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The objective of this study was to evaluate the role of strategic mergers and acquisition (M&A) as a panacea for success of marginal oil fields development in Nigeria and to make recommendations for policy decisions. Data for the study were obtained from literature review, document analysis and multiple case studies from operating marginal oil field companies in Nigeria. The cases of Platform Petroleum, Sheba Petroleum, Seplat and others were investigated and analyzed. These case studies identified how marginal field operator's utilized mergers and acquisitions in the form of business restructuring, consolidation, strategic alliances, joint venture formation and partnerships as a development support strategy to remain competitive in the oil and gas industry. Other mergers and acquisitions activities by other companies were also examined. The study findings revealed that strategic mergers and acquisition is one of the survival options for marginal field operators in Nigeria. Mergers and acquisitions enhances the business growth for the marginal oil fields operators by expanding the opportunity for raising capital required for oil and gas operations and provision of larger equity base; including provision of access to technology and manpower. As the oil price in the global oil and gas market remains low, investors in oil and gas business are looking for ways to cope with the fall in revenues. In this dynamic business environment, one fact remains unchanged, marginal oil field operators in Nigeria must re-strategise in order to survive. The marginal oil field operators in Nigeria are encumbered by inadequate funds and other constraints such as lack of capacity, low volume of production and inadequate technology, therefore they have to adopt one of the critical success factors for business survival in a challenging environment. Herein lies the role of strategic mergers and acquisitions. The findings of the study will serves as a decision-making frame work for investors in oil and gas business wishing to participate in the sustainable management of marginal oil field in Nigeria. The study recommendations indicate that policy makers in Nigeria should create a favorable investment climate among which are: stable macro-economic policies, legal system that allows contracts to be enforced and clearly support access to channel of arbitration.
Xu, Wei (CNOOC Research Institute Co., Ltd.) | Chen, Kaiyuan (Beijing Key Laboratory of Unconventional Natural Gas Geological Evalution and Development Engineeing, China University of Geosciences Beijing) | Fang, Lei (Beijing Key Laboratory of Unconventional Natural Gas Geological Evalution and Development Engineeing, China University of Geosciences Beijing) | Zhang, Yingchun (CNOOC Research Institute Co., Ltd.) | Jing, Zhiyi (CNOOC Research Institute Co., Ltd.) | Liu, Jun (CNOOC Research Institute Co., Ltd.) | Zou, Jingyun (CNOOC Research Institute Co., Ltd.)
The lacustrine delta sandbody deposited in the north of Albert Basin is unconsolidated due to the shallow burial depth, which leads to an ultra-high permeability (up to 20 D) with large variation and poor diagenesis. Log derived permeability differs greatly with DST results. Thus, permeability simulation is challenging in 3D geomodeling. A hierarchical geomodeling approach is presented to bridge the gap among the ultra-high permeability log, model and DST results. The ultimate permeability model successfully matched the logging data and DST results into the geological model.
Based on the study of sedimentary microfacies, the new method identifies different discrete rocktypes (DRT) according to the analyis of core, thin section and conventional and special core analysis (e.g., capillary pressure). In this procedure, pore throat radius, flow zone index (FZI) and other parameters are taken into account to identify the DRT. Then, hierarchical modeling approach is utilized in the geomodeling. Firstly, the sedimentary microfacies model is established within the stratigraphic framework. Secondly, the spatial distribution model of DRT is established under the control of sedimentary microfacies. Thirdly, the permeability distribution is simulated according to the different pore-permeability relation functions derived from each DRT. Finally, the permeability model is compared with the logging and testing results.
Winland equation was improved based on the capillary pressure (Pc) data of special core analysis. It is found that the highest correlation between pore throat radius and reservoir properties was reached when mercury injection was 35%. The corresponding formula of R35 is selected to calculate the radius of reservoir pore throat. Reservoirs are divided into four discrete rock types according to parameters such as pore throat radius and flow zone index. Each rock type has its respective lithology, thin section feature and pore-permeability relationship. The ultra-high permeability obtained by DST test reaches up to 20 D, which belongs to the first class (DRT1) quality reservoir. It is located in the center of the delta channel with high degree of sorting and roundness. DRT4 is mainly located in the bank of the channels. It has a much higher shale content and the permeability is generally less than 50 mD. Through three-dimensional geological model, sedimentary facies, rock types and pore-permeability model are coupled hierarchically. Different pore-permeability relationships are given to different DRTs. After reconstructing the permeability model, the simulation results are highly matched with the log and DST test results.
This hierarchical geomodeling approach can effectively solve the simulation problem in the ultra-high permeability reservoir. It realizes a quantitative characterization for the complex reservoir heterogeneity. The method presented can be applied to clastic reservoir. It also plays a significant positive role in carbonate reservoir characterization.
