bluuebunny/crossref_metadata_2025_split huggingface dataset:
EOR Methods to Enhance Gas Oil Gravity Drainage:Modeling Aspects
Authors: Boerrigter P. M. , Verlaan M. L. , Yang D. 
Published: December 2007

Abstract
Conventional displacement methods such as water flooding do not work effectively in densely fractured reservoirs: due to the high fracture permeability it is not possible to establish significant pressure differentials across oil bearing matrix blocks to drive oil from matrix rock towards producers. In such reservoirs one has to rely on natural mechanisms like capillary imbibition or gravity to recover oil from the matrix reservoir rock. In Middle-East fractured carbonates, the matrix rock is commonly oil-wet or mixed wet and only gravity drainage remains a feasible process. However, permeabilities are usually low, &lt;10 mDarcy, resulting in low gravity drainage production rates with high remaining oil saturation and/or capillary holdup.
EOR techniques such as steam injection and miscible gas injection have the potential to improve GOGD rates and recoveries: –In shallow fractured reservoirs it is possible to inject steam in the fracture system. Steam will condense as long as it contacts cooler matrix rock, resulting in a steam front that develops in a stable way through the fracture system. Heating of the matrix will result in oil expansion, reduction of viscosity, gas drive and stripping effects.–In deeper reservoirs GOGD under miscible conditions becomes an option. Injection gas that is miscible with the oil will result in swelling and viscosity reduction, both increasing oil mobility and therefore improving the GOGD rates. Miscibility further adds the advantages of single-phase flow at high effective relative permeability and reduced interfacial tension, thereby reducing re-imbibition effects and increasing ultimate recovery from inhomogeneous reservoirs.
To assess the benefit of these EOR methods, simulation techniques should be capable of modelling the impact of these processes on GOGD. We present in this paper a general dual permeability method that can handle GOGD as well as different, mutually interacting, processes expected to occur when EOR techniques are applied to fractured reservoirs.
Innovative Pattern Balancing and Waterflood Optimization of a Super Giant Carbonate Mauddud Reservoir, Sabiriyah Field, North Kuwait
Authors: Al-Ajmi Moudi , Baroon Bodoor , Al-Hamer Mohammad , Al-Anzi Ealian , Al-Muwail Majeed , Al-Anzi Hamed 
Published: December 2007

Abstract
Sabiriyah Mauddud (SA MA), a super giant depletion drive oil reservoir in North Kuwait (NK), is undergoing massive development efforts, with a planned enhancement in oil production through phased pattern waterflood. The Phase1 development covers the crestal area of the structure, which is the focus for current development efforts through 12 inverted 9-spot patterns. This paper outlines the successful integration of subsurface, water handling, well surveillance and production operations teams across the NK asset to significantly improve the operating procedure for waterflooding the SA MA reservoir. This effort required a new way of managing this reservoir in NK: a comprehensive approach of balancing voidage with injection, conducting extensive surveillance/analysis within the reservoir to assess the efficacy of various courses of action and, most significantly, adjusting various teams’ "key performance indicators" to align injection and production allowables with sound reservoir management principles.
The health of the waterflood is regularly checked and monitored through revision of production/injection allowable and pattern balancing. An innovative unified information management system was used to monitor voidage replacement ratio (VRR) to provide a basis for pattern balancing. A very extensive surveillance operation provides the data necessary to monitor individual pattern balance and watercut performance, optimize areal sweep efficiency by adjusting injection and production allowables, assist in planning water shutoff operations, and design new completions.
Time lapsed monitoring and the surveillance data indicates the reservoir is relatively well connected. Pattern VRR, pressures, and watercuts were somewhat out of balance prior to engaging in this effort. However, after applying the new management approach, individual waterflood pattern balance is significantly improved and the field-wide VRR is around 1.2.
All of these activities have led to the enhanced understanding of the waterflood behavior and the model updates. Sound reservoir surveillance and waterflood management procedures implemented within a diverse group of teams that have performance goals aligned with "best practice" has resulted in effectively re-balancing this major waterflood. This effective integration of teams retains the flexibility to adjust for an ongoing development of this super giant field. This paper also brings out the case history of waterflood management in a super giant carbonate reservoir and the challenges met during the last seven years since the commissioning of the waterflood in year 2000.
Sensitivity Analysis of Important Parameters Affecting Minimum Miscibility Pressure (MMP) of Nitrogen Injection into Conventional Oil Reservoirs
Authors: Vahidi A. , Zargar Gh. 
Published: December 2007

