bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Transport in a Microporous Silica Membrane
Authors: Hassan Mohammed H. M. , Way J. Douglas
Published: December 2007

The permeances of several gaseous species (He, H2, CO2, N2, CH4, and C2H4) were measured through silica hollow fiber membranes over a temperature range of 298 to 473 K at a feed pressure of 20 atm. Permeances ranged from 10 to 2.3 * 105 Barrer/cm at 298 K and were inversely proportional to the kinetic diameter of the penetrant. The permeance of gaseous species were found to decrease with decreasing differential pressure driving force at ΔP <5 bar. No pressure dependency was found at ΔP > 5 bar. Mass transfer through the silica hollow fiber membrane was found to be an activated process. Activation energies for diffusion through the silica membrane calculated from the slopes of Arrhenius plots of the permeation data ranged from 4.61 10 14.0 kcal/mole and correlate well with the kinetic diameter of the penetrants. Large separation factors were obtained for the penetrants. The separation factors decreased with increasing temperature. The CH4/CO2 mixed separation factors were higher than the values calculated from pure gases at temperatures below 373 K. This behavior was observed after the membrane had been heated to at least 398 K and then cooled in an inert gas flow. The differences between the mixture and ideal separation factors is attributed to a competitive adsorption effect in which the more strongly interacting gases saturate the surface and block the transport of the weakly interacting gases.
As Built, the Achievable Goal; ADCO's Experience
Authors: Muflahi Ali Kassim
Published: December 2007

This paper describes the transformation of Abu Dhabi Company for Onshore Oil Operations' (ADCO's) drawing, documentation and tagging system from a traditional manually orientated approach to a procedure dictated electronically based system aimed at producing high integrity ‘As-Built’ documentation together with standard identification of equipment. A project was initiated, in 1992, to implement the new system and this is described together with measures being taken to maintain the integrity of the system. The discussion highlights the benefits of the system and touches on future developments and the difficulties encountered.
Take It to the Limit: The Dynamics of Rod Load and Rod Reversal in Reciprocating Compressors
Authors: Gajjar Hasu
Published: December 2007

A major factor the engineer must consider when designing a reciprocating compressor package is the structural limit of the compressor. This limit is referred to as the rod load or frame load and is the maximum continuous operating force the compressor can safely withstand. Our discussion will include static rod load, inertia rod load, dynamic rod load, and rod reversal, with guidelines for minimizing rod reversal in the field.

Introduction

Every compressor has speed and load-carrying limitations. Primarily, the load-carrying capacity of a compressor frame involves horsepower and rod loading. Rod load specifications tell the compressor package operator the limits of static, inertial, and dynamic loads that can be borne by the crankshaft, connecting rod, frame, piston rod, bolting and bearing surfaces. This knowledge and how it is applied can make the difference between downtime and runtime.

Mechanics of Principal Moving Parts

The forces acting on the principal moving parts of a reciprocating compressor are:

- The gas pressure forces

- The inertia forces of the reciprocating parts

- The dynamic forces of the reciprocating parts

- Centrifugal forces of the rotating parts.

I will address all except the centrifugal forces in this presentation.

The gas pressure forces are the principal forces, but the inertia, dynamic and centrifugal forces become considerable at higher speeds.

The gas pressure and inertia forces of the reciprocating parts result in a net force on the piston. The net result is a force along the connecting rod which resolves itself from the turning effort, or torque, on the crankshaft.
Determination of Horizontal Permeability Through a Probability Neural Network Approach
Authors: Soares L. , Ribeiro T. , Alves F. , Pereira M. J.
Published: December 2007

The main objective of this study is to present an alternative methodology based on the Probability Neural Network (PNN) formalism to estimate and further predict the permeability values in any location of a 3D grid of a reservoir model. An experimental data set containing measurements of log porosity, true vertical depth, transitive time and lithologies at well locations, was used for training the PNN. Afterwards, the trained PNN is applied to the wells where does not exist core information, but logs. The permeability values estimated by PNN in the wells are used to simulate the permeability at all spatial locations of the reservoir. This methodology was applied to experimental data from a reservoir located at West Africa with encouraging results.
Development of a Mathematical Model for Circulating pressures in Horizontal Well Killing Operations
Authors: Muthu Kumar J. , Sarma Dipen
Published: December 2007