Jaja, Adagogo J. (Chevron Nigeria Limited) | Okani, Nnamdi (Chevron Nigeria Limited) | Eme, Vincent (Nigeria Limited) | Ricardos, Ricardo Combella (Chevron Nigeria Limited) | GOM, Chevron (Chevron Nigeria Limited) | Silpngarmlers, Lynn (Chevron Nigeria Limited)
In the Early phases of field development, the drilled hydrocarbon appraisal wells may not have been sufficient to define rock properties, fluid typing and contacts. It's very important to define the range of uncertainty in such fields. This is because as the field matures other dynamic data will become available to validate these probable volumes.
The ideal development scenario provides the practitioner with a full suite of data defining the reservoir geometries, reservoir properties, fluid properties etc. to make subsurface decisions. However, in most cases, operational realities will deny the reservoir practitioner this full suite of data.
One practical convention that is used to resolve this data paucity challenge is to evaluate and report the lowest possible volume, if this low case is economic the project will be economic with potential for more upside outcomes. However, a challenge that can arise with this is that after several iterations the low case can become the only case. A better practice is to characterize uncertainty of reservoir parameters during the early stages of field development and carry out the full range outcomes through the field's life. These ranges will then be validated as the field matures.
This paper demonstrates a case in the Niger Delta field A05 reservoir were dynamic simulation model was used to narrow the uncertainty range on the GOC. Proper identification and characterization of the GOC uncertainties helped for the estimate of a range of STOOIP used for dynamic simulation model. Though no static dataset was available to reduce this uncertainty on the GOC, during dynamic simulation, the high-case oil in-place volume was found to be the best match to historical production data with the integration of another reservoir, Delta A12, in one dynamic simulation model. Both reservoirs communicate through the aquifer, separated by a saddle. This then proved up additional volumes in the reservoir, identified previously overlooked reserves and allowed the asset team to propose an extra infill well opportunity than what was previously planned. This new understanding of the A05 reservoir increased the oil estimated ultimate recovery (EUR) by 4.6 MMSTBO.
Corporate social responsibility has become a business imperative as organization deliberately and strategically include public interest on corporate decision in an attempt to satisfy the demand of sustainable development. Balancing short term sight and long term perspective against triple bottom requirements in the face of rapidly changing social environment presents uncharted challenges and opportunities for businesses. For marginal oil field operators located in the Niger Delta, the region is characterized by poverty, underdevelopment and violent conflicts. The study investigated the strategies adopted by marginal oil field operators in the region to achieve competitive advantage and success. Combining several methodological framework through literature review and multiple firm level case study to examine the various strategies that marginal oil field operators in Niger Delta region adopts in their efforts to becoming social responsible corporate entity. Data gathering is through internet and review of existing literature. The study established that marginal field operators may apply different strategies in responses to social demands in their operating environment. It is observed that the dynamic response or interactive strategy have produced beneficial result by sustaining peace in their operating environment in the long run compared to reactive or adaptive strategy which might gain temporary benefits in the short run. The significance of the study is that it would benefit investors in marginal oil field development as it would provide an understanding of the challenges in the business environment and the different strategic responses needed to handle these challenges. The study recommends that investors in oil and gas business assess their operating environment carefully in order to develop strategies that would result in a cost effective way of managing business and bring about harmonious relationship between the host communities and the oil company.
Xu, Wei (CNOOC Research Institute Co., Ltd.) | Zhang, Yingchun (CNOOC Research Institute Co., Ltd.) | Fang, Lei (CNOOC Research Institute Co., Ltd.) | Jing, Zhiyi (CNOOC Research Institute Co., Ltd.) | Zou, Jingyun (CNOOC Research Institute Co., Ltd.) | Liu, Jun (CNOOC Research Institute Co., Ltd.)
The Albert Basin of Uganda is located at the northern end of the western branch of the East African Rift System. It is a graben rich in oil and gas with a shallow research degree. In the south of the basin, a fan delta system controlled by the boundary fault is developed in the Miocene formation. Due to the few wells and poor quality of seismic data in this area, it is difficult to predict the spatial distribution of sedimentary reservoir sands. In this paper, sedimentary forward modeling coupled with 3D geological modeling is used to provide new ideas for reservoir prediction.
Sedimentary facies analysis is based on core description, well logs, paleontology, heavy mineral content and grain size data. Quantitative analysis of accommodation space, source supply, and sediment transport parameters can help explain the main factors that controlled the sedimentation. Milankovitch cycle method was used to establish the time scale of the basin. The simulation results were combined with 3D geological modeling to quantify the characteristics of the sand body distributions.
