bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Engineering and Technical Aspects of Polymer Flooding in Daqing Oil Field
Authors: Wang Demin , Li Qun , Gong Xiaohong , Wang Yan 
Published: December 2007

Abstract
Petroleum is a non-renewable resource, it is crucial to a country’s economic development. However, during the development of reservoirs, especially at a high water cut stage, its economic and technical indexes will all turn worse. The water cut will increase, production rate decrease, capital construction and production costs increase. How to produce the 60~70% oil remaining underground is a task that reservoir engineers all over the world are striving to solve.
In the 60~70’s, petroleum professionals in many countries conducted extensive studies on polymer flooding technology. Screening and evaluation methods were set up; field tests were started. But from statistical data, the incremental recovery of polymer over water flooding was on the average only 2~5% OOIP (original oil in place), the economic results were not satisfactory. This directly influenced the industrial application of polymer flooding.
Since Daqing Oil Field is not suitable to use thermal and miscible methods to enhance oil recovery, one of the main targets was to have breakthroughs in polymer flooding technology. After a long period of research, a more thorough knowledge of the entire polymer technology was obtained. A breakthrough was obtained on the common belief that polymer flooding cannot increase the micro-scale displacement efficiency, the visco-elastic properties of polymer fluid is the crucial factor of increasing the displacement efficiency was proposed, deepening the knowledge on polymer flooding mechanism. A normalized method to more accurately evaluate the incremental recovery of polymer flooding was developed. An optimization method to determine the molecular weight and slug size of polymer drive fluid was developed. Numerical simulation methods were advanced. A highly automated, technically advanced method of "centralized preparation, localized injection" of polymer fluid and produced polymer fluid treatment and utilization technology was developed. Polymer injection well completion and multi-zone injection technology was developed.
From 1995, Daqing Oilfield started to industrialize polymer flooding. By the end of 1999, the annual production was more than 8 million tons of crude, the cumulative production more than 20 million tons with sales revenue of more than 20 billion yuan (RMB). Practice has shown that the polymer flooding can increase the recovery be more than 12% OOIP, its production cost is comparable to that of water flooding.
Mordovo-Karmalskoye Field: The Bitumen Composition in Productive Strata after Passing of the Combustion Front in Well
Authors: Kayukova G. P. , Romanova U. G. , Sharipova N. S. , Smelkov V. I. , Uspenskiy B. V. , Romanov G. V. 
Published: December 2007

Abstract
The specific features of the composition of both natural bitumens of the Mordovo-Karmalskoye field and products of the bitumen thermal transformation in strata after passing of the combustion front in a well are studied.
The composition of organic matter and its bitumen components left in reservoir after passing of the combustion front and the parameters of bitumen which underwent no artificial impact are compared. The combustion is found to cause the deep transformations in the bitumen composition and the differentiation of bitumen properties through a cross section. The rather light bitumen (density is equal to 0,94 g/cm3) is in the low concentration in the roof part of stratum. A content of paraffin-naphtene hydrocarbons, particularly n-alkanes, increases in the hydrocarbon part of bitumen. Accordingly to the group and hydrocarbon compositions, the elemental composition is altered, the hydrogen content increases and the sulphur content decreases. Contrarily, the bitumen in the combustion interval is heavier (1,013 g/cm3). A quality of the bitumen is minimal there. The interlayers having an enhanced content of the insoluble organic compounds are found. The high content of asphaltenes causes the low hydrogen content and the high carbon content in the bitumen composition. All these parameters are abnormal if to compare with the ordinary, non-transformed bitumens of the Mordovo-Karmalskoye field. In the lower part of cross section underwent no combustion, the content and composition of bitumen become ordinary for the productive thickness. At the same time, the lower oil content and the higher content of asphaltenes and sulphur in bitumens are an evidence to the displacement of light to the productive wells hydrocarbons simultaneously to passing of the combustion front. That confirms the earlier observed fact that the oil is produced at the part of reservoir which underwent no in situ combustion. In addition to the alterations in the organic matter composition and content, the bitumen-bearing rocks are also transformed, particularly a ratio between iron(II), iron(III) compounds and pyrite is changed. The revealed factors which effect the quality of recovered bitumens and the alterations in the mineralogy make possible to control the temperature regime and passing of the combustion front.
2D and 3D Multi-Domain Iteration Statics in Complex Areas
Authors: Mao Jingen , Liang Xiuwen , Zhang Nianchun 
Published: December 2007

Abstract
In view of large residual static correction values after field static correction in complex areas, the field near-surface data and field static correction data are used as the initial condition of the method. The first break time is used for the basic constrain of the method. The residual time shifts can be determined in common-shot, common-receiver and common-offset domains. Thus, the global optimized residual static correction values are estimated by doing statistics of a great deal of data and by making orthogonal iteration and step-by-step approximation. After being repeatedly revised, this result plus datum correction values forms the final static correction values. This paper takes actual data as example to show the good application results of this method.
A Comprehensive Model of Multilateral Well Deliverability
Authors: Chen W. , Zhu D. , Hill A. D. 
Published: December 2007

