Hydrocarbon reservoir testing

#1. Field of the Invention

#The invention relates to well testing of hydrocarbon reservoirs to determine economic viability.

#The purpose of reservoir simulation is to determine as precisely as possible the extent (volume), nature, permeability, and porosity of the payrock.

#The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:

#FIG. 1 is a high-level diagram showing a testing rig and a payrock;

#FIG. 2 is a more detailed diagram showing a wellbore and its penetration into the payrock;

#Referring to FIG. 1, the overall context for reservoir testing is illustrated. A testing rig 1 is erected over a payrock 2 containing a reservoir of a hydrocarbon (oil or gas). A wellbore 3 is drilled at an angle into the payrock, and alternative angles 4 and 5 are shown.

#As shown in FIG. 2, the part of the payrock 2 surrounding the wellbore 3 is referred to as a damaged zone 10. Oil flows through the damaged zone 10 and the lining perforations into the wellbore 3 under the reservoir pressure. A valve 11 controls flow from the top of the wellbore 3 to a stock tank 12. A fault line 13 at one end of the payrock 2 is also illustrated in this diagram. Flow from the wellbore 3 to the stock tank 12 is denoted qv(t) and wellbore storage is denoted cVst. Various pressure sensors (not shown) are mounted within the wellbore 3 so that an actual pressure change (or curve) as a function of time can be measured.

#Referring now to FIGS. 3, 4(a), and 4(b) a method 20 for reservoir testing and analysis is described. In a step 21 oil flow is measured using the pressure sensors. This step also involves laboratory analysis of oil samples drawn from the stock tank 12.