bluuebunny/crossref_metadata_2025 huggingface dataset:
1988 Summary Report SPE Five Year Review Of Engineering Manpower
Authors: Calhoun John C.
Published: December 2007

Eleven responses were received to the survey questionaire, of which nine contained data sufficiently complete for comparative analysis. One responding company reported less than ten engineering employees; one fell in the category of 10–20 engineering employees; one in the 40–50 range of engineering employees; one in the range of 100–120; two in the range of 300–500;and three in the range of 500 or more. Table 1 shows the five year summary of all respondents for total engineers employed at year end; degreed petroleum engineers employed at year end; total number of engineering hires during the year from universities; total number of degreed petroleum engineering hires during the year from universities; and total number of engineering hires during the year from sources other than the campuses. The high year for engineering employment was 1984, not only for all engineers but also for degreed petroleum engineers. In the 1984–1987 interval, employment of all engineers dropped 21.2% and employment of degreed petroleum engineers dropped 17.3%. The percentage of petroleum engineers in the total engineering work force increased from 62 to 65 over the five year period 1983 to 1987.
Alternatives for Draining Tight Naturally Fractured Gas Reservoirs: Horizontal Hole Drilling vs. Massive Hydraulic Fracturing
Authors: van Kruysdijk C. P. J. W. , Niko H.
Published: December 2007

Tight gas reservoirs with matrix permeabilities in the microdarcy range sometimes contain zones of natural fractures with relatively high permeabilities. The development of these reservoirs requires great care in that it is essential to connect the wells with the natural fracture system in order to ensure economic well productivities.

To assess the feasibility of developing such reservoirs, a study was undertaken to investigate the relative attractiveness of connecting a well to a vertical zone of high permeability either by a horizontal hole or by a massive hydraulic fracture (MHF). The first phase of the work assumed single-phase compressible flow and utilised Green's function theory to derive the transient pressure response in such complex situations. The results indicate that a horizontal hole draining a natural fracture zone compares well with connecting the well to the naturally fractured zone by a MHF, particularly in the case of short MHFs. The calculations also resulted in new principles for the interpretation of well tests for the two situations described above. For example, interpretation of the formation linear flow period when there are multiple fractures indicates fracture areas that are larger than the area of the MHF.

The second phase involved numerical simulation, with mobile water both in the matrix and in the fracture systems taken into account. The results, which agree qualitatively with those of analytical methods, indicate under which conditions coning or cusping of water from the fractures into the well perforations might be expected.
Transoil Technology for Heavy Oil Transportation: Results of Field Trials at Wolf Lake
Authors: Stockwell A. , Sit S. P. , Hardy W. A.
Published: December 2007

Since 1982, BP Research International has been investigating the suitability of oil-in-water emulsion technology for the transportation of heavy oils and bitumens as part of a collaborative research agreement with Intevep S.A., an affiliate of Petroleos de Venezuela S.A.

During the course of this work, in 1983, a new method for the preparation of stable oil-in-water emulsions was discovered. Patent applications for the process have been filed in appropriate countries.

Encouraged by the results of a substantial programme of laboratory and small-scale pilot plant research at the Sunbury Research Centre of BP Research International, a Joint Venture was established in 1987 between BP Canada, the Alberta Energy Company and BP Canadian Holdings to develop and demonstrate TRANSOIL technology at Wolf Lake, Alberta, Canada.

The development programme has recently been completed in trials designed to evaluate the scale-up of the TRANSOIL emulsification process, the storage properties of the emulsions produced, their transportation characteristics and their ultimate demulsification.

This paper describes the background to the technology, the facilities used and the results obtained during the trials.
HESPER: An Expert System for Petrophysical Formation Evaluation
Authors: Peveraro R. C. A. , Lee J. A.
Published: December 2007

A prototype expert system for formation evaluation is introduced and discussed, beginning with the rationale for its development, and presenting briefly qualitative assessments and tests of its performance.

The background and definition of petrophysical formation evaluation is clarified, and the specific geological frame of the Permian Southern Basin of the North Sea, in which the system operates, is presented, with indications of future developments.

The different modules of the system are discussed in some detail, and the interaction between modelling, advice-giving, and the user interface is clearly shown to be a crucial factor. Of particular importance is the ability of the system of presenting the reasons for its choice of solution in a clear text and in a user-intelligible fashion.

Tests and performance of the system are discussed from a qualitative viewpoint, rather than after rigorous benchmark tests. This is considered appropriate at this stage, since the system is by no means in its final configuration.