The Wait & Weight method is one of the well killing techniques used extensively all over the world. To explain briefly, it is a constant bottom hole pressure (BHP) method of circulating the kick out while pumping a heavier kill mud into the well to replace the original mud which was in the well when the kick occurred. This requires that a certain circulating pressure versus pump strokes schedule must be maintained while pumping the kill mud, to keep the formation pressure equally balanced to prevent additional influx into the well. This pressure schedule helps to pre-determine the amount of circulating pressure that must be maintained at the drill pipe pressure gauge at any time when the kill mud is traveling from surface to bit. The standard methodology used for calculating the pressure schedule in vertical wells, assumes a linear relationship between the circulating pressure and the volume of kill mud pumped. If the same method is used in a deviated or horizontal wells, serious problems may occur. This includes over pressuring the formation which may lead to loss circulation, more complications in well control and or loss of well and its production.
Evaluation of the Corrosion Caused by Elevator and Spider Marks on C.R.A.-Pipe Comparing Conventional Inserts and a New Gripping System
Authors: Kinzel Holger , Tai P. T. , Büttner Kurt
Published: December 2007

Under a corrosive downhole environment, the completion of a well might be damaged if no precautions are taken. Pipe made of corrosion resistant alloys (C.R.A.) is used to minimize corrosion. An analysis of various corrosion mechanisms shows that the surface integrity is an important factor for corrosion prevention.

Conventional spider and elevator inserts cause die marks that support corrosion. A new developed gripping system distributes the required load equally onto a large number of small peaks, minimizing the indentation of each single peak.

Electrochemical investigations, the measurement of the surface indentations and microscopic analysis compare the effect of conventional dies and the new gripping system on C.R.A.-pipe.

Using the new gripping system, the surface integrity is not damaged and the corrosion potential is virtually eliminated.
Bringing Convergence to Well Control Training in Asia-Pacific
Authors: Kreeft G. J.
Published: December 2007

This paper will examine to what extent policy convergence with relation to well control is occurring in Vietnam, Thailand, Malaysia and Indonesia. The inspiration of this comparative analysis is based on a panel discussion held at the IADC 1995 Asia Pacific Well Control Conference held in Jakarta, and for which the author was the moderator.

The study will examine present well control training, its development, and future institutional development in Indonesia, Malaysia, Thailand and Vietnam.

The development of well control training guidelines in the Asia-Pacific Region will also be examined in the context of international development, i.e. IADC's WellCAP programme, IWCF, and bilateral developments in Asian-Pacific countries.
An Incentive Drilling Experience 1992-1996
Authors: Wee S.B. , van Dijk R.A.
Published: December 2007

Application of Incentive Contracting (IC) principles to the Drilling Operations in SSB/SSPC has resulted in the most significant improvement in operational and economic performance since many years. After four years of going through the learning curves, millions of dollars have been saved, not in the least because the service contractor fraternity has shown their commitment, without which the benefits would never have materialised. This article describes the development and implementation of these contracts in a restrictive contracting environment.

Introduction

Following many years of letting "dayrate" contracts for the entire range of drilling services in SSB/SSPC, the lack of incentive for the contractors to improve, significantly widened the gap between their performance and capabilities. This was aggravated by SSB/SSPC drilling staff assuming the exclusive leading role from well design to the execution phase inclusive. Upon full appreciation of the opportunities for improvement in the early 90's, SSB/SSPC drilling staff initiated the development and application of incentive conditions to their contracts. The basis was, that contractors could make monetary gains by performing sets of operations better than pre-defined targets. The challenge was, very much like in the "footage" type contracts of the past, to create a contractual situation that aligned the drilling and service contractors' goals with those of SSB/SSPC, albeit without the risks of the past. Due to HSE and Quality matters not being as much appreciated in the old days, many accidents occurred and many barrels of oil were rendered irrecoverable as a result of "rushed" operations. The "Drilling In The Nineties" (Ref. 1) type Incentive Contracts (IC's) that were developed over the past four years in SSB/SSPC however, link flexibility with HSE and Quality control to ensure history's downside does not repeat itself.

Originally instilled as a means to improve drilling performance by promoting faster execution only, IC turned out to be a "winner" in many more ways. Despite the "Production Sharing Contract" (PSC) environment and its contractual constraints under which Shell Upstream operates in Malaysia, application of IC's has actually led to a semi-integration of many services. The added value of integration lies in the continuous challenge from the team members in search for improvements to their respective share of the operations. The major drawback of contractual constraints has proven to be of lesser importance if the right mindset can be created, in which contractors can de-couple operational control from full contractual control.