Abstract
We developed a deliverability model to predict the performance of multilateral wells. We first constructed a horizontal lateral model, which couples a reservoir inflow model with a wellbore flow model to calculate the production rate from each lateral. Pressure drop along the lateral was considered in the model. Then we implemented the lateral model into a well system with more than one lateral commingled to a main wellbore. The production from each lateral, the overall production rate, and the pressure in the well system are predicted by the multilateral deliverability model. For reservoir inflow, we have developed a new model using an imaging well method to calculate a single-phase inflow performance relationship (IPR) for a segmented horizontal lateral. The results from the new model are compared with existing analytical models. For flow in the laterals, we adopted single phase and two phase wellbore flow models. The single-phase lateral flow model incorporates frictional and accelerational pressure drop, and also the pressure drop caused by inflow turbulence. The two-phase lateral flow model uses the Beggs-Brill correlation or Ouyang’s homogeneous model which accounts for the effects of wall inflow, acceleration and flow patterns.The pressure drop in the tubing from the upper most lateral to the surface was calculated using a two-phase flow correlation.
We present example calculations for a well with three laterals draining separate reservoirs. The examples illustrate the effect of interference between laterals on lateral and overall well performance.
Improved Experimental Characterisation of Cement/Rubber Zonal Isolation Materials
Authors: Bosma M. G. R. , Cornelissen E. K. , Schwing A. 
Published: December 2007

Abstract
Recently, various companies published sophisticated design methodologies to engineer the ‘cement’ sheath in a oil/gas well completion such that the zonal isolation would remain intact (i.e. pressure tight) during its projected lifetime. Loading within a prescribed design envelope (e.g. pressure and/or thermal cycling or mechanical compaction processes) are the main considerations.
Improved performance of a candidate zonal isolation material is achieved by adjusting its material properties, especially the Young’s modulus and the compressibility.
These earlier studies indicated that apart from a proper mechanical characterisation of the ‘cement sheath’ (preferably described by non-linear material models), the in-situ stresses in the ‘cement’ play a prominent role as well. The latter are influenced by the volumetric behaviour of the slurry during setting and the thermal expansion coefficient of the set ‘cement’.
However, often these parameters are not known for ‘real life’ well construction materials.
Therefore, Shell International E & P B.V., the Netherlands, decided to design and construct dedicated laboratory equipment to determine those parameters for commercial ‘cement’ formulations at conditions encountered in typical well completions.
A first feature of this unique system (which can operate at pressures up to 1500 Bar and temperatures up to 300°C) is to monitor i) the progress of the ‘setting’ reaction of Oil Well Cements and or thermosetting resins, ii) their reaction behaviour (from the onset of gelling to the ‘final set’) and iii) the softening or swelling phenomena encountered in thermoplastic and thermoset materials.
The apparatus has inter alia the same functionality as conventional API Cement Consistometers or Ultrasonic Cement Analysers. However, it can also be used in combination with self-vulcanising rubbers, that cannot be used in the conventional API devices.
A second aspect of the apparatus is the determination of the volume changes (at constant pressure) or alternatively the pressure changes (at constant volume), during setting of the cement (or resin) system.
All measurements can be performed at either isothermal conditions or for prescribed temperature sweeps over time. Either volumetric properties (shrinkage or expansion) or compressibilities of cements / resin systems can be measured in a time frame ranging from the onset of gelling to far beyond ‘final set’.
In yet another operational mode, the volume change of set materials as a function of temperature (i.e. their volumetric thermal expansion coefficient) can be quantified.
In addition to a review of the principles of this novel apparatus, this paper also presents a typical application of the data in a Plug and Abandonment design (i.e. the Finite Element Engineering design of a thermally pre-stressed ‘rubber’ abandonment plug).
CNOOC and Industry Working Together – Huizhou 26-1 North Development Project
Authors: Sheng Lin Yao , Pratico Antonio , Hassing James R. 
Published: December 2007

Abstract
The Huizhou 26–1 North development project began with the discovery in September 1997 of an extension of the Huizhou 26–1 oil field, located north of the Huizhou 26–1 platform. Based on the information available after the discovery, the accumulation appeared to be justifiable for a project. However, reserves on the undrilled side of a fault were recognized as unproven. With the low oil prices that existed in late 1998 and early 1999, it was difficult to justify a decision to proceed with development. The offshore installation window and marginal economics of the project could not support an up-front expendable delineation well. Evaluation indicated that development as a subsea tieback to Huizhou 26–1 platform was potentially viable, but a wrong decision to commit to use either one or two wells would be very damaging to the economics of the project. Faced with those challenges, CNOOC, Agip, Chevron and Texaco agreed to initiate development of the accumulation without a final decision as to the number of wells. This allowed the operator, CACT Operators Group, to quickly begin the development of the accumulation and provided sufficient flexibility to customize the project as new information became available. The project was completed on June 10, 2000 with satisfactory economic results as a one-well field.
Coupled Reservoir Simulation Applied to the Management of Production Induced Stress-Sensitivity
Authors: Jin M. , Somerville J. , Smart B. G. D. 
Published: December 2007