The conclusion has been reached by Britoil that the system has demonstrated that the application of expert systems design and technology to petrophysical formation evaluation is both feasible and desirable, and further development would therefore be beneficial.
Chemical Systems for the Control of Asphaltene Sludge During Oilwell Acidizing Treatments
Authors: Jacobs I. C.
Published: December 2007

A number of effects have recently been studied as they relate to sludging tendency including: acid type and strength, the use of reducing agents, amounts of Fe II and Fe III in test procedures, the use of mutual solvents and/or wetting agents, the use of iron chelants and/or extractants, and the effects of different acid corrosion inhibitors. Crudes tested and found to exhibit iron induced sludging included the Beaverhill Lake crudes of Western Canada as well as crudes from Alaska and California and San Andres and Smackover crudes from Texas and Mississippi, respectively. Testing techniques are discussed as well as additives response. The chemistry of iron extractant and anti-sludging/dispersant packages is reviewed.
Wettability Preferences of Minerals Used in Oil-Based Drilling Fluids
Authors: Cline J. T. , Teeters D. C. , Andersen M. A.
Published: December 2007

The wettability of typical drill solids and mud weighting agents in simple oil-based drilling fluids was studied with a newly developed dynamic Wilhelmy plate technique. Thin plates were cut from mineral specimens and used for wettability testing without polishing. The fluid systems studied were equilibrated brine with oils containing typical additives such as emulsifiers and organophilic clays. Thin plates of barite, hematite, quartz, marble and shale were moved through the air/oil and oil/brine interfaces while wetting forces were continuously measured in the advancing and receding directions.

Without added emulsifier, quartz and shale were usually preferentially water-wetting in mineral oils/brine. The oil-mud weighting agents - barite, hematite and marble - were oil-wetting when advancing from mineral oil into brine and water-wetting when receding from the brine. If these minerals were wet with water before wettability testing, they remained water—wet when immersed in oil. In an oil mud system, solid additives should not be wet with water before addition to an oil mud.

Wettability preferences of the minerals, including shale, were altered by diesel oils and by oil-mud additives. Diesel oils made the minerals oil-wet. The common oil-mud emulsifiers, such as tall oil soaps and polyamides, and organophilic clay caused the "dry" minerals to be strongly to moderately oil-wet and lowered the oil/brine interfacial tension. Excess emulsifier ensured that the solids in an oil mud remained oil-wet. But if the solids were initially wet with water, or if the oil-based mud became inverted (water-continuous), the water-wet solids clumped together and became difficult to revert to oil-wet. This troublesome problem occurs in field muds and is referred to as a "flipped" mud.

Wilhelmy plate wetting results were correlated to the wetting behavior of solids in emulsions by photomicroscopy such that observed water-wet solids were correlated to measured adhesion tension indicating water-wetting and vice versa.
Low-pH Ammonium Nitrate-Methanol Completion Fluid: A Promising Alternative for Calcareous, Argillaceous Sand Formations
Authors: Krilov Z. , Wojtanowicz A. K. , Langlinais J. P. , Dernikovic B.
Published: December 2007

The objective of this research was to formulate and examine a new completion fluid, a mixture of the ammonium nitrate and methanol. The potential applications for the fluid are completion and workover operations in calcareous, argillaceous sand reservoirs similar to the gas reservoirs located offshore Adriatic Sea. The new fluid becomes a promising alternative to the unsuccessfully-used, traditional chloride-type brines.

The concept of the new completion fluid was based on a combination of the clay-stabilizing effects of ammonium ions with the clay-inhibiting properties of alcohol at low pH values. The preliminary flow tests showed a lower level of permeability damage with the new fluid as compared to the conventional KCl, CaCl2 and NaCl brines.

In this study, various aspects of the new completion fluid's implementation were systematically evaluated. The evaluation procedure included (1) typical core floods (inflow tests that simulated well completion), (2) reversed core floods (backflow tests that simulated well production), (3) core floods at various levels of influent pH, and (4) corrosivity tests. The laboratory core floods were conducted on the reconstituted cores that were made of the unconsolidated core material from the gas reservoirs located offshore Adriatic Sea.

The study revealed superiority of the new completion fluid over the conventional brines, in both inflow and backflow core floods. Porosity development, caused by pore cleaning, was observed in the SEM microphotographs and in the effluents particle-size distributions.

There was a strong correlation between the reservoir rock permeability and the pH of the ammonium nitrate-methanol solution; for the alkaline solutions, permeability damage increased with increasing pH. However, for the acidic solutions the permeability improvement was observed, and it was inversely affected by pH (i.e. lower pH caused permeability increase).

When uninhibited, the new fluid appeared to be highly corrosive, particularly for a pH lower than four. However, the experiments with the corrosion inhibitor showed that for a pH between four and five the new fluid can be effectively inhibited so its corrosion rate will be below the maximum acceptable limit, 0.005 in./year.
Optimized Slurry Design for Salt Zone Cementations
Authors: van Kleef R. P. A. R.
Published: December 2007

The influence of salt content on the performance of saline cement slurries has been investigated with the objective of improving primary cementations through salt layers.

It is shown that the pumpability times of neat saline cement slurries under low-shear conditions (as encountered in the field) are virtually independent of salt content. Pumpability time and time of final set (onset of strength development) determined under these conditions are shorter than the API thickening time.