Incentive contracts have now been used for four years on four large offshore development drilling campaigns and applied to four different drilling contractors and just as many rigs. Over that period, the incentive contracts have been refined and simplified and their scope has expanded to include almost all drilling, completion and workover activities.
Determination of Pressure Dependent Leakoff and its Effect on Fracture Geometry
Authors: Barree R. D. , Mukherjee H.
Published: December 2007

The effects of natural fissure opening, or pressure dependent leakoff, on the pressure behavior observed during fracturing are significant. Previous work has suggested that this behavior can be identified from pressure diagnostic plots during pumping, or from pressure falloff analysis. However, these techniques lead to ambiguous conclusions regarding the magnitude, and even existence, of pressure dependent leakoff. This paper presents a method of pressure falloff analysis which removes this ambiguity and allows an accurate determination of the magnitude of pressure dependent leakoff. The effects of fracture tip extension and recession, height recession, and transient flow in the fracture are also identified. The effect of pressure dependent fracture compliance, which has not been previously published, is also described.
Logging While Fishing: An Alternate Method to Cut and Thread Fishing
Authors: Tollefsen Ed , Crary Steve , Flores Bill , Hashem Mohamed N. , Roeterink Rene W.A.
Published: December 2007

New technology has been introduced to allow completion of the wireline logging program after the tool string has become lodged in the wellbore. Charges associated with extracting a stuck tool are substantial. These charges result from the nonproductive time during the fishing trip, an associated wiper trip, and re-logging the well. The ability to continue the logging program while retrieving the logging string from the wellbore is needed.

Logging While Fishing (LWF) is a hybrid of existing technologies combined with a new sub capable of severing a cable remotely. This new method is comprised of cut and thread fishing, drillpipe conveyed logging, and bridled tool techniques. Utilizing these techniques it is possible to complete wireline logging operations while removing a stuck tool from the wellbore.

Compleling logging operations using this hybrid method will save operating companies time and money. Other benefits, depending on the situation, include reduced fishing time and an increased level of safety. This application has been demonstrated on jobs in the Gulf of Mexico, North Sea, Venezuela, and Southeast Asia.
3-D Architecture Modeling Using High-Resolution Seismic Data and Sparse Well Control: Example from the Mars "Pink" Reservoir, Mississippi Canyon Area, Gulf of Mexico
Authors: Chapin M. A. , Tiller G. M. , Mahaffie M. J.
Published: December 2007

Economic considerations of the deep-water turbidlte play, in the Gulf of Mexico and elsewhere, require large reservoir volumes to be drained by relatively few, very expensive wells. Deep-water development projects to date have been planned on the basis of high-quality 3-D seismic data and sparse well control. The link between 3-D seismic, well control, and the 3-D geological and reservoir architecture model are demonstrated here for Pliocene turbldite sands of the "Pink" reservoir, Prospect Mars, Mississippi Canyon Areas 763 and 807, Gulf of Mexico. This information was used to better understand potential reservoir compartments for development well planning.
When Do Drilling Alliances Add Value? The Alliance Value Model
Authors: Brett J.F. , Craig V.B. , Wadsworth D.B. , Pile K.E. , Brett K.V.
Published: December 2007

A recent GRI report details three previously unstudied aspects of alliances: specific measurable factors that improve alliance success, how a successful alliance should be structured, and when an alliance makes economic sense. The most innovative tool to emerge from the report, the Alliance Value Model, addresses the third aspect.

The theory behind the Alliance Value Model is that the long-term viability of any drilling relationship hinges on its ability to create real value and achieve stability. Based upon the report's findings, the most effective way to form such an alliance is through a detailed description and integration of the technical processes involved. This new type of process-driven alliance is characterized by a value chain which links together a common set of technical processes, mutually defined bottomline goals, and shared benefits.

Building a process-driven alliance requires time and people and therefore has an associated cost. The real value generated by an alliance must exceed this start-up cost. The Alliance Value Model computes the net present value (NPV) of the cash flows for four different operating arrangements:Business As Usual (conventional competitive bidding process),Process-Driven Alliance (linking technical processes to accelerate production and reduce expenses),Incentivized Process-Driven Alliance (linked technical processes with performance incentives to promote stability), andNo Drill Case (primarily used to gauge the market value of services).

These arrangements test different degrees of process integration between an operator and its suppliers. They can also help determine if the alliance can add enough value to exceed startup costs and if the relationship will be stable. Each partner can test the impact of the relational structure on its own profitability. When an alliance is warranted, all participants can benefit from real value generated in a stable relationship. However, relationships that focus on commercial terms, instead of on process linking, may be playing a zero-sum, no-win game.

Background and Statement of Problem

The Gas Research Institute (GRI) recently completed a study which investigates the link (if any) between drilling alliances and improved drilling performance. The study goal is to discover the circumstances in which alliances are most likely to increase the industry's total system efficiency, thereby increasing the viability of marginal reserves. If some degree of success were identified, the study was to focus on identifying the critical factors for success and determining the circumstances under which an alliance is warranted.

To answer these questions, the GRI study focused on three specific goals:Identify the critical factors for alliance success. Where should drilling organizations focus efforts?

