Estimation of Original Oil in Place for Belhedan Oil Field by Using Volumetric Method, Material Balance Equation Method, and Reservoir Simulation Method

Abstract

Knowing the amount of the hydrocarbon pore volume correctly is basically required to have properly design of oil and gas reservoirs. The accuracy in calculating of the hydrocarbon pore volume depends on the used method. Usually two conventional methods use to estimate the Original Oil In Place (OOIP) very quickly. These two methods are volumetric method and Material-Balance-Equation (MBE) method. However, there is another quick method that can be used to calculate (OOIP) which is reservoir simulation method. In this paper, three difference methods were used to calculate OOIP to provide Waha Oil Company with the calculated value. Moreover, each method required sort of data; the volumetric method depends on static data. However MBE and reservoir simulation method require dynamic data of the reservoir and the area around. Usually the driving mechanism is the key point when MBE and reservoir simulation are used. The drive mechanism in studied area (Belhedan oil field) is described from the field information as a strong water drive with small gas-cap. The given field data don’t have any information about the gas cap and the water dive. As a result, applying the MBE method to calculate OOIP for this case require some information about the gas cap and the aquifer. So the MBE gave a value of OOIP didn’t agree with the value of OOIP that obtained from the volumetric and reservoir simulation. Lack in the information makes MBE unusable method in this case. It has been trying to solve this problem by use some correlation in calculate some parameters and ignore others. However, doing all that, the result couldn’t reach any closed value that is calculated by volumetric and reservoir simulation which will explain. In the end of the paper, a prediction of well performance (well v-4) will be done from 1970 until 2020.