Salt introduced into a neat cement slurry by halite formation dissolution during the cementing operation has much less Of a retarding influence on pumpability time and time of final set than the same quantity of salt introduced into a slurry during mixing.

In dispersed slurries, medium to high salt contents cause excessive retardation of cement set. At low-shear conditions, pumpability times are about twice as long as those determined in API tests. As a consequence of this high shear sensitivity, the setting time of dispersed saline slurries cannot be controlled effectively in the field.

Core-flow tests show that salt is not eroded by cement Slurries. Salt dissolution occurs with non-saturated cement slurries, with the dissolution rate being clearly influenced by the state of fluid flow.

Salt is dissolved by non-saturated cements even after final set. This results in the formation of a micro-annulus at the salt/cement interface. Usually, the creep rate of the salt is sufficient to close the micro-annulus within a reasonable time, i.e. before the well is completed. If salt creep rates are expected to be insufficient to ensure zonal isolation, salt-saturated cement slurries should be used. In all other cases, the use of salt-free or low-salt-content cements is recommended. These slurries have been used successfully in many North Sea wells.
Extended Nozzles and Gauge Drilling Are Keys to Bit Design in Alwyn 17½
Authors: Delafon H. , Bannerman J.
Published: December 2007

TOTAL OIL MARINE pic, operator on behalf of an association of Total Oil Marine (33.3%) and Elf UK (66.6%) has been drilling the development wells of Alwyn North field in UK North Sea since early 1987. One of the most critical phases in this field is the 17½" phase. It is unusually deep and drilled with water based mud through abrasive and sticky formations. One key success has been the step by step improvement of 17½" rock bits in conjunction with the bit manufacturer.

This paper presents:

A constructive engineered approach used throughout the Alwyn project, where all bits were systematically recovered, photographed, thoroughly examined and cut into pieces to understand any possible wear mechanism.

The improvement in 17½" bits performances obtained between the first two wells (6 to 7 m/hr ROP - 100 to 150m metrage) and the sixteenth well (31 m/hr ROP - 800m metrage).

The main progression steps, each one being associated with a specific bit design.

The learning made on how to efficiently use extended nozzles in the field.

Problem 1 : Poor cutting evacuation at the bottom of the hole.

Problem 2 : Gauge drilling the "corner" of the hole, i.e. the transition area between the side and the front of the bottom hole.

Problem 3 : Hydraulic erosion inside the bit body.

Problem 4 : Hydraulic erosion inside the extended nozzles.

Problem 5 : Interference of directional drilling considerations.
Cleaning Deviated Holes: New Experimental and Theoretical Studies
Authors: Brown N. P. , Bern P. A. , Weaver A.
Published: December 2007

A number of studies have been carried out by other researchers into cleaning deviated holes. However, the results to date do not provide clear operational recommendations. A research programme that addresses hole cleaning is in progress using Field-scale equipment. Experimental results have been obtained from circulating water and HEC polymer-based pills. The experimental studies are complemented by mathematical modelling.

A comparison of the results from the inclined equipment show that not only is the transport of cuttings initiated at lower flow rates when water is circulated, but also the rate at which cuttings are removed is higher. The poorest removal rates generally occur with inclination angles in the region of 50 to 60 degrees. Predictions from the mathematical model are in reasonable agreement with the experimental data.
A Case History Review of the Effects of Drilling Fluids on Shale Stability in the Central Gulf of Mexico
Authors: Gilmore W. H. , Sanclemente J. B.
Published: December 2007

In 1987 Chevron conducted an experiment to obtain data which could be used to comparatively evaluate the ability of various mud systems to stabilize highly reactive shales and gumbos, such as those found in the U. S. Gulf Coast. The mud systems used in this study range from the commonly used chrome lignosulfonate system to polymer systems to variations of gypsum or lime systems.

In order to evaluate the ability of the various mud systems to stabilize the borehole, four-arm or six-arm caliper logs were run in the intervals of interest. The average borehole diameter was calculated from this caliper data. A program which calculates annular hydraulics was run on the data for each interval to determine if any of the observed washout could or should be attributed to hydraulic erosion. The average hole diameter was then used as a measure of borehole stability. The closer the average hole diameter was to the bit size, the more stabilizing the mud system.

The results were consistent with the findings of independent work performed at the same time. The commonly used chrome lignosulfonate mud had the highest amount of washout (139 - 179%). The muds containing only potassium hydroxide provided a hole with washout reduced to 0 - 10%. The other muds systems provided borehole with washouts ranging between 14 - 116%.