Sedimentary facies analysis shows that the Miocene formation in the south of Albert Basin deposited in a shallow lacustrine environment. A proximal fan delta deposition with subaqueous distributary channels was controlled by the east boundary faults. Firstly, the accommodation space was estimated according to the thickness of the stratum and the change of the ancient water depth. The source supply was estimated by the area of the project and formation thickness, and the transportation parameters were estimated according to the nonlinear transportation model based on the traction flow with a little gravity flow. Secondly, an astronomical stratigraphic framework of the Miocene strata in the south of Albert basin was established through the Milankovitch cycle stratigraphy, and it was used to restrain the process of stratigraphic forward modeling and to reproduce the sedimentary evolution process in the geological historical period. Thirdly, the stratigraphic forward modeling results were resampled into the geological model, a 3D reservoir probability distribution model is established from trend modeling to quantitatively characterize the spatial distribution of sand bodies. Finally, the sandstone distribution simulation results were transformed into quantitative control constraints for 3D geological facies modeling. Thus, the new approach significantly promotes the facies model quality and provides robust results for petrophysical property models.
Integration of stratigraphic forward modeling with 3D geological modeling can effectively solve the problem of reservoir characterization in an early stage of oilfield development through the interaction of the dual model coupling. This method has unique advantages in the reservoir research in the area with fewer data and great variation of sand.
Cai, Junjie (Shenzhen Branch, CNOOC China limited) | Wen, Huahua (Shenzhen Branch, CNOOC China limited) | Gao, Xiang (Shenzhen Branch, CNOOC China limited) | Cai, Guofu (Shenzhen Branch, CNOOC China limited) | Hu, Kun (Shenzhen Branch, CNOOC China limited)
Huizhou Depression is in the exploration peak stage at present. The main target layer is gradually extending from the middle-shallow traps to the deep paleogene traps and the shallow lithologic traps, and the difficulty of exploration is totally increased. Paleogene layer oil&gas exploration is faced with the problems of deep buried depth, reservoir heterogeneity and uncertain distribution of high-quality hydrocarbon sources.
By combining tectonic evolution analysis with sequence stratigraphy, considering regional stress background and the utilizing of the seismic facies, the main faults tectonic features, stratigraphic sedimentary characteristics, the distribution position of sedimentary center and the control effect of the palaeogeomorphology on the sedimentary distribution range deposited from the transition zone are analyzed.
It is concluded that the lower Wenchang period's tectonic movement was dominated by the southern depression control fault, and the semideep-deep lacustrine high-quality hydrocarbon source rocks were mainly distributed in the south of the Huizhou Depression, such as HZ 26 Sag and the subsag of the XJ30 Sag. The braided river delta deposited from XJ30 transfer zone is mainly distributed along the west side of the long axis of XJ30 sag, and the semideep-deep lacustrine facies mudstone is formed in the east of XJ30 Sag. In the upper Wenchang period, the activity of the depression control faults in the northwest of the Huizhou Depression becomes stronger than the south, which influences the sedimentary center migrated from southeast to the northwest. The sediment provenance of XJ30 transfer zone deposits perpendicular to the long axis of the XJ30, and the long braided river delta is formed in the south side of the XJ24 Sag. In Enping period, which is changed from strong rift phase to rift-depression transition phase, the shallow lacustrine-swamp facies are taken as the main source rocks, and shallow braided river delta is widely developed, while the sediment from the provenance of XJ30 transfer zone is weakened.
The northern and southern migration of the transfer zone provenance river delta and the northern and southern distribution characteristics of the source rocks of semideep-deep lacustrine facies are caused by the differences of the northern and southern fault activities during the Paleogene period. Through the combination of structural evolution analysis and sedimentary characteristics analysis, the analysis of paleogeomorphology's effect on the control of sedimentary system is of great importance to the identification of high-quality paleogene reservoirs and hydrocarbon sources.
In the Freeman Field, located about 120km offshore southwestern Niger Delta at about 1300m water depth, 3D seismic attribute-based analogs, and structural and stratigraphic based geometric models are combined to help enhance and constrain interpretation. The objective of this research was to aid in the prospecting of Miocene to Pliocene Agbada Formation reservoirs in the deep offshore Niger Delta Basin. Multidisciplinary approaches – analysis of root-mean-square amplitude attribute, iterative integrated seismic interpretation and structural modeling, were employed in this study. Results reveal a massive northwest-southeast trending shale-cored detachment fold anticline containing numerous associated normal faults. This structure is interpreted to have been deformed by differential loading of the undercompacted, overpressured, and ductile Akata shale during syndepositional gravitational collapse of the Niger Delta slope. Crestal extension in the anticline resulted in a complex array of synthetic and antithetic normal faults, which include crossing-conjugate pairs. These conjugate structures could significantly affect permeability and reservoir performance. Crossing-conjugate faults have not previously been recognized in the Niger Delta, and similar structures may be present in other hydrocarbon-trapping structures in the basin. Also, the Miocene to Pliocene Agbada Formation reservoirs occur as part of a channelized fan system, mostly deposited as turbidites in an unconfined distributary environment, except one reservoir sand that occurs as channel sand within a submarine canyon that came across and eroded a previously deposited distributary fan complex, suggesting likely presence of prospective areas for hydrocarbon exploration southwest of the Freeman Field.
