bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Gas in Place Using Optimal Control Theory
Authors: Sinha Mihir K. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the Improved Oil Recovery Symposium of the Society of Petroleum Engineers of AIME, to be held in Tulsa, Okla., March 22–24, 1976. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
This paper presents a procedure for estimating the gas in place for volumetric gas reservoir using the Material Balance Principle and Optimal Control theory. Principle and Optimal Control theory. The reservoir model includes connate water expansion, rock compaction, shale water influx and limited water influx from a bounded aquifer of limited extent. Hydrocarbon phase behavior includes gas compressibility factors.
Validity and predictability of the model have been tested using two published test problems. These problems are:the NS2B Reservoir of the North Ossum Field, Louisiana, andthe Anderson "L" Reservoir in South Texas.
The method was then used to determine the reserve of a large gas reservoir in Wyoming. The results obtained from the Wyoming field have been compared with the results obtained using other methods. The results obtained by different methods agree reasonably well.

Introduction
A reliable estimate of gas in place, recoverable reserve, most probable future life and future production rates, all play very important roles in the Natural Gas Industry. These values are needed for efficient planning of long range contracts and future commitments, scheduling compressor installation, well drilling and other investment decisions. Investment decisions are generally based on profit maximization over the life of the field. Hence, the need for reliable information for management decision can never be over emphasized.
Estimation of gas in place or recoverable gas is one of the most important aspects of gas reservoir analysis. Principle methods of predicting gas in place are:Volumetric MethodProduction Decline Method(Rate-Time, Rate-Cum plots)Material Balance Method(P/Z vs Cum. Prod. plot)
Foam Cementing Applications on a Deepwater Subsalt Well—Case History
Authors: Moore S. , Miller M. , Faul R. , D'Agostino J. 
Published: December 2007

AbstractThe Boris prospect is a deepwater well drilled at Mississippi Canyon. This exploratory well was drilled in a subsalt environment, which provided many zonal-isolation challenges. Deepwater wells in this area can have shallow water flows (SWF),1 long sections of salt, and disturbed zones or rubble zones above and below the salt section. While all these hazards were not encountered during the drilling of this well, foamed cement was an integral part of the plan to deal with them. The paper is a case study of how a new foamed-cementing process was used to solve the challenges associated with the zonal isolation and to help Shell meet the target for the number of drilling days. The paper will cover the cementing process used on three primary casing strings during well construction.
Thermally Induced Wettability Alteration to Improve Oil Recovery in Fractured Reservoirs
Authors: Al-Hadhrami Hamed S. , Blunt Martin J. 
Published: December 2007

Abstract
Many naturally fractured reservoirs are oil-wet and during water injection water will not imbibe into the matrix but will preferentially flow through the fractures resulting in very low oil recoveries. For instance, the Ghaba North field in Oman is an extensively fractured oil-wet carbonate which that has only achieved 2% recovery after over 20 years of production.
Experiments on core from fields in Oman and elsewhere have indicated that the rock will undergo a transition from oil-wet to water-wet as the temperature is increased. The temperature could be increased in a reservoir setting through steam or hot water injection. The wettability change is due to desorption of asphaltenes from the rock surface.
It is proposed to inject steam or hot water to heat the matrix sufficiently to induce a wettability change, rendering it water-wet. Hot water in the fractures can spontaneously imbibe into the matrix displacing oil and resulting in favorable oil recoveries.
A one-dimensional model of the saturation and temperature profiles during imbibition into a matrix block is developed and solved analytically. Example solutions and typical time scales for recovery are proposed. Using Ghaba North properties the imbibition rate is limited by thermal diffusion through the oil. The advancing water front is located where the rock temperature equals the transition temperature for wettability change. It is estimated that around 30% oil recovery could be achieved in single matrix block after approximately 700 days. In less permeable media, the imbibition rate is limited by capillary forces, and the temperature front would move ahead of the water, resulting in slower recovery.
Gel Propagation Through Fractures
Authors: Seright R. S. 
Published: December 2007

Abstract
When gels are used for conformance control in reservoirs, a need exists to determine how much gel should be injected in a given application and where that gel is distributed (i.e., placed) in a naturally fractured reservoir. These parameters depend critically on the properties of gels in fractures. This paper describes an investigation of how Cr(III)-acetate-HPAM gels propagate and dehydrate (i.e., lose water through leakoff) during extrusion through fractures. These studies included fractures with lengths from 0.5 to 4 ft, and heights from 1.5 in. to 12 in., and gel injection fluxes from 129 to 33,100 ft/d.
Based on the experimental results, a model was developed to quantify gel propagation and dehydration during extrusion through fractures. The model indicated that to maximize gel penetration along fractures in field applications, the highest practical injection rate should be used.
Additional tests indicated that significant advantages could be realized for gels made using polymer with the highest available molecular weight. In addition to being potentially more cost-effective, these gels may penetrate deeper into a fracture system than gels made with lower molecular weight polymers.
Increased Oil Production From Bachaquero-01 by Steamflooding Using Horizontal Wells
Authors: Rodriguez M. G. , Mamora D. D. 
Published: December 2007

Abstract
Three-dimensional thermal compositional simulation studies were conducted to evaluate the performance of three horizontal wells under cyclic steam injection and steamflooding in the Bachaquero-01 heavy oil reservoir, Venezuela. In the steamflooding scheme investigated, the horizontal wells were used as injectors with existing (and new) vertical wells as producers. Simulation results indicate: (i) oil recovery of about 15% of original-oil-in-place with cyclic steam injection compared to about 25% under steamflooding with no new producer, and about 50% under steamflooding with additional producers, (ii) main benefits of steamflooding are in re-pressurization and improved thermal efficiency, and (iii) higher oil recovery with additional wells result from improved areal sweep efficiency.
Regional Upscaling: A New Method to Upscale Waterflooding in Heterogeneous Reservoirs for A Range of Capillary and Gravity Effects
Authors: Coll C. , Muggeridge A. H. , Jing X. D. 
Published: December 2007

Abstract
Waterflood sweep efficiency is a function of the prevailing flow regime and the reservoir heterogeneity. However small scale heterogeneities cannot be represented explicitly in field scale simulation models because of limitations in computer speed and memory. Hence pseudo relative permeabilities are used to represent the average effects of small scale heterogeneity on the large scale flow. However many different methods for developing pseudo relative permeabilities are reported in the literature. The best pseudoisation method to use for a particular problem will depend upon the flow regime. For example, vertical equilibrium will apply for gravity or capillary gravity dominated displacements, steady state pseudos can be used for capillary dominated flows whereas dynamic methods can be used for viscous dominated flows. In homogeneous reservoirs the dominant flow regime can be determined from examination of the relevant scaling groups. In heterogeneous reservoirs the flow regime can vary with permeability so different flow regimes may prevail in different parts of the reservoir. Hence different upscaling methods may be needed in different parts of the reservoir. This paper presents the results of the application of a new upscaling methodology called ‘Regional’ upscaling. The method uses dimensionless numbers calculated on a grid block by grid block basis (referred to as ‘Local’ dimensionless numbers) to determine the dominant flow regime in each fine grid cell. The coarse grid is selected based upon the spatial locations of the different force regimes operating in the fine grid simulation model and the pseudoisation method varies across the grid. The method is compared with different pseudoisation methods and its accuracy examined for breakthrough time and recovery prediction for a reservoir in Lake Maracaibo.
Evaluation of Minimum Miscibility Pressure and Composition for Terra Nova Offshore Project Using the New Vanishing Interfacial Tension Technique
Authors: Rao D. N. , Lee J. I. 
Published: December 2007

Abstract
Terra Nova oil pool is the second largest oil pool discovered in the Grand Banks of the Canadian East Coast and is under development with production startup target date in late 2000. As a part of the oil recovery process selection criteria, miscibility conditions were determined for Terra Nova oil with various enrichment levels of gas available from the offshore production facilities, using the newly developed Vanishing Interfacial Tension (VIT) technique.
The VIT technique is based on the concept that the interfacial tension between the gas and crude oil phases at reservoir temperature must reduce to zero as these two phases approach the point of miscibility. The concept of zero-interfacial tension at miscibility is, in turn, based on the well-accepted fact that the interface between the phases must vanish, as they become miscible with one another. Thus, the minimum miscibility pressure (MMP) and minimum miscibility composition (MMC) can be determined precisely by measuring gas-oil interfacial tension as a function of pressure and gas composition, down to as low an interfacial tension as the measurement technique allows, and then extrapolating the data to zero interfacial tension.
This paper presents the details of this new VIT technique and its evaluation against slim-tube tests, and discusses its application to the Terra Nova gas injection scheme. The interfacial tension data obtained at reservoir conditions using the computerized axi-symmetric drop shape analysis technique are presented as a function of pressure, gas composition, and the mode of gas-oil contact (first contact or equilibrium). In addition to providing visual evidence of miscibility as the point of zero interfacial tension is approached, the VIT technique is rapid in that it enables the experimental determination of MMP and MMC within about 2-3 days as against 4-6 weeks required by the slim-tube technique.
Use of the 4-Component Todd and Longstaff Method as an Upscaling Technique in Simulating Gas Injection Projects
Authors: Fayers F. J. , Haajizadeh M. , Lin C. Y. , Taggart J. 
Published: December 2007

Abstract
Gas injection is becoming a significant and economic IOR method, often implemented as a miscible or "near miscible" WAG project. Numerical dispersion effects in standard compositional simulation of WAG processes can cause serious errors in the predicted phase behavior, so that the compositional results for large area models can be very misleading.
The 4-component Todd and Longstaff (T&L) method provides the basis of an upscaling technique, since it approximately represents the physics of these near-miscible processes, and includes five adjustable parameters to facilitate coarse grid T&L matching. The solutions of the T&L equations are well behaved, including less serious sensitivity to numerical dispersion. The upscaling is achieved systematically from a combination of steps with a final stage based on fine grid compositional reference solutions for small representative elements of the reservoir. Details in reservoir description influence the competition between gravity segregation and channeling due to heterogeneities. We illustrate for two example reservoir descriptions how the best choices of the viscosity and density mixing parameters, ωμ and ωρ, can be established by a special optimization procedure. A critical matching requirement is to minimize the errors in distributions of gas saturation. A saving of CPU time by a factor of 2000 is demonstrated for upscaled T&L coarse grid solutions in 2D. We make recommendations on how an upgraded T&L method should be used in reservoir studies.
Predicting Multiple Thermal Fractures in Horizontal Injection Wells; Coupling of a Wellbore and a Reservoir Simulator
Authors: Stevens D G , Murray L R , Shah P C 
Published: December 2007

Abstract
Injection well performance over the long term is often critically dependent upon how the well has been operated during its commissioning period. Whether the well is ultimately to be a seawater (or fresh water) injector or to be used for produced water re-injection, it may be beneficial to commission the well with a different water, probably at a different temperature, since this can have a marked effect upon the initiation of thermal fractures (more precisely these are usually in fact hydraulic fractures that have been initiated at reduced fracture gradients due to near wellbore reservoir cooling).
In long horizontal injectors it is likely that several separate thermal fractures may be generated, and their creation needs to be controlled and managed to ensure optimum well performance. To generate a procedure for the well commissioning requires us to be able to predict bottom hole injection temperature, rate and pressure variation along the horizontal (or highly deviated) section and couple this into a reservoir fracture model. Achieving this using separate models soon becomes impractical, requiring too may iterations between coupled problems.
This paper presents an overview of how an existing commercially available transient wellbore model has been coupled to a special purpose reservoir simulator, and how this has been applied to the modelling of multiple thermal fractures in horizontal injection wells. The paper also reports how the wellbore simulator has been modified to allow the prediction of depth dependent bottom hole temperatures. The paper will also comment on the application of this new coupled model to intervention work in production wells.
Computer Simulation of Carbonate Sedimentary and Shallow Diagenetic Processes
Authors: Matsuda Fumiaki , Saito Michinori , Iwahashi Ryotaro , Oda Hiroshi , Tsuji Yoshinori 
Published: December 2007

Abstract
A computer simulation model Facies-3D carbonate, developed by Japan National Oil Corporation, describes three dimensional carbonate facies based on water depth and current velocity in conjunction with estimated paleo-topography. The Facies-3D carbonate model also contains a module for evaluation of porosity changes in meteoric diagenetic environments. Output data are facies, thickness, and porosity for each grid for the simulation. The above-mentioned calculations are made at each step for the simulation period. Two simulation case studies were conducted using depositional and diagenetic models of the Pleistocene Ryukyu Group in the Irabu Island in the southern Ryukyus, Southwest Japan and the Upper Miocene Kais Formation in the Walio oil field in Irian Jaya, Indonesia.
The study of cores drilled in the Irabu Island clarified that the Ryukyu Group consists of two major lithofacies; the coral limestone facies of shallow shelf environment predominant in the eastern part of the island and the rhodolith limestone facies of deeper shelf environment predominant in the western part. Enhancement of porosity was observed beneath subaerial exposures. The Kais reefal carbonate reservoirs in the eastern Walio field were subdivided into seven shallowing upward cycles, and consist of the fore reef facies in the eastern edge of the area and the back reef facies in the central and western parts. The Kais reservoirs were affected by meteoric diagenesis.
The results of the simulations show that the Facies-3D carbonate model approximated to a high degree, the distribution of facies and the occurrence of porous intervals. The Facies-3D carbonate model can be applied as a tool for reservoir characterization in the field.
Solids Control - The Role Of Sedimentation
Authors: Louden L.R. 
Published: December 2007

Louden, L.R., and Lawson, G.W., Members AIME, Oilfield Products Group, Dresser Industries, Inc.
Discussion of this paper is invited. Three copied of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
A review of the role of sedimentation as applies to oilfield equipment for solids control is presented. By remembering that most all solid removal oilfield equipment except the screen function on an accelerated gravity principle, a proper understanding and use of the available equipment can be principle, a proper understanding and use of the available equipment can be obtained.