As a result of the experiment, the potassium hydroxide low lime graft copolymer lignosulfonate (GCPLS) system consistently provided the most gauge hole at a cost approximately equal to that of a chrome lignosulfonate mud. However, solids control was realized to be an absolute necessity if this system was to be run in a cost-effective manner. On one well where poor solids control had been identified, the mud cost was double that of other systems in which good solids control had been maintained.
Unleashing the Power of Steerable Systems
Authors: Whitten R. G. , Petrey P. A.
Published: December 2007

Since their introduction, steerable systems have captured a large share of the directional drilling market, accounting for almost 45% of directional wells drilled in the Gulf of Mexico in March of 19881. The wide acceptance of these drilling tools has been primarily due to the cost savings available from a reduction in the number of bottom-hole assemblies required to drill a directional well.

Even greater improvements in directional drilling effectiveness are possible, however, from some of the lesser known yet highly successful applications of the steerable concept which have been used, on a limited basis, in various oilfields around the world and which have the capacity for more general use.

This paper describes the implementation and results of a number of these less common applications. The examples serve to illustrate the way in which the steerable system concept supported by comprehensive drilling software can alter the design and planning of directional wells. Many design goals may now be achieved which were previously considered to be too costly or technically difficult. by conventional drilling methods and the future of drilling will involve a high degree of planned flexibility allowing for real-time changes throughout the drilling process.
Remote and Difficult Onshore Drilling Logistics
Authors: Dodds R. G. , Twa W. L.
Published: December 2007

The onshore search for large, or giant oilfield discoveries is leading operators into remote and sometimes environmentally difficult areas of the world. This paper will explore the role of the drilling contractor in the evaluation, design and execution of logistical programs that overcome, on a cost efficient basis, the distance and obstacles that may be encountered in the movement of the drilling package to remote and difficult exploratory drilling site(s). It will be based largely upon first hand operational experience in the continent of Africa, and it will describe the steps that were taken to satisfy operator objectives.

The importance of a well-designed remote and difficult logistics program is easily understood when one considers the fact that the costs for logistical support often exceed the cost of the exploratory well(s). Furthermore, in today's competitive market, the drilling contractor often assumes more of a risk on the logistics portion of a drilling program through a modified turnkey contract. Thus the unique and successful drilling projects that will be used as examples will be of benefit to operator and contract personnel attending the SPE/IADC 1989 Drilling Conference.
New MMS Drilling Regulations
Authors: Martin W. H.
Published: December 2007

The consolidation of the rules governing oil, gas, and sulphur operations on the OCS, which was proposed in the Federal Register on March 18, 1986, was published as a final rule on April 1, 1988, and became effective 60 days later on May 31, 1988.

The Minerals Management Service (MMS) would have liked to have published the final rule sooner but the time required to develop the final rule was time well spent.

The comment period on the rule was originally set at 90 days and was to have closed on June 16, 1986. At the request of many of the commenters, the comment period was extended an additional 90 days until September 15, 1986.
The Economic and Operational Effects of the 1988 Promulgated Federal Regulations on Offshore Drilling Operations
Authors: Graff R. L.
Published: December 2007

Compliance with governmental regulations is a major concern for all offshore operators and contractors who drill in Outer Continental Shelf (OCS) waters.

Drilling operations in these waters come under the jurisdiction of the Mineral Management Service (MMS). Failure to comply with these regulations can result in being issued a written notice called an incident of non-compliance (INC), rig opera-tions shut down, or depending on the severity of the infraction, fines and imprisonment.

This paper will review MMS Order 250- -Subpart D (Drilling Operations), which replaced OCS Order 2 in 1988. The intent is not to debate the merits of the new Orders, but to examine their present and future impact on operating practices, from both safety and economic perspectives.
Selecting and Installing Top Drive Drilling Systems on Mobile Offshore Rigs
Authors: Hock C. J.
Published: December 2007

When top drives are installed on offshore drilling rigs, a number of equipment and modification choices are available to the drilling contractor. In this paper each major component of the top drive support equipment is examined along with the rig modification necessary for a workable top drive installation.

Reasons for extending the derrick are presented along with alternative traveling assemblies. The guide rail and dolly system are discussed along with changes to the existing rig floor drilling equipment. The driller's controls, top drive power, cooling, and special systems are addressed, standards, classification society and regulatory agency considerations are discussed where they have presented problems to top drive installations. Finally, guidance is given about the scheduling of a top drive installation.
Controlled Horizontal Drilling
Authors: Conti P. F.
Published: December 2007

Very recently a conventional drilling assembly, directional Measurement While Drilling (MWD) and steerable system were used to drill the first successful horizontal well in Michigan's shallow Antrim gas zone. This essay is an analysis and evaluation of the technology applied and the procedure used to achieve a successful horizontal status. An explanation of the controlled drilling methods used to maintain a lateral status in the "Hot Zone" (anticipated high gas producing zone) is provided as well as case history information from the actual field operations.