Abstract
Reliable data input into the reservoir simulator of production-induced changes in matrix and fault permeabilities is essential for the successful planning and management of oil and gas reservoirs. Withdrawing and injecting fluid from/to the reservoir causes a change in pore pressure, which in turn, changes the three dimensional effective stress state. The stress path followed by the reservoir controls the evolution of the effective stress state, and with it the changes in deviatoric stresses which cause reservoir rock deformation and permeability changes. In order to allow for these effects, a new type of reservoir simulator – the stress-sensitive simulator – is required. This paper presents the results of a stress-sensitive simulation using a nonlinear finite element geomechanics model coupled to a finite difference fluid flow simulator, applied to a typical North Sea reservoir. This reveals the effects of dynamic changes in permeability and the reactivation of faults on the reservoir performance.
In the 3D coupled field-sized reservoir model, the permeability of intact rock is stress sensitive; faults are represented by joint elements with a permeability which is strain sensitive. The stress path is recorded and the hysteresis effect is considered in an interface program to modify the permeability according to the current and previous stress states. The results show that the evolution of the stress state, captured as a stress path, significantly affects the oil production profile. The pressure recovery caused by injection may also be diminished by hysteresis. The results also show the spatial and temporal changes in stress state, which are useful data for the analysis and exploitation of production induced anisotropy in permeability, with particular reference to the location of by-passed oil.
Geology And Seismology: An Effective Combination In The Evaluation Of Underground Natural Gas Storage Prospects And Fields
Authors: Miller Robert R. , Reinerio Eugene D. 
Published: December 2007

Abstract
The primary purpose of this paper is to show the benefits obtained from coordinating seismic and geologic information into an acceptable interpretation of the subsurface geologic conditions existing at a particular gas storage project.
During 1974 and 1975, seismic explorations, utilizing the common depth point (CDP) technique and the Vibroseis energy method, were conducted at Northern Natural Gas Company's Dallas Center Aquifer Storage Prospect in central Iowa and Lyons Depleted Gas Field Storage Prospect in central Kansas. Although these two areas are geographically far removed from one another, the CDP technique is quite applicable to each of these geologic provinces.
The petroleum engineer's need for detailed information about the configuration and integrity of the gas storage reservoir often surpasses the geologist's knowledge, based on a finite number of drill holes. The seismologist, working in close association with the geologist and utilizing modern field recording techniques, instruments and computer data enhancement, can add a new dimension to the understanding and thinking of both the petroleum engineer and geologist.

Introduction
The Dallas Center Anticline, located in Dallas County, Iowa, is 300 miles northeast of the Lyons Anticline, located in Rice County, Kansas. Both of these geologic structures have been evaluated by shallow and deep drill holes and by common depth point seismic work. The purpose of this evaluation was to prove their purpose of this evaluation was to prove their relative worth either as an aquifer gas storage prospect (Dallas Center) or to more accurately prospect (Dallas Center) or to more accurately define the boundary faults associated with an abandoned gas field (Lyons). Figure 1, an index map, shows the location of these two anticlines in relation to each other and to State and County boundaries, as well as major geologic features.
Geologically, the two anticlines are in entirely different provinces. The Dallas Center Anticline is located at the extreme northern end of the Forest City Basin, eight miles east of the southeastern edge of the Mid-continent Gravity-Magnetic High. The Lyons Anticline is located on the southern half of the Genesco Uplift, the eastern most lobe of the larger Central Kansas Uplift.
The Dallas Center Anticline was originally delineated by Northern Natural Gas Company from preliminary structural mapping of shallow farm preliminary structural mapping of shallow farm water well data.
Impact of Clay Acidity on the pH of Invading Fluids
Authors: Gdanski Rick 
Published: December 2007

Abstract
It is commonly understood that clays have surface hydroxyls that are available for various interactions. However, this paper demonstrates the magnitude of the interactions possible by the natural acidity that clays possess. Laboratory experiments with a 3-ft Hassler sleeve and unconsolidated sand/clay-packed columns demonstrated that the pH profile of buffered and unbuffered high-pH fluids can be readily understood in terms of the natural acidity of clays. The impact of the clay acidity on brine pH was much larger than imagined. In fact, the original goal of the work was to investigate the attack of hydroxide on clays. However, it was found that the dominant mechanism for lowering the injected fluid pH was clay acidity. The impact oftotal clay acidity (TCA) on injected-fluid pