SPE-193681-MS
Hydraulic Dilation Stimulation to Improve Steam Injectivity and
Conformance in Thermal Heavy Oil Production
Yanguang Yuan
, BitCan Geosciences & Engineering Inc., Calgary, Canada
Summary
In thermal heavy-oil production, steam is injected to reduce oil viscosity and promote the less viscous oil
flowing to the production wells. Steam injectivity and its conformance in the reservoir greatly impacts oil
production and project economics. It is found that hydraulic dilation stimulation of heavy-oil reservoirs
before steam injection can create a large and targeted stimulated reservoir volume for the steam to contact the
heavy-oil phase. As a result, steam injectivity increases and steam conformance improves. These eventually
translate to increased oil production and reduced steam/oil ratio, which has been proven in hundreds of
wells worldwide. This paper describes relevant fundamental mechanisms and field performance.
As a major novelty, the hydraulic stimulation avoids fracturing the reservoir, but seeks to cause dilation.
If the reservoir is fractured, a linear conduit is created. Steam can easily break through to neighbouring wells
and the steam conformance is poor. When dilation takes place, however, additional pore space is created in
the rock matrix. This results in truly volumetric stimulation, which is helpful to increase the steam injectivity
while ideal thermal conformance is also achieved. This paper illustrates these theoretical bases and their
resultant positive field performance in assisting thermal heavy-oil production.