An analysis of the economics of such a project is examined, along with a comparison of this well design versus straight hole drilling. The key issue in this project is the evaluation of the gas production, which is the prime economic factor that will determine the future of similar projects. The hypotheses offered by various operators were researched, and comparisons made to proven theories provide actual case history data for future lateral wells As more well information becomes available from current projects, it is anticipated that operators will plan new projects to maximize their production using their research and case history data to minimize their expenses.

The results of this lateral project are objectively presented so that specific conclusions may be drawn. Similar projects are highlighted to ensure that a fair and accurate evaluation can be derived from this project.
Horizontal Drilling in Mature Oil Fields
Authors: Rehm W. A. , Garcia A.
Published: December 2007

Twenty-five wells in mature fields have been recompleted with a newly drilled horizontal leg. The experience has established a series of proven techniques for reopening, drilling, and recompletion. Additional oil recovery demonstrates economic viability of the system.
Laboratory Hot Waterfloods Prior to and Following Steamfloods
Authors: Shen C-W.
Published: December 2007

Three-dimensional, high-pressure, physical models were used to determine the combined effects of hot waterflooding and steamflooding. The first case involved a hot waterflood prior to a steamflood; the second case was a study of a hot waterflood following a steamflood.

In this homogeneous sandpack model representing a one-quarter of 2-1/2 acre (1.0 ha), 88-ft (26.8 m) thick, confined five-spot pattern, the following were observed:

A steamflood following a hot waterflood recovered more oil than a steamflood alone. This increased recovery is explained by a change in the heat flow pattern in the formation. Instead of ascending to the upper region of the formation, the steam, following the established hot water channels, moved along the lower region of the formation and contacted additional oil. This improved the vertical conformance of steam injection. A hot waterflood following a steamflood produced little additional oil. The hot waterflood moved the oil that was bypassed by the steamflood, but a good portion was pushed into the depleted steamflooded zone and was not produced.
Gas/Oil Relative Permeability Calibration With Observed Time Drainage Performance
Authors: Shook R. A.
Published: December 2007

An empirical technique to calibrate gas-oil relative permeability data to observed time drainage performance from repeat Compensated Neutron Log (CNL) data analysis has been developed. The technique will yield a unique estimate of endpoint residual oil saturations by observing the rate of time drainage after gas has moved through a logged interval. The technique will also establish the correct relationship between the kv/kh ratio and the exponent in the oil relative permeability expression (the Corey exponent) by noting the absolute oil saturation value existing at the onset of time drainage, as measured in a CNL logging program. By estimating the kv/kh ratio of a horizon by core work, statistical log interpretations, vertical pulse test, etc., the corresponding required oil exponent is determined. Thus, the endpoint residual oil saturation as well as the shape of the relative permeability curve can be calibrated based on the observed time drainage performance.

Some important observations made in the study are:

After the gas front has moved through an interval, the rate of oil drainage is independent of voidage rate and PV gas throughput. This is also true for a bypassed oil lens on top of a shale. The rate of drainage is insensitive to vertical locale, kv/kh ratio, and the relative permeability exponent. These parameters affect the absolute oil saturation values over time, but do not significantly impact the. rate of oil saturation change behind the gas front. After gas front passage, the rate of oil saturation change behind a gas front is most affected by the residual oil saturation to gas. A relationship between the kv/kh ratio and the oil relative permeability exponent exists that will correctly yield the oil saturation found at the onset of time drainage.
Drilling Aspects of the Deepest Well in California
Authors: Shultz S. M. , Schultz K. L. , Pageman R. C.
Published: December 2007

On May 30, 1985, an Exploratory Well 934-29R was spudded in the Elk Hills Naval Petroleum Reserve #1 at Tupman, California. Bechtel Petroleum Operations, Inc. and the Department of Energy cooperated in a joint effort to drill a 25,000 foot well and determine whether or not hydrocarbons are present at the deeper depths. Several zones of interest had been drilled through when the well reached a final T.D. of 24,426 feet (Figure #1). This paper will reveal some of the more significant drilling technology used and also problems encountered while drilling the deepest well in California. Points to be covered will include the following:

Casing Design to Accommodate 5″ Drill Pipe LVT Oil Base Mud Diamond Bit Design Utilization of Turbodrills Cementing
Record-Setting Top-Drive Installation
Authors: de Haas R.
Published: December 2007

Topdrives are found on rigs all over the world. Generally the procedure is, considering the amount of work to be done, to take the rig into a shipyard and do the job there and depending on which modifications are required, this takes between two and four weeks.

When a topdrive had to be installed on the "Neddrill 3", a cantilevered jack-up of the CJ46 design with a 147' U.I.E. derrick, the required time was not available. It was decided to install the topdrive and continue to be operational; a major task for management, engineers and rigcrew.
Wet Gas Flow Measurement
Authors: Nederveen N. , Washington G. V. , Batstra F. H.
Published: December 2007

Venturi meters, used in combination with relationships published for orifice plates to correct for wetness, can accurately meter wet gas. This allows separators to be omitted from gas field developments where they were used only to remove entrained liquid before the gas was metered. Vortex meters have also been investigated but they do not give predictable readings. A calibration technique based on the tracer dilution technique using inert gases has been developed to calibrate wet-gas meters.
Potential Geomechanics Problems Resulting From Closely Spaced Storage Wells in Dome Salt
Authors: Ratigan J. L. , DeVries K. L.
Published: December 2007

Limited area often requires closely spaced solution mined hydrocarbron storage wells. The technical basis for spacing regulations is often unclear. The analysis presented in this paper suggests that web thicknesses between adjacent wells can be significantly less than required by state rules or Strategic Petroleum Reserve design guidelines.
The Analysis of Gas Well Test Data Distorted by Wellbore Storage Using an Explicit Deconvolution Method
Authors: Blasingame T. A. , Johnston J. L. , Lee W. J. , Raghavan R.
Published: December 2007

This paper presents a new method for analyzing gas well test data distorted by wellbore storage. The method that we propose in this paper is an explicit deconvolution method which is independent of the reservoir model. As is well known, the deconvolution procedure corrects test data influenced by wellbore storage and yields the pressure profile that would have existed had the afterflow rate been zero. Deconvolved data may then be analyzed using conventional semilog and type curve techniques.

This new deconvolution method has an explicit solution; i.e., a single formula corrects for the wellbore storage effect using measured bottomhole pressure and sandface flowrate. Previously introduced methods are tedious and difficult to apply. This method is much faster, gives equitable accuracy, and is easy to use. In the event the sandface flowrate is not measured, methods to estimate the sandface rate using our proposed wellbore material balance equation are presented.

The method given here is simple enough to be used in hand calculations; algorithms to apply this method are outlined in this paper.
A New Stimulation Technique for Acid-Sensitive Formations
Authors: Peters F. W. , Cooper R. E.
Published: December 2007

A new technique has been developed to stimulate heavily damaged, high-permeability wells that cannot be successfully acidized. Many sandstone producing formations in the ASIA-PACIFIC region fall into this category, for a variety of reasons.

The technique restores productivity in damaged wells by providing a very short, highly conductive fracture through the damaged area around the well bore. Given adequate fracture conductivity, combined with enough length to ensure the fracture penetrates virgin formation permeability, production can be restored to levels greater than a well's natural capacity to produce in its undamaged state.

This paper includes a discussion of some of the well conditions that can indicate a good candidate for the new application, as well as guidelines for designing the treatments. The technique is not easily modeled with conventional fracture simulators, but simple volumetric determinations have been used successfully to select effective treatment sizes. Two case histories are documented, plus the design considerations for two additional cases. The examples include applications for a variety of well conditions.
Performance Testing of Jar Accelerators
Authors: Kyllingstad A. , Slørdal L. H.
Published: December 2007

This paper presents results from a test program on jars and jar accelerators. Ten different accelerators in the range of 6.25" OD to 8" OD have been tested in a horizontal jarring rig built especially for this investigation. The test program comprises both single tool tests and full jarring tests where accelerator's are tested together with jars. Slow loading and deloading of the accelerators has revealed great differences in performance. In general hysteresis loss is higher than expected and efficiency is lower than expected from suppliers claims. Temperature tests with heated tools have shown that the temperature has a large effect, especially for accelerators using a compressible fluid as spring elements. Finally, measurements during full jarring tests where the accelerators are deloaded very fast, clearly show that dynamic friction losses are quite significant for some of the tools. The test results and their applications to real field jarring are discussed.
The Seismic Method A Useful Tool In Underground Gas Storage Exploration
Authors: Engquist Bruce E. , Reinerio E.D.
Published: December 2007

1967 REGION X MEETING SOCIETY OF PETROLEUM ENGINEERS AMERICAN INSTITUTE OF MINING and METALLURGICAL ENGINEERS SEPTEMBER 9, 1967 EVANSVILLE, INDIANA

The exploration for subsurface structures in northern Illinois suitable for the storage of natural gas is often handicapped by a lack of geologic data. Seismics is a geophysical tool that can serve u an aid to an exploratory drilling program. The purpose of this paper is twofold: first, it will briefly explain the fundamentals of seismics; and second, it will outline the details of an actual exploratory seismic survey. The geological interpretation was inadequate due to a limited density and distribution of data. The geophysical interpretation was also inadequate until correct velocity was applied to the measured time to obtain depth. Cooperation of the geologist and the geophysicist is essential to insure the correct integration of all data. In this manner, the final geologic evaluation of an area will have encompassed all available data in the search for subsurface structures.