P. 51
NORM Waste Disposal Methods: Technology, Risk and Liability
Authors: Marinello S. A. , Lyon F. L. , Ballantine W. T.
Published: December 2007

Disposal of non-hazardous oilfield waste (NOW) containing naturally occurring radioactive material (NORM) is a critical cost consideration within industry. Depending on activity levels, onsite disposal of NORM waste may be possible through onsite landspreading, injection and/or encapsulation during P & A work or, rarely, injection into permitted Class II wells. Some companies have investigated the processing and injection of slurried solid waste for disposal into depleted production boreholes. In most cases, this would require controlled fracturing, classic, dissolution or both, in order to provide disposal pathways and storage volume. Most state regulatory agencies will not consider such action due to federal regulations and the perceived potential for "uncontrolled" fractures allowing direct or indirect contamination of USDW aquifers.

Present permitted offsite disposal alternatives include surface disposal facilities; landfilling at sites in Washington and Utah or landtreating to below 5 pCi/g in Louisiana, or subsurface injection into Class II wells. Injection takes place after chelating and solubilizing or slurrying NORM solids. Injection as a slurried solid waste at a licensed commercial facility in Texas has become the dominant disposal method for oilfield waste containing NORM. Upfront processing and disposal costs and potential for future liability with each method of disposal is presented as related to both the NORM waste itself and to associated processed oil and gas wastes.

For (relatively) high activity NORM from the oilfield (>6,000 pCi/g 226Ra activity and/or 30,000 pCi/g total specific activity), near surface storage/disposal is the only present option. For lower activity levels, the choice is between near surface and underground disposal. Potential liability appears to be limited with injection of non-solubilized slurried waste. Real onsite disposal cost evaluations must consider well modifications, processing and closure charges. Processing and transport costs define the upfront costs for offsite disposal and are competitive across the board. An assessment of future liability costs related to NORM and associated oilfield wastes is necessary to determine the best disposal method.
Bifurcation Analyses of Water Out Mechanisms in Heterogeneous Reservoirs
Authors: Luan Zhi-an
Published: December 2007

Based on a geostatistical model and an abstract model new ideas on water out mechanisms of heterogeneous reservoirs are presented. It shows that the strong heterogeneous reservoirs are initial imperfect, so that long period prediction of dynamical behavior is impractical. Unsuitable water drive perturbations will bring the reservoir with high permeability variation rapidly into attractor set that have a low recovery. The further movement and shrinkage of attractors are done only by using physics-hydrodynamic methods.

Models of Water Out

In heterogeneous reservoirs practical every formation is stratified to some extent; that is to say, it contains layers of differing permeability ki(x),i=1,2,…,n. To illustrate the effect of such stratification on water/oil ratio, we construct a simple geostatistical model in which permeability of any layer is random variable and permeability of specific layers will take on constants equal to or higher k. The probability distribution function F(k) is the thickness ratio of these specific layers to all layers, and it can be defined by = F'(k)dk = f(k)dk where h = formation thickness, h = sum thickness of the specific layers (permeability>k), f(k)= distribution density of permeability k. It will be assumed that there is no vertical communication between the layers, except through the well bore. Considering l-D piston-like displacement we obtain the global water/oil ratio R. In formulae 1-length of formation, k* is permeability of a layer in which the water breaks into the bottom of the wellbore From the Eq. 1, firstly, note that fact:

the larger o / w, the more viscous the oil, the more rapidly will the water/oil ratio increase. Secondly, note that this increase will also depend on the standard deviation of the formation permeability. The larger the coefficient of variation, the more rapidly will the breakthrough occur. Once the water has flooded a high permeable stringer, it has established a "short - circuit" of least flow resistance and led a low sweep efficiency. It should be indicated that the water accumulation near the oil well bore will be preferable imbibed into less permeable layers. Therefore, if the medium is water (or oil)-wet, the relative permeability of oil phase near a well bore may decrease dramatically with cumulative production, which will bring this reservoir rapidly into the higher water out. A typical change of water saturation is shown on the right-hand portion of Fig. 1. The characterization of area sweep models is similar to that of the above vertical sweep model.

As an extreme case, reservoirs having fracture-matrix are both area heterogeneity and vertical heterogeneity. For real reservoirs, there is no a realistic geostatistical model.

Water Out Mechanisms and Attractors

Buckley-Leverett (B-L) equation is a nonlinear evolution equation which contains nonlinear convective and capillary dissipative terms. P. 811
An Application Utilizing Horizontal Re-entries Versus Water-flooding for Depleting a Mid-Life Niagaran Reef
Authors: Pieters D. A. , Pearce L. A.
Published: December 2007

Waterflooding has been the preferred secondary recovery technique for mid-life Michigan Niagaran reefs that were large enough to economically warrant it. Since these pinnacle reefs average 50-550 acres, the success in waterflooding such a limited space has been a hit or miss proposition depending on the pinpoint accuracy in locating injector and producer. This paper presents a case history for the Colfax 25 reef where five horizontal drainholes were positioned across the field in a pattern to access and drain all areas of the reservoir. This particular reef was chosen based on identified incremental reserves, areal extent and on past production history which displayed reservoir characteristics that were favorable for horizontal wells. The application was tremendously successful. Production in all wells doubled as gas oil ratios were significantly reduced. Start-up costs were slightly below those of a conventional water flood and operating costs were substantially lower than would be incurred for a waterflood.
Mobility of Polymer Solutions in Porous Media
Authors: Ershaghi Iraj , Handy Lyman L.
Published: December 2007

Over the past few years, considerable interest has developed in the use of certain synthetic polymers as mobility improvement additives in waterflooding. It has been argued that these compounds, when added in very low concentrations to the injection water, exhibit extraordinary flow resistance and reduce the injection water mobility. The mechanism by which these polymers cause excessive flow resistance is not yet clearly defined, however.

In this study flow of polymers through porous media was investigated computing polymer porous media was investigated computing polymer solution mobilities within porous media from measurements of pressures as a function of distance along linear core samples. Determination of pressure gradients within the cores has eliminated effects resulting from plugging of the inlet face. Filtered and unfiltered polymer solutions were used.

In general, filtered polymer solutions gave better penetration of the pore space. With unfiltered polymer solutions substantial filtration occurred at the inlet end of consolidated cores. Little or no polymer penetrated to the effluent end. Water mobilities calculated between pressure taps were essentially equal to that of brine. Filtered polymers, however, did show brine mobility reduction between pressure taps. With continued injection the water mobility continued to decrease and did not appear to approach a steady state short of plugging. This plugging effect was substantiated by polymer plugging effect was substantiated by polymer concentration measured for the effluent fluid. These concentrations went through a maximum and then decreased to zero as the polymer plugging became complete. The results indicated accumulated in-depth polymer plugging of the porous medium.

Although the results do confirm in-depth reduction of water mobilities, they also suggest that the deep penetration of reservoir rocks required in waterflooding would not be likely to occur. The residual effect appears to be an unsteady state effect which leads to complete plugging of moderate to low permeability plugging of moderate to low permeability sandstones with continued injection. The polymers do appear to have potentials in sealing thief zones and thereby improving vertical sweep efficiency.

Introduction

Oil recovery by waterflooding can be effectively improved by reducing the mobility ratio between the injected water and the displaced oil. This has been well substantiated by both theoretical and experimental studies.
A Study of Oil Recovery by In-Situ Combustion with the Addition of Water
Authors: Alderman John H. , Osoba J.S.
Published: December 2007

The object of this work was to improve the forward combustion process by injecting water simultaneously with air. One of the methods used to recover oil from underground reservoirs that has gained interest in recent years is in-situ combustion. This process involves ignition of the oil in reservoir rock and the propagation of the resultant combustion zone propagation of the resultant combustion zone toward producing wells by the injection of air. However, at the present time this method has enjoyed only marginal economic success in a limited number of applications.

To study this process, a combustion tube was packed with oil, water, sand and clay. Combustion was initiated and propagated down the tube by the injection of air. In three runs water was injected with the air to study its effect. The produced gas and liquids were measured and analyzed. The temperature and rate of advance of the combustion front were also measured. Pressures at the inlet, outlet and points along the tube were measured throughout points along the tube were measured throughout the run.

It was found that adding water to the injected air effected the oil recovery. In all cases where water was injected, oil recovery increased. The rate of oil recovery also increased. More efficient utilization of heat also took place because of the movement of heat from behind the combustion zone to the oil zone ahead of the combustion zone.

Introduction

Among the methods to recover oil from underground reservoirs that have gained interest in recent years are those involving the application of heat to the reservoir. The use of heat to increase production rate and recovery is not new, however. Shortly after the completion of the Drake well in 1859, steam was used to melt paraffin from the wellbore and increase the rate of paraffin from the wellbore and increase the rate of oil production. In 1935, the Russians were conducting experiments to recover more oil by a process they called crude oil gasification. This process they called crude oil gasification. This work involved moving heat outward from a wellbore into a formation and was the forerunner of an oil-recovery mechanism known today as in-situ combustion.

In-situ combustion has, however, met with only marginal economic success in displacing oil from reservoir rock and has found limited application. One reason for this has been poor utilization of the generated heat. Most of the heat is left in the burned portion of the reservoir.