TEXT
In many processes it becomes necessary at some stage to separate one liquid from another, or solids from a liquid, or both — problems that have traditionally been solved by filtration or gravity sedimentation. Equipment presently in use in the oilfield for removing solids from mud for plastic viscosity and yield strength control is all based on sedimentation plastic viscosity and yield strength control is all based on sedimentation in one form or another, with one exception. Block diagram in Fig. 1 shows how oilfield equipment may be classified.
This exception, and it is important, is the vibrating screen, a sort of continuous filtration operation, to remove continuously the particles which would form the filter cake. Ironically, the vibrating screen is capable of removing a greater weight of drilled solids per dollar spent than any other piece of rig equipment. Yet it is probably misused and misunderstood by most people.
The remainder of the devices in common use all depend upon the sedimentation operation, and except for settling pits and ditches, these devices are based on enhancing the gravimetric forces to do this job faster, more efficiently, more economically, and in less space.
Often the term separation is used to describe an operation which is not separation at all. (The authors have fallen into this trap in this paper.) When the term separation is used in this paper, it means paper.) When the term separation is used in this paper, it means concentration of one phase or the other to acceptable limits.
Waterflooding the Navette "410" Reservoir
Authors: Simpson G.J.H. 
Published: December 2007

Introduction
One of the earlier waterfloods in Trinidad was in the El Blanco area of the Nanette Field. The El Blanco area was discovered in March 1966 and rapid field development followed, Primary. production was by solution gas drive, and reached its peak during 1968. A reservoir engineering study was made with tee objective of increasing recovery, and a peripheral waterflood commenced in August 1969. Production response to the flood has been generally favourable..

GEOLOGY
The Navette Field is located in the Guayaguayare area of South East Trinidad, forming part of the south eastern flank of the Lizard Springs anticline (see Figure 1). Numerous cross faults occur in the field The El Blanco area, containing the largest fault block, covers the eastern one third of the area. (See Figure 2). Production is from Lower Gros Morne sands of Miocene age. The Lower Gros Morne Zone 4 is one of several Lower Gros Morne sands production in the area, and has been divided into an upper and lower zone, The lower zone consists of a massive fine-grained oil sand underlain by water, while the upper zone is characterized by alternating thin sands and shales. (See type log Figure 3). The sands were derived from a mixed source including volcanic rocks and deposited in the shallow marine, portion of a deltaic complex. The formation consists of vary fine grained sand medium grey, siltstone and shale.
Prospects For Natural Gas Utilization In Trinidad And Tobago
Authors: Ali B. , Houng C. Hee 
Published: December 2007

Abstract
Natural gas, primarily as a by-product of crude oil production has long been in use as a source of energy production has long been in use as a source of energy for refinery processing and electricity generation. During the past fifteen years, a nitrogenous fertilizer industry, based on natural gas, has also been developed. Recent discoveries of substantial reserves of gas in the off-shore areas provide a base for a more diversified industrial development of the country.
The paper reviews the historical development of gas production and utilization. The reserves position with production and utilization. The reserves position with respect to future availability is discussed. The potential for utilization in the following areas is discussed: potential for utilization in the following areas is discussed:as feedstock for manufacture of petrochemicals;as an energy source for large-scale and small-scale energy-intensive industries; andin manufacture of export energy products.
Some criteria for selection of the most desirable development route are suggested and a recommended priority rating is presented. priority rating is presented

Introduction
The discovery of substantial reserves of natural gas in be off-shore areas of Trinidad and Tobago, combined with encouraging prospects for the delineation of further reserves, has prompted investigation of the potential for usage of this gas for the country's industrial development. These studies have focussed on the use of the gas as a raw material for chemicals manufacture, as a source of energy for non-petroleum related industries and as an export energy product. product. This paper outlines the technical aspects of projects that have been identified for possible future development and suggests possible yard-sticks which may be used to aid decision-making with respect to selection of the optimum development route.
P. 79