Introduction

The area of exploration of the Northern Illinois Gas Company for gas storage structures is essentially limited to the northern one-third of the state. This is north of the Illinois Basin and geologic data from petroleum exploration is extremely sparse. All operating storage fields of Northern Illinois Gas Company are aquifers, barren of hydrocarbons, with a natural water drive.
Drilling Kick Statistics
Authors: Wylie W. W. , Visram A. S.
Published: December 2007

A drilling occurrence is a non-routine event that may be encountered while drilling a well such as a water flow, lost circulation, a kick or a blowout. In Alberta information on occurrences are reported on the drilling tour reports which are submitted to the Energy Resources Conservation Board (ERCB), the Government regulatory body. Drilling information is extracted and stored on an integrated database. The drilling ocurrences and specifically the kicks and blowouts, for a ten year period (1979-1988) have been analyzed to determine trends and frequency rates. The kick information extracted included the well identifier, the operation in progress, the occurrence date, the occurrence depth, the well's total depth, the finished drilling date, and the type of well (development or exploratory).

The analysis indicated that the risk of a kick is significantly greater for exploratory wells than for development wells, and also increases significantly for deeper wells. The analysis of the operation in progress at the time of the kick indicates similar rates for both development and exploratory wells, and that failure to keep the hole full is the major cause of kicks with drilling with inadequate density fluid a close second.
Technique to Assess Directly Make-Up Contact Stress Inside Tubular Connections
Authors: Slack M. W. , Salkin H. , Langer F. H.
Published: December 2007

In premium oilfield tubular connections, control of make-up prestress or contact pressure on the seal is critical to structural and leakage integrity. Current technology relies on indirect methods, such as torque-turns and short term internal gas pressure tests, for evaluation of this contact pressure.

This paper describes a new technology that directly measures contact pressure between mating solid parts. This technology uses an ultrasonic reflection amplitude pressure (URAP) correlation, and is based on the reflection characteristics of elastic waves from thin films, such that the thread compound 'squeeze film' functions as a quick, safe and non-intrusive stress gauge.

A brief treatment of the physics used to explain the measurement is given with empirical correlations of the URAP measurement to contact pressure. Development and testing of a prototype rig floor tool with results from laboratory and field trials are presented to demonstrate the feasibility of applying this technology to measure the actual connection prestress in real time. This data clearly demonstrates the potential for URAP to become a reliable technique for quality control and quality assurance in the make-up of premium connections.
Wellbore Stability Analysis: A Review of Current Methods of Analysis and Their Field Application
Authors: McLean M. R. , Addis M. A.
Published: December 2007

Hole problems during the drilling phase of operations are often the consequence of mechanical wellbore instability. This leads to higher than necessary drilling costs. A number of analytical and numerical models are available for the diagnosis and prediction of wellbore instability; this paper reviews the merits and pitfalls of applying these models to field situations. Attention is focused on the peak-strength criterion and constitutive behaviour model. Anomalies from the incorporation of the intermediate principal stress into peak-strength criteria are highlighted. To illustrate the reliability of a number of models, their predictions are compared with laboratory results, and with a case history of a horizontal well drilled in the Cyrus Field in the North Sea.
The Application of "Mechanical" Borehole Stability Theory to Development Well Planning
Authors: Fleming N. H. , Ronaldi R. , Bruce S. , Haryanto J.
Published: December 2007

Shales are widely blamed for drilling problems. Such problems are frequently attributed to mud/shale chemical interaction, abnormal pore fluid pressures and excessive overburden or tectonic earth stresses. Problems experienced include 'lost time' due to tight hole, sloughing, and even loss of the hole. This paper attempts to evaluate the practical application of mechanical stability studies to directional well planning and emphasizes the importance of a 'combined approach' when tackling specific shales, where problem severity is frequently best understood in terms of both borehole stress and chemistry.

An analytical technique has been developed, which utilizes wireline sonic, bulk density and gamma ray data from offset wells, to estimate the mechanical integrity of the wellbore with depth and hence the mud weights required to support the borehole wall without fracturing weaker beds. Increasing hole inclination usually narrows the choice of safe operating mud weights. The log was evaluated in CONOCO's Ikan Pari development field in Block 'B', South China Sea Indonesia, where shale 'bridging' and 'sloughing' had plagued earlier drilling campaigns. These recent efforts to identify the causes of hole problems in Block 'B' demonstrate the cost saving potential of stability studies to development well planning and should be applicable to many other areas. A stability log from the vertical well in an offshore development field can be re-run at the planned well trajectories; this can provide valuable input to casing seat and mud weight selection, cement program design, fracture gradient calculation, drilling procedures through problem sections and directional well planning, (particularly high angle profiles).
Design and Development of High-Strength, Sour Service Drillpipe
Authors: Shivers R. M. , Greer J. B. , Smith J. E.
Published: December 2007

Drillpipe for deep, sour, highly deviated, abnormally pressured Norphlet wells in the Mobile Bay Area requires tensile and torsional strength in excess of conventional API Grade X-95 drillpipe with NC50 tool joints. It was decided to construct a drillstring from 105,000 psi [724 MPa] minimum yield strength steels with optimum chemical composition for welding, toughness, and resistance to H2S exposure. Design load requirements led to the selection of a tool joint with a secondary torque shoulder. Quality assurance testing indicated that an SSC resistant, Grade CG-105 grade drillpipe is feasible to manufacture.
Studies of Fractures Induced During Cyclic Steam Injection
Authors: Reis J. C.
Published: December 2007

