Heavy oil is classified as unconventional oil resource because of its difficulty to recover in its natural state, difficulties in transport and difficulties in marketing it. Upgrading solution to the heavy oil has positive impact technically and economically specially when it will be a competitive with conventional oils from the marketing prospective. Developing Qaiyarah heavy oil field was neglected in the last five decades, the main reason was due to the low quality of the crude oil resulted in the high viscosity and density of the crude oil in the field which was and still a major challenge putting them on the major stream line of production in Iraq. The low quality of the crude properties led to lower oil prices in the global markets as well as the high operation cost of production and transportation. The purpose of this paper is testing new technology applications on an Iraqi Heavy Oil Field and specifically (Qaiyarah Oil Field) by applying the cold cracking technique to upgrade Qaiyarah heavy oil properties through using series of electrical/ mechanical activities applied on the heavy crude that generates special kind of vibrations to re-structure the (H-C) bonds in the heavy oil to convert it to lighter crude with lower viscosity/ density which was the outcome of the distillation by reducing the unsaturated components and isolating the minerals and sulfur as sold components. The results were very optimistic, where the density has improved from 16 to 30.5 API degree, sulfur content has reduced from 6.4 to 1.507 weight percent and selling price per barrel would increase by 53% compare to 2.31% cost increment due to the upgrading operation. Therefore, applying the cold cracking technology is convenience for improving Qaiyarah oil properties as the main production stream line will be increased in Iraq.
Most of the productive oil fields around the world are water drive reservoirs where water influx has the potential to improve oil recovery considerably. Verifications are required to illustrate the aquifer activation and this needs assessment programs to include diagnosis, classifications and aquifer characterization using mathematical models for accurate simulation of the aquifer behavior. In Qaiyarah Oil Field, there is a big lack in subsurface data to confirm the aquifer's level of activity although there are some traces of water production from the wells located at the southwest of the field. Based on this fact, a base case simulation has run through making history match for the production and reservoir pressure to confirm the activation of the aquifer. The results showed a fast decline in the reservoir pressure which mismatched the current measured pressure from the field. This led to adopt the option of modelling a simulated properties aquifer to match the production and pressure from the field in a step to confirm the aquifer activation. The simulation had re-run with multi trials to approve the aquifer strength, geological and reservoir properties. Finally, history match showed perfect matching on production and pressure through selecting edge aquifer model that matched with the available subsurface data from the field. The cumulative production till the end of 2021 was calculated to be 47,142,257 bbls and reservoir pressure was 387 Psi, which almost match the measured cumulative production from the field that was 47,100,000 bbls and reservoir pressure of 389 Psi which was considered a very acceptable match.
Visualization of subsurface geology is mainly considered as the framework of the required structure to provide distribution of petrophysical properties. The geological model helps to understand the behavior of the fluid flow in the porous media that is affected by heterogeneity of the reservoir and helps in calculating the initial oil in place as well as selecting accurate new well location. In this study, a geological model is built for Qaiyarah field, tertiary reservoir, relying on well data from 48 wells, including the location of wells, formation tops and contour map. The structural model is constructed for the tertiary reservoir, which is an asymmetrical anticline consisting of two domes separated by a saddle. It is found that the three formations in the tertiary reservoir is composed of limestone and dolomitic limestone with very thin shale rims introduced only in the Dhiban Formation, which have the minimum thickness compared to the main other two formations those considered the main reservoir units. Upscaling from the software has been used to distribute and correlate between the logs and core data, which came very acceptable results to be used for distribution to the entire field. Both log analysis and core data have showed that the reservoir is clean formation, no volume of shale has considered in the STIIOP calculations with average water saturation calculated to be 31.5% and average porosity of approximately 22% with temperature gradient of 1.2 °F/100 ft. This comes up with Stock Tank Initial Oil in Place calculated to be 6.519*109.
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