Presentation Date: Thursday, October 18, 2018
Start Time: 8:30:00 AM
Location: 210A (Anaheim Convention Center)
Presentation Type: Oral
Jaja, Adagogo J. (Chevron Nigeria Limited) | Ambastha, Anil (Chevron Nigeria Limited) | Aina, Soji (Chevron Nigeria Limited) | Eme, Vincent (Chevron Nigeria Limited) | Bere, Barienea (Chevron Nigeria Limited)
Reservoir simulation is one subject with different "schools of thought" for its ability to predict the future performance of a reservoir. An important topic in reservoir simulation workflow is the parameters used to achieve history-match. The non-uniqueness of history-match parameters creates an opportunity for reservoir simulation engineers and geologists to engage in collaborations that ensure geological and engineering interpretations are incorporated in history-match parameters.
Simple history-match parameters are often times preferred by practitioners to complex history-match parameters. This paper will discuss Delta reservoir history-match parameters used in a 2014 reservoir simulation study which was later updated in 2016 with simplified history-match parameters. The parameters that were simplified are permeability multipliers, oil/water relative permeability and the use of Land's constant. Also, vertical grid refinement was implemented to reduce it from 8ft to 2ft to enable the simulation model reproduce the reservoir fluid distributions in the two lobes of the reservoir. With all these modifications, there were no significant differences with the wells’ static reservoir pressure and fluid saturation matches between the 2014 simulation study and the 2016 simulation update. This paper demonstrates the non-uniqueness of reservoir simulation history match parameters and the value to consider simple grid and fluid parameters’ modification before considering complex approach.
With the simplified history-match parameters, the Asset Team had more confidence in the simulation result. The updated Delta reservoir simulation model was used to assess future development opportunities and identified two oil-well producers and one water injector well with EUR of 13.3 MMSTBO.
Magnetic resonance (MR) data were acquired in a six-frequency PoroPerm + Light Oil mode in the study well. The acquired data had a low signal-to-noise ratio from midpoint to the top of the logged interval. This ratio could adversely affect the suitability of this data for hydrocarbon fluid typing and saturation computation.
Examination of the detailed quality control plot showed high B-pulse ringing on the two lowest and the third highest frequencies, A-pulse ringing on the two lowest frequencies, and noise on the two lowest frequencies. The affected frequencies could not be used for fluid typing analysis. The reduction in the total number of available frequencies resulted in a high diffusivity, especially in the gas-bearing reservoir sand. High diffusivity caused some of the movable fluids to appear as irreducible bound water. The low hydrogen index of the gas also caused a low-permeability profile.
Despite the failure of some of the acquired frequencies, there was a need to identify and quantify the fluid type in the reservoir. Several fluid-typing techniques where employed to find a suitable technique for this dataset. After trying Multiple Gradient Inter-Echo Time (MGTE) analysis, the Simultaneous Inversion of Multiple Echo Trains (SIMET) module, and a 2D NMR (
The fluid typing result from
Horizontal wells increase the reservoir-wellbore contact area, allowing the wells to produce at higher flow rates with smaller drawdowns which is especially important in oil reservoirs with a large gas cap or aquifer. Long wellbore lengths can lead to production challenges such as water or gas coning and cusping, an unwanted fluid breakthrough from high-permeability zones, and uneven inflow along the wellbore and nonuniform reservoir sweep.
Inflow control devices (ICDs), based on well-established technology, have been used in hundreds of wells worldwide. Different ICD types and design methods are available and can be applied to mitigate some of the production challenges. The ICDs are installed as an integral part of the sand screens in the well completion hardware. They can be passive, where the ICD size and configuration does not change after it is run in the hole, or autonomous, where the ICD adapts to changes in downhole fluid-flow properties. However, the decision regarding the use of ICDs as well as the design criteria and selection has to be made prior to the well completion operation.
This paper presents a feasibility study on an ICD application in an offshore Nigeria delta oil field with multiple hydrocarbon-bearing reservoirs. Most of the development wells in the field have horizontal openhole 1,000 to 3,000 ft drain sections completed with standalone screens. Strong aquifer and reservoir heterogeneity create production challenges associated with early water breakthrough and suboptimal reservoir sweep. This paper presents a detailed approach to ICD design, sensitivity analysis, and completion optimization, which is based on the coupling of a 3D reservoir model, segmented wellbore model, and ICD models. The proposed ICD completion design is evaluated and sensitized to subsurface reservoir uncertainties using volumetrics. The final decision process is presented to guide the selection and feasibility of an ICD application for two reservoirs.