Induced fracturing during cyclic steam injection was studied in two heavy oil reservoirs in California. In a shallow, unconsolidated sandy-conglomerate, steam induced fracturing was chaotic, with multiple events occurring over a period of days. Predominantly horizontal fractures appeared to open and close in various locations and at various times. Not all of the temperature events observed in observation wells that suggested fractures correlated with changes in the injectichon pressure. No model for steam flow in this reservoir could be developed. In a deeper, less permeable, more consolidated formation, two vertical fractures simultaneously opened along the wellbore at different depths at the start of injection and remained open during injection and production. The fractures were co-planar and were separated by a shaly interval. Multiple fracturing events were not observed. A simple thermal conduction model was developed that successfully matched the measured data and allowed the effective reservoir permeability to be estimated.
Detailed Mapping of Fluvial Sand Bodies Improves Perforating Strategy at Kern River Field
Authors: Brelih D. A. , Kodl E. J.
Published: December 2007

Detailed geologic mapping can greatly enhance perforating and production strategies in a complex field under active steamflood. Some of the smaller, thinner sand bodies, overlooked because of discontinuity, may actually produce significant amounts of oil if their development is wisely planned. This involves identification of the wells in the downdip locations and/or in the thickest parts of the structure and perforating when preheat from an adjacent steamflood is realized.
Variations in Thermal Properties with Lithology in the San Joaquin Valley, California
Authors: Reis J. C.
Published: December 2007

Geothermal gradients and thermal conductivities were measured in three oil-saturated formations having different lithologies at one location in the southern San Joaquin Valley, California. The three lithologies in order of increasing depth were a sandy conglomerate, diatomite, and porcelanite, respectively.

The geothermal gradients were measured with arrays of thermocouples in dry observation wells prior to steam injection in the area. The measured gradients for the three lithologies were 1.8, 5.8, and 2.3 °F/100 ft (33, 106, and 42 mK/m), respectively. The geothermal gradient through the sandy conglomerate and the porcelanite are consistent with published valued for this area (Sass, J.H., Galanis, S.P., Jr., and Munroe, R.J.: Measurement of Heat Flow by a Downhole Probe Technique in the San Joaquin Valley, California (1982) USGS Open-File Report 82-819), but the gradient through the diatomite is significantly higher.

Thermal conductivities of these formations were measured on core taken from nearby wells. Because thermal conductivity varies with porosity and oil saturation, core samples were selected for each lithology that had values equal to the average of their respective formations. The thermal conductivities were measured using the steady-state, divided-bar method at 150 and 300 °F (66 and 149 °C). The measured values for the sandy conglomerate at the low and high temperatures values were 0.71 and 0.77 btu/(hr-ft2 -°F/ft) (1.22 and 1.33 W/m-K), respectively. The values for the diatomite were 0.35 and 0.51 Btu/(hr-ft2-°F/ft) (0.61 and 0.88 W/m-K), respectively, while the values for the porcelanite were 0.63 and 0.67 Btu/(hr-ft2-°F/ft) (1.09 and 1.16 W/m-K), respectively. The thermal conductivity of the diatomite was considerably lower and its temperature dependence was greater than that of the other formations. These data are consistent with published values for other sedimentary rocks (Anand, J., Somerton, W.H., and Gomaa, E.: Predicting Thermal Conductivities of Formation from Other Known Properties, Soc. Pet. Engr. J. (1973) Vol. 13, No. 5, pp. 267-273).
Formation Damage Prevention and Adsorption Studies of Nonionic Surfactants in Sandstone Reservoirs
Authors: Paktinat J. , Dunlap D. D.
Published: December 2007

The adsorption of chemical additives used in conjunction with matrix acid systems presents an obstacle to improved stimulation performance. The primary purpose of surfactants used in acid treatments is to reduce acid surface tension and contact angle and prevent acid/formation fluid emulsion. However, many of these chemicals adsorb rapidly in sandstone media, reducing their effectiveness in the formation.

This study describes the laboratory and field investigation of various surfactant components and their adsorption properties in sandstone. A six foot long sandstone core apparatus provides the primary means for laboratory investigation, Various surfactant constituents such as ethoxylated nonyl phenols and linear alcohols are investigated for their adsorption properties. This data may be used to develop chemical additive systems which optimize chemical penetration in a sandstone formation.

The primary results of this study include:

Improvement in penetration of surfactants when linear ethoxylated alcohol is used rather than commonly used nonyl phenol ethoxylates. The C12-C13 alcohol with ethylene oxide ratios of 9 to 15 moles shows to be the most effective for formation damage prevention.