Abstract
Nitrogen has been found to be a suitable recovery agent for conventional oil with API gravity larger than 35 that provides the reservoir pressure is above the minimum miscibility pressure and the reservoir oil contains a high concentration of intermediate hydrocarbon components. Nitrogen has been found to achieve dynamic miscibility at high pressures. The miscibility obtained by nitrogen injection in light crude oil reservoir is a conditional miscibility, where the fluids are not miscible on first contact, but form two phases, with one of the fluids absorbing components from the other. After sufficient contacts and exchanges of components, at minimum miscible pressure, the system becomes miscible.
The main purpose of this study is to investigate, the effect of temperature, composition of the reservoir fluid and injected gas, on the MMP of nitrogen injection in light oil reservoir by a simulator. The injected gas is pure Nitrogen or a combination of nitrogen with other gas like propane. The effect of varying the percentage of nitrogen and CO2 in the injection gas mixture on MMP has been previously investigated by experiment.
Results of the Simulation have shown that the most important factor to achieve miscibility between nitrogen and reservoir oil is the amount of light and intermediate components in the oil. Increasing the intermediate components and decreasing the methane content decrease the MMP. Nitrogen develops miscibility of oil by the same mechanism as methane (vaporizing gas drive). With sufficient amount of methane in oil reservoir, MMP of nitrogen and methane injection is almost the same but decreasing the methane content causes difference. Studies have shown that injecting nitrogen-propane combination will decrease MMP but combining nitrogen with methane does not have significant effects on the MMP. Result show that MMP of nitrogen increases slightly when temperature decreases.
Development and Application of an Integrated Clustering/Geostatistical Approach for 3D Reservoir Characterization, SACROC Unit, Permian Basin
Authors: González R. J. , Reeves S. R. , Eslinger E. , GarcÍa G. 
Published: December 2007

Abstract
A new 3D reservoir characterization approach is developed that integrates clustering and geostatistical methods. The approach applies clustering methods to well logs and core data for lithology interpretation, reservoir quality characterization, and also for prediction of core porosity and permeability values. Since complete log suites are usually unavailable, clustering is also used to generate synthetic "complete" log suites. In this way, "core" parameter profiles, with high vertical resolution, can be generated for many wells. Geostatistics is then applied to the resulting dataset, and three-dimensional spatial patterns of clusters, porosity, and permeability are utilized to generate reservoir characterizations for flow simulation models.
An advantage of the approach is the application of a soft computing software based on maximum likelihood principles which permits clustering using mixed variables; probabilistic assignment of samples to each multi dimensional cluster; prediction of missing data during the process; lithology estimation of clusters based on a built-in "expert" system; and development of multiple relationships among core and log data for each cluster.
The approach was applied in the platform area of the SACROC Unit (Permian basin), acknowledged as a highly complex carbonate reservoir. In 2004 and 2005, three wells were drilled in this area, were fully cored through the reservoir (~ 800 ft) and porosity and permeability measurements taken on a foot-by-foot basis.. These measurements jointly with modern well logs were utilized to develop models that firstly predict acoustic impedance (product of sonic and density) from only gamma-ray and neutron porosity logs (widely available), and secondly porosity and permeability from these three combined logs. The generalized models, applicable across the platform area, have successfully replicated acoustic impedance where independent data existed for verification, as well as previously acquired core data. This seems to validate the applicability of the new approach in this highly heterogeneous carbonate reservoir.
Unlike seismic inversion and other "data mining" or geostatistical approaches for 3D reservoir characterization, the method described herein can yield, based on the presented example, what appears to be a high resolution result consistent with the known reservoir character.
Detection of Bottom Water Movement Using Well Test
Authors: Ekong Inem S. , Onyekonwu Micheal O. 
Published: December 2007

Abstract
The traditional well testing concept and the mathematical formulations of diffusivity equations for a radial flow system, was used to develop mathematical models for a reservoir-aquifer system incorporating bottom water flow in the vertical direction, considering various reservoir internal boundary and aquifer external boundary conditions. Laplace transformation was utilized in solving the resulting diffusivity equations and inverted to real space using Stefhest Algorithm to obtain dimensionless pressure drop, dimensionless rate and dimensionless cumulative influx with dimensionless time, as a series of constant pressure bottom boundaries. A MS-Visual Basic program was developed to enable quick solutions to be obtained for the Laplace transformation and Stefhest Algorithm expressions at various inner and outer boundary conditions.
The results are presented in graphical and tabulated forms, which are believed to be convenient for engineering use. The developed models were validated with some published work in literature. The pressure and rate transient behaviour of the reservoir-aquifer system as the aquifer bottom water moves in or out of the reservoir was analyzed for the various boundary conditions used in the development of the models.
The developed models can also be used to detect bottom water movement, predict reservoir pressure schedule given water influx rate or cumulative influx and influx rate/cumulative influx can be predicted given reservoir pressure schedule. An example problem using a typical Niger Delta field bottom hole pressure (BHP) survey data was applied with the developed models in the detection/prediction of aquifer bottom water movement.
Economic Implication of Steerable Casing While Drilling
Authors: Busola Oguntuberu Toyin 
Published: December 2007

