Advances in Petroleum Exploration and Development

Enhancing the Effectiveness of Vertical Water Injection Wells With Inflow Control Devices (ICDs): Design, Simulation and Economics

S. E. Nnakaihe, U. I. Duru, N. P. Ohia, B. O. Obah B. O. Obah, F. N. Nwabia — Mon, 26 Jun 2017 00:00:00 +0000

Water injector completion techniques used traditionally, such as frac packs or openhole standalone screens, were judged to be incapable of meeting all completion objectives and have been reported to loose injectivity over time coupled with the issue of long term injection conformance due to plugging. Another major challenge is to achieve even distribution of the injected water into all zones along the wellbore. Permeability contrasts, formation damage, creation of thief fractures, and changes in wellbore injectivity need to be managed to avoid early breakthrough in adjacent production wells. This study presents the application of inflow control devices (ICDs), fined tuned by reservoir simulations for balancing the water injection profile into various sand formation zones in an open–hole completed injector well in Flo-Z6, a stratified Niger Delta reservoir with communicating layers.
The solution targeted at developing a screening tool for deciding candidate layers in Flo-Z6 reservoir and installing special flow control devices, tailor-made for injection wells and with correct nozzle sizes for this particular case.
The results from this study show that, the installation of ICDs with different nozzle configuration in the injector wells tailored to equalize the water outflow (for better sweep efficiency), improved the field oil recovery by 11.9% (6.6MMstb). Economic indicators used to validate the profitability of the investment further showed that completing the injectors with different ICD nozzle configuration was more profitable, with an NPV@10% of $192.5million, profit per dollar invested of $6.6, DCF-ROR of 81% and a pay-out period of 1.2 year which is relatively short.

Feasibility Study on Resonance Enhanced Drilling Technology

Haige WANG, Siqi LI, Guodong JI, Zhijian HU, Tie YAN, Lijie TAO — Mon, 26 Jun 2017 00:00:00 +0000

With the increasing of well depth, the hardness of rock increases which will lead to rock is difficult to be broken. Therefore, Resonance Enhanced Drilling as one of new efficient drilling technologies is presented to improve the efficiency of drilling. The paper is focused on the feasibility study on Resonance Enhanced Drilling, showing the results of the numerical analysis and presenting the implementation methods of the technology. Two kinds of numerical simulations are performed, including modal analysis and harmony analysis of rock and indenter. Also, the excitation frequency is optimized under the actual operation conditions to analyze whether Resonance Enhanced Drilling can be achieved.
Our investigations confirm that both rock and drill bit can be resonant, and there are different resonant frequencies and vibration modes in different orders which are only related to their inherent characteristics. In addition, when the rock drilled is resonant and easily broken, the drill bit will not be destroyed. As a result, the Resonance Enhanced Drilling can be achieved and the optimization of excitation frequency is the resonant frequency of rock drilled.
We suggest that although there are some methods and apparatus have been proposed to achieve resonance drilling technology, more researches are still needed to be conducted to further understand the rock breaking mechanism and promote the realization of the Resonance Enhanced Drilling.

Estimation Method of Natural Water Bodies in the Fracture Cavity Carbonate Reservoir of the Sea

Zhanhua ZHANG, Xue LIU, Junbo YAO, Huiyun WEN, Guanhong YANG — Mon, 26 Jun 2017 00:00:00 +0000

In recent years, the discovery of fractured carbonate reservoirs has made it become a hot spot for the development of such reservoirs. The oil field of south of Bohai is a typical fracture cavity reservoir, which is different from the land oil field. In this oil field, fluid reservoir space is mainly composed of fractures, but caves are not developed, at the same time the reservoir has strong heterogeneity. Oil water relationship and reservoir type are extremely complex and the percolation law is essentially different from the general marine sandstone reservoir. In view of the actual situation of the oil field, the volume of natural water body was studied by reservoir engineering method. By comparative analysis, the results obtained by reservoir engineering method are in agreement with the numerical simulation method. However, reservoir engineering method is simple and rapid, which has a certain reference value for the rapid assessment of water bodies in the same type of oil reservoir at sea.

Optimizing Economic Number of Transverse Fractures in Horizontal Well: A Systematic Design for Maximum Tight Gas Recovery

Saheed Olawale Olayiwola, Md Motiur Rahman — Mon, 26 Jun 2017 00:00:00 +0000

Over the last two decades, the worldwide demand for energy has been met with substantial increase in the oil supply which causes fall in oil price. However, the price of gas has been stabled despite increased demand for gas as a major source of energy. The production from gigantic conventional reservoirs has also reduced which has led to the dependence on current reserves to meet the demand. This increase in demand for gas has led to the increase in activities of research and development with an objective to explore and exploit unconventional resources as an economic and effective cost. Hydraulic fracturing has been proven to be one of the most viable means used to exploit the unconventional resources (tight gas and shale gas formations). Thus, evaluating the performance of the well post-fracturing is necessary to determine the economic viability of the recovery. Inaccurate evaluation of the post-fracturing can lead to either overestimation or underestimation of the design performance particularly from transversely fractured horizontal well. This work includes convergence skin effect that occurs at every intersection of fractures and horizontal section of the well which can account for wide variation of the post treatment in the field from the simulation model. The variation in the skin is a function of fracture conductivity and the number of transverse fractures. This work has developed a hydraulic fracture optimization model which shows the optimal design point, that is, the optimal number of transverse fractures estimated from the economic analysis and gives optimal production rate. This optimal number of transverse fractures estimated from this work is cost effective. This model can lead to an increase in accuracy of optimum design.

Study on the Couple of 3D Geological Model and Reservoir Numerical Simulation Results

xiaoming YE, Chunliang HUO, Bo QUAN, Zhennan GAO, Pengfei WANG — Mon, 26 Jun 2017 00:00:00 +0000

Taking Dongying Formation, Palaeogene, B Oilfield in Bohai Bay Basin as an example, this paper discusses research on coupling 3D geological model and reservoir numerical simulation results during oilfield development. 3D geological modeling technology and reservoir numerical simulation plays important roles in oilfield development nowadays. 3D geological modeling integrates the static information and data from cores, logs and seismic to approach the reality of reservoir as much as possible. Numerical simulation based on geological models, provides a way to use dynamic data by history matching production. Thus, static data from the subsurface reservoir and dynamic data from production are synthesized with the combination of 3D geological modeling and numerical simulation. At present, except upscaling, which connected these two steps, modeling and simulation are usually discussed and operated separately. This paper tried to find an approach to realize the couple of 3D geological modeling and reservoir numerical simulation, which admits the uncertainty of the geological model and emphases the use of simulation result to adjust geological model. 3D geological modeling provides reservoir numerical simulation with initial reservoir static parameter. With the initial geological knowledge, history matching is conducted to quantitatively describe the flowing rule of oil-water. During the process of matching production history, the changes of reservoir parameters may put insight on corresponding geological knowledge. Based on these updated geological knowledge, these possible changes are coupled to the new geological model. 3D geological model of B oilfield was studied as an example in this paper，how to sufficiently integrate numerical simulation results was researched to improve geological knowledge on the connectivity relationship between well groups, then the 3D geological model was updated.