One advantage gained from the application of heat to a reservoir is based on reduction of crude oil viscosity at the higher temperature. For the lower gravity oils this is a substantial decrease.
Cost Control & Development And Production Of Egyptian Western Desert Marginal Fields
Authors: Pretto Lorenzo , Ghareeb Mohamed
Published: December 2007

The various crises which affected our oil industry have emphasized the need for detailed control of expenditure for development and production of oil small discoveries. Fields with recoverable reserves of about five MMSTB are classified by EGPC as marginal fields. In the past such discoveries in Egypt were not considered economic. A few years ago EGPC, through its operating companies, introduced and adopted new management systems that many of international major companies were utilizing. The following approaches are used to cut the operating costs:-EGPC supporting the operating companies by all available technical information for drilling production and processing operations.Facilities sharing.Existing pipeline network utilization in developing western desert marginal oil fields.Using early production system to evaluate the field in order to minimize the capital cost.

This paper will provide and discuss Agiba experience in developing and producing marginal fields. As case histories this paper will present Ras El-hekma and Zarif fields development and production achieved by Agiba staff challenging effort.

Introduction

Several discoveries in Egypt, which were not considered economic at the time of discovery, started to produce in the past few years. This change happened because a non traditional approach was followed in developing and operating such fields, turning them into profitable projects. The unconventional methods to develop marginal fields, mainly utilized to cut developing and operating costs are:–utilization of rented and/or shared existing facilities–utilization of existing pipelines–use of existing exporting facilities–company work by challenging objectives : high commitment and motivation to find innovative ways of applying new or existing technology to achieve challenging results.

This paper gives better insights into Agiba's potentiality and capability in developing fields / reserves that were not economically attractive in the past.

Example of these development schemes that were recently achieved by either technology application or new innovation are:–Zarif field–Ras El-hekma field

In the near future, end of November, another marginal field, El Faras, will start up. Figure (1) shows western desert location.

P. 309
Waste Water Reclamation for Steam Generator Feed Kern River Field, California
Authors: Smith M.L.
Published: December 2007

This report is a summary of a program of comprehensive study, testing, pilot work, and the operational development of a system which reclaims fresh produced water for use as steam generator feedwater. This system is unique because of:

(1) The extremely high quality of the effluent - essentially 0 PPM suspended solids of which oil is the primary contaminant.

(2) The capacity of the system - initial design 200,000 BPD - now increased to 250,000 BPD.

(3) A design which guarantees continuous throughput on a 24-hour basis.

(4) The reclamation which is accomplished at a cost per barrel competitive with other fresh water sources.

The report will discuss the other methods of reclamation tested, the engineering considerations used in the design of the system, and operating problems encountered in the initial operation. The system which has been in operation for three years started at a capacity of 100,000 BPD. It is presently treating in excess of 200,000 BPD and will reach 250,000 BPD by the end of this year.

Introduction

The Getty Oil Company thermal program in the Kern River Field is completely dependent on an adequate and reliable supply of steam generator feedwater. in the summer of 1966, generator feedwater requirements of 100,000 BPD were supplied by eight water wells. This well water was softened and distributed to the field at a company facility called the G and W softening plant. Increasing feedwater requirements, a rapidly dropping water table, and more stringent requirements by the State Water Pollution Control Board on the disposal of field waste water made it apparent that a waste water reclamation system should be investigated. If successful, this system would serve the dual purpose of providing an independent supply for the necessary feedwater requirements and, at the same time, solve the problem of waste water disposal. problem of waste water disposal.
Full Field Dual Porosity Modelling of a Complex Fractured Chalk Oil Reservoir Subject to both Gas and Water Injection
Authors: Conway P.I. , Damm M. , Andersen P.M.
Published: December 2007

The Gorm Field A-block reservoir is a tight chalk oil reservoir which has been on production since 1981. The reservoir contains an interconnected tectonic fracture network at the crest of a domal structure, the flanks of the structure being non-fractured. Reservoir pressure has initially been supported by gas injection which was installed for gas disposal. Water injection was initiated in 1989.

An integrated production development study has been performed in which dual porosity reservoir simulation modelling has been a central activity. A key task has been to identify the dominant recovery mechanism(s) to assist in selection of an optimal further development scheme. A conceptual simulation model comprising a simple 1-dimensional dual porosity stack model, and a finely gridded 3-dimensional full block dual porosity simulation model have been constructed. The models incorporate capillary continuity, gas-oil re-imbibition effects, and calculate the contribution to oil recovery from pressure differentials across matrix blocks due to dynamic pressure gradients in the fracture system. In addition, capillary pressure and relative permeability hysteresis have been incorporated based on SCAL data.

Field historical production and injection performance have been successfully matched using the full block model, including the observed response in production wells to gas and water injection, and pressure gradients within the reservoir observed from RFT data.