ABSTRACT
This research aims at proffering a drilling method which would save time and reduce cost while solving borehole problems during the drilling of a directional well.
This was done by performing a case study on two drilling methods. Case one was Conventional Drilling Method (CDM) model and Case two was Steerable Casing while Drilling Method (SCwD) model.
Better drilling technique was recommended based on the conclusion reached from the data acquired through secondary research, comparative analysis preformed on time, cost saving and reduction revenue lost due to open hole associated problems using both methods. SCwD should be adopted for improved application of directional drilling in field development.
Constructed Treatment Wetlands: Innovative Technology for Petroleum Industry
Authors: Eke Paul Emeka , Scholz Miklas , Wallace Scott D. 
Published: December 2007

Abstract
Constructed wetlands are innovative and inexpensive treatment approaches that have the potential of removing organic such as aromatics components [benzene, toluene, ethylbenzene and xylene (BETX)] and inorganic compounds in wastewater from a range of sources. The traditional treatment technologies used by the oil industry such as hydrocyclones, separators, etc. removes only dispersed oil but could not remove aromatics components in dissolved water phase. Despite the effectiveness, environmental friendliness and positive economics of constructed treatment wetlands, the application of this novel wastewater treatment technology is still rare in the petroleum industry.
The study investigates the potential of aromatic hydrocarbon removal in constructed wetland and consequently advancing proper understanding of scientific and optimal operating conditions of constructed treatment wetlands in the petroleum industry. The research focuses on the investigation of the measures to improve the treatment efficiency of contaminants, assessment of the role of the main constructed wetland components and boundary conditions impacting on the operation and treatment performance.
Twelve vertical-flow experimental wetland filters have been designed, constructed using different filter media, and were operated in batch-flow mode to reduce operating cost. The experimental filters were designed to optimize the chemical, physical and microbiological processes naturally occurring within wetlands. Six filters were located indoors, and six outdoors. The outdoor rig simulates natural weather conditions while the indoor rig operates under controlled environmental conditions such as regulated temperature, humidity and light. Findings indicate that the constructed wetlands successfully remove aromatic hydrocarbon (benzene inflow of approximately 1 g L−1) from simulated produced waters with better indoor treatment performances than the rig placed outdoors.
This result suggests that constructed treatment wetland is very attractive, sustainable and innovative technology capable of meeting zero discharge goal in the production, storage, refining and transportation sectors of the oil and gas industry.
Determination of Temperatures for Cementing in Wells Drilled in Deep Water
Authors: Calvert D.G. , Griffin T.J. 
Published: December 2007

Abstract
The American Petroleum Institute (API), Sub-committee 10 (Well Cements) has developed temperature correlations for estimating circulating temperatures for cementing. These correlations use the true vertical depth and a single temperature gradient (computed from the bottomhole static temperature) to make the estimation.
Often wells have temperature transitions meaning that there is a change in temperature gradient below a transition zone. Wells drilled below bodies of water likewise have a temperature transition in the form of the change from water to earthen formations. This can be relatively insignificant, except in the case of large water depths (generally considered to be 1500 ft or more). Such environments are currently being drilled in the U. S. Gulf Coast, Northern Europe, Africa, Brazil, Middle East and Far East. At such water depths, a compounding problem is that the water temperature decreases, approaching the freezing point of water at great depths. It is not uncommon in these areas that the temperature at the mudline or seabed is 40 F or less. Not only is the water temperature low, but formations close below the seafloor are cold also.
This paper describes temperatures in wells drilled in deep water. Computer simulations of wellbore temperatures are presented. Additionally, the simulations show the effects of factors not taken into account by the API correlation. These factors include circulation rate and time, temperature of the injected fluid and sea temperature and currents, to name a few.
Failure to account for the correct temperature can result in greatly extended cement setting times and lead to long delays in continued rig operations. With the rates for deepwater drilling rig operations in the range of $200k-300k per day, any delay in drilling out can increase well costs considerably. Even more importantly, such delays can allow the flow of gas and/or water from shallow overpressured formations, potentially leading to erosion and catastrophic failure of the entire well and surrounding structure, with losses in the hundreds of millions of dollars.
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A Robust Torque and Drag Analysis Approach for Well Planning and Drillstring Design
Authors: Adewuya Opeyemi A. , Pham Son V. 
Published: December 2007

