluid leakage due to localized movements along faults. The behavior of a fault zone depends on the stresses acting upon it and the stresses do change during reservoir production. This paper discusses the mechanical and hydraulic properties of fault zones within petroleum reservoirs. Initially a discussion of fault zone architecture is presented and this architecture is the result of the rock failure process. It follows a discussion on the hydraulic properties of fault zones. Next, a review on the mechanical properties is presented describing how the properties can be estimated. In the end, we offer suggestions on how to couple the hydromechanical processes in order to evaluate the possibility of fault reactivation.

1 INTRODUCTION

1.1 Generalities

The presence of faults is expected to affect the flow of fluids through areas of the reservoir and to have an effect on the mechanical behavior of the reservoir itself. During hydrocarbon production, fluid withdrawal and injection may cause displacements and strains along the faults present in the reservoir that may be responsible for the loss in reservoir sealing and some minor earthquakes.

Seismicity associated with high pore pressures resulting from fluid injection at depth has been registered in several cases (Healy et al. 1968, Raleigh et al. 1976, Zoback & Haijes 1997). Donnelly (2009) reports on the mechanics of shallow depth fault reactivation associated with mining exploration and onshore fluid extraction activities. Large areas at surface may be affected, presenting evidences of subsidence and development of scarps.

Suckale (2010) presents data associated with induced seismicity around producing hydrocarbon fields and CO2 injection locations, associated with fault reactivation. Other examples do exist and certainly new cases will occur but the Groningen gas field, Sanz et al. (2015), is a good example of induced seismicity, caused by large hydrocarbon extraction that brought about the state government decision of reducing production in order to control the seismicity.

  Country: North America > United States (1.00)
  Industry: Energy > Oil & Gas > Upstream (1.00)
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