The calibrated models subsequently have been used to demonstrate that;–gas-oil gravity drainage has been slowed by reimbibition effects and has had a limited effect on oil recovery–significant oil recovery was attributable to viscous gradients in the fracture system as a result of gas injection. However, due to recycling of large volumes of gas through the fracture system, this was a less efficient recovery mechanism than could have been achieved by water injection.–oil recovery due to natural water influx or water injection had been predominantly via spontaneous imbibition to date, and remaining movable oil could be best activated by increasing viscous gradients by stepping up flank and basal water flooding.–gas relative permeability hysteresis has caused significant volumes of free gas to be trapped in the crest of the reservoir

Gas injection has subsequently been discontinued and water injection extended. The drilling of three production wells and one injection well and the provision of greater water injection capacity was predicted to lead to a doubling of field oil rate due to the decline in producing GOR, and an increase in ultimate oil recovery from 33% to 44%. The early field response has supported these predictions.

Introduction

The Gorm field, located in the Danish Sector of the North Sea, was discovered in 1971 by the N-1X exploration well.

P. 497
Miscible Waterflooding Using a Phosphate Ester Solubilizer
Authors: Halbert W.G. , Inks Clyde G.
Published: December 2007

A simple micellar solution or microemulsion has been tested for its oil displacement capabilities in a sandstone core. The micellar solution was prepared using crude oil, water and a phosphate prepared using crude oil, water and a phosphate ester surfactant.

Phase studies at 74 degrees F showed that a micellar solution existed when the phosphate ester surfactant concentration was 4 to 8 percent by volume or greater in a sour crude oil and water system. Similar concentration requirements were exhibited by a sweet crude oil-water system. Tests at elevated temperatures showed that the microemulsions tended to degrade as temperature was increased. Partial and total neutralization of the acid surfactant improved the microemulsions tolerance of higher temperatures.

Oil displacement tests showed that the micellar solution employed was capable of displacing 90 percent of the core's oil saturation. Slug floods of 30 percent PV and larger yielded an oil displacement percent PV and larger yielded an oil displacement efficiency of 90 percent also. Water-driven slugs were employed. Displacement efficiencies exhibited by oil-rich and water-rich micellar solutions were slightly different. These differences are explored via dilution arguments.

Introduction

Numerous patents and publications have appeared regarding the use of micellar solutions or microemulsions for secondary recovery of oil and the stimulation of water injection wells. These papers report the use of certain petroleum sulfonates as the solubilizing agent. The excellent capabilities of the petroleum sulfonates has been demonstrated.

The purpose of this study was to explore the oil displacement merits and certain phase characteristics presented by a different solubilizer - a mono substituted presented by a different solubilizer - a mono substituted ortho phosphate ester. The surfactant employed is manufactured by BASF Wyandotte Corp. and marketed as KLEARFAC AA-420. This surfactant is an anionic, biodegradable liquid that exhibits solubilizing properties within a broad pH spectrum 17 Used primarily in metal cleaning and textile processing, its capability of recovering oil has not been previously studied.

Preliminary phase behavior studies showed that KLEARFAC AA-420 was an excellent solubilizer of crude oil and water. This characteristic prompted a series of oil displacement tests plus further phase behavior tests at elevated temperatures.
The Three-State Model Of Pore Fluid Distribution
Authors: Chen Yongsheng , Liu Zhenyu , Dewu Fu
Published: December 2007

This paper, which uses large amount of data, discusses the wettability of formations and reservoirs and its characteristics by analyzing the surface tension and surface electrostatic force of different rock minerals and pore fluids, the effect of preferential wetting and preferential adsorption on reservoir wettability, and the change of reservoir wettability after water flooding. On the basis of the above discussion, three-state model of pore fluid distribution are divided into three types.

Surface Dynamic Nature of Rock - Forming Minerals, Clay and Fluids

i. Rock-forming minerals

Liquids and solids have surface tension. All the experimental materials indicate that solids have larger surface tension than liquids. The mineral grains which form reservoirs are made up of non-uniform ions with different electric properties. All the ions on the surfaces of the grains have an asymmetrically electric field as well as an asymmetrically gravitational field. These asymmetrical fields make the grain surfaces form a weak electromagnetic field. Now we shall analyze the commonest surface layer.

i) Quartz

Take the commonest - quartz for example. The crystal structure of - quartz is shown in Fig. 1. It is usually known as silicon-oxygen tetrahedron. From this we can know:The tetrahedron surface is oxygenThe proportion between silicon and oxygen in SiO2 is 1:2.Because of the above characteristics of the surface structure, the quartz surface is made to be a negative electric field. It is proved by calculation that the force of unit negative charge at the distance b (0) from the surface of - quartz is(1)where - diameter of O2 - f - Coulomb factore - Charge of an electron

ii) Feldspar

In the gap of the frame structure formed by silicon-oxygen tetrahedrons and aluminium-oxygen tetrahedrons, these are full of potassium or sodium ions sometimes Calcium or barium ions (See Fig. 2). Such crystal characteristics, in addition to the actions of potassium ions, decrease the negative field intensity of the crystal surface and make the negative field intensity of Feldspar surface less than that of quartz's.