Abstract
This paper presents a novel torque and drag analysis approach and demonstrates its robustness when used with a versatile computer program. Torque and Drag analysis remains an important evaluation process for assessing drilling feasibility of directional wells, minimizing the occurrence of catastrophic drill string failures and avoiding premature termination of the drilling operation before reaching planned target depth.
From a draft well plan, the drilling engineering analysis is initiated with the development of a representative analytical model using selected entries in a Torque and Drag computer program. Several parameters and instances of evaluation are needed to capture the physical behavior of modeled systems and to produce technically sound results.
The availability of computational tools have not necessarily improved the drilling engineering process or enhance the quality of recommendations without a methodical approach and application of results.
To minimize the iterative steps required to reach an interpretable result, the analytical process as presented in this paper is accelerated with a directed search and a convergence to the determinant drilling variables. The novel approach narrows – the design search domain and tests sensitivities of well-plan characteristics, simulates drilling conditions and applicable drillstring – to the dominant operating factors that determine the boundaries of application.
A record extended reach well (MD/TVD ratio of 2.9) with a lateral displacement of approximately 6,000 ft. was drilled in the GOM using this approach to select tubulars and their position in the well with respect to dogleg severity, inclination and target objectives.
Development of Steerable Ream While Drilling Technology and Its Application in High Angle Wells in GOM
Authors: Cook John , Doster Michael , Dykstra Mark , McDonald Scott 
Published: December 2007

Abstract
Newly developed technology that allows simultaneous reaming and drilling with steerable assemblies has dramatically improved the economics of an extended reach program in the Gulf of Mexico. This paper details the development and application of this unique technology.
The technology development phase comprised laboratory and field tests which examined the dynamic stability and steerability of prototype technology. Laboratory tests confirmed that the pilot stabilization pad (PSP), which is a key feature of the reaming tool, provided enhanced stability in the drilling mode, and expedited the transition from pass-through to drill diameter in the hole opening mode. Field tests proved that the increased length of the reaming system (compared to a bit alone) did not have a negative impact on directional performance of steerable assemblies.
The technology was applied in two intervals in an extended reach well in the Gulf of Mexico. The first interval utilized a 17 in. steerable ream while drilling (SRWD) system with a 9.875 in. roller cone pilot to build inclination at 3 deg/100 ft to 65 deg. The second interval used 9.875 in. SRWD equipment with a 6.5 in. polycrystalline diamond compact (PDC) pilot bit to hold angle near 62 deg over a 8,371 ft interval. Combined, the application of SRWD technology in these intervals reduced drilling time by 17 days, and saved $1,190,000 in drilling cost.
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Development of a One-Trip ECP Cement Inflation and Stage Cementing System for Open Hole Completions
Authors: Coronado Martin P. , Knebel Mark J. 
Published: December 2007

Abstract
Drilling of horizontal wells continues to increase worldwide. A significant number of these wells are completed with either screen or slotted pipe across the production intervals. Many of these completions require some form of annular isolation to separate different geological zones and to isolate the upper wellbore. As a result, open hole completions are becoming more sophisticated, requiring a systems approach during the installation phase of the operation. Operators are also requiring that these completions be installed with the fewest drill pipe trips as possible to save time and reduce costs.
The new integrated system described in this paper allows the production liner to be run into the wellbore and a liner top hanger system set, multiple external casing packers (ECPs) selectively cement inflated at target locations to provide zonal isolation and then the radius section of the production liner cemented to provide isolation between the liner and upper casing string. Using a newly designed hydraulically-operated cementing valve positioned in the liner above the uppermost ECP, the build section of the liner can be cemented after all the ECPs have been inflated. Using a workstring inside the liner in conjunction with a selective ECP inflation tool, cement can be displaced down the workstring, through the cementing valve, and out into the annulus.
This new open hole completion method has been demonstrated to significantly reduce rig time during the installation phase, and provide the annular zonal isolation required by operators. The system also leaves the production liner free of cement, making subsequent cleanout runs unnecessary.
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Selective Isolation of Perforated Liners Using Casing Patches: Case Studies from North Sea Operations
Authors: Forbes Charles , Taggart Ian 
Published: December 2007

Figures are not available for this paper.

Abstract
The Weatherford Internal Steel Liner casing patch has been used for many years to mechanically seal off perforations when the completion has been pulled for workover operations.
Recent work has shown that it is possible to carry out this operation with the completion still in place using a Coiled Tubing (CT) or Hydraulic Workover Unit (HWU) to run the Patch. This has offered substantial technical and economic advantages.
The latest development of the tool, a mechanical patch to pass through a 4" restriction and set in a 7" 29ppf liner and will address the majority of North Sea wells.
This Patch system offers an effective mechanical seal option to reduce water production.
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