Calcite also exists in rock-forming materials of sandstone reservoirs. Analyzing of crystal structure, the polarity of calcite is smaller than feldspar's. Since water is a molecule with strong polarity, general speaking minerals which have strong field intensity have strong hydrophilic nature. Daqing Oilfield made an experiment by use of a crystal of feldspar and quartz and the same quantity of oil and water. The result is that the contact angle of oil on the quartz chip is smaller than that on the feldspar's. This indicates that quartz has a stronger hydrophilic nature than feldspar.

ii. Fluids

The fluids in the pore space are usually oil, air and water.

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Application of an Integrated Single Well Model to Drawdown and Buildup Analysis of Production from Commingled Zones
Authors: Almehaideb R. A.
Published: December 2007

The problem of designing and analyzing well tests for wells producing from multiple zones through the same production string is often complicated by the interaction between the different layers. Often, measurements of both downhole rates vs. depth in addition to downhole pressure is required so as to ascertain how much rate is coming from each layer in order to analyze the response of each layer separately. A complicating factor comes in if the layers are communicating, which may significantly reduce the accuracy of available analytical methods.

This paper describes new applications of a recently developed integrated single well model (ISWM) that couples equations describing dynamic wellbore flow with ones describing transient reservoir flow. This coupling allows the user to assign production, injection, and shut-in of wells at the surface point, where the valves are physically located, instead of downhole for conventional reservoir simulators. The wellbore flow is handled by use of the Bernoulli equation including friction and kinetic contributions to pressure drop.

Another feature of this model is the use of the full rate equation for gas flow in the reservoir, including the inertial-turbulent (forcheimer) term, in order to handle the rate-dependent skin in addition to mechanical skin at the wells. Reservoir and wellbore equations are solved simultaneously using the fully implicit Newton method.

Applications for this model include determining the dynamic wellbore pressure drop versus time for both single phase oil or gas, and multiphase production and shut-in in vertical and deviated wells, and the resultant change in production rates at the wellbore sandface with time. This feature enables the engineer to simulate the actual flow rate coming from each layer and the resultant reservoir response as measured downhole from a pressure recording tool. The degree to which crossflow affects pressure response can also be measured. Examples describing how one can use the model to better design well tests i n commingled formations are also included.
Maximising Well Potential: An Integrated Approach
Authors: Walters N.S.
Published: December 2007

The paper summarises the strategy and methodology employed to maximise well productivity and minimise formation damage during the well construction process for the Wanaea and Cossack projects. Actual performance against expectations and targets is reconciled. The outcome has been oil wells with lower than expected skins and as a direct consequence, aggregate well potential is in excess of nameplate process capacity. The incremental cost associated with achieving the better than expected well potentials has been small due to the methodology employed, but the incremental value is high.

The strategy adopted can be summarised as:–Where are we now?–What is possible?–How do we get there?

rather than the incremental methodology of 'how can we improve'.

This was found to be a very powerful strategy. The methodology used to implement this strategy is described, which included a life cycle approach to completion design and a laboratory based programme to assess various aspects of the drilling and completion processes on productivity. The application of 'fit for purpose' technology; including a novel horizontal completion design and use of long (100m) wireline conveyed perforating guns is also described.

Introduction

The Wanaea and Cossack oil fields are located in some 80m of water approximately 100km offshore North Western Australia. The two fields are being developed in parallel using subsea wells tied back via manifolds and flexible flowlines to an FPSO with a design life of 25 yrs; Reference Figure 1. Well construction activities occurred between July 1994 and February 1995, with production start-up in November 1995. Maximising Net Present Value (NPV) over the life-cycle of the well requires achieving the correct balance between:–Initial CAPEX (ie. well construction costs);–Tubing size vis a vis well productivity (initial production rate, forecast production profiles);–Well reliability and intervention costs (surveys, workovers etc.); and–Installing the appropriate degree of flexibility to cater for reservoir performance uncertainties.

The prime cost driver for the process of well construction was identified as rig time and therefore reducing rig time became the primary focus for cost reduction. However, well productivity was identified as potentially having the most significant impact on Net Present Value (NPV) over field life and therefore any proposed cost reduction was weighed against potential impact on well productivity.

This paper focuses on the application of the above strategy on well productivity and completion design and summarises the solutions adopted. The development and application of the philosophy and the necessary cultural climate is fully described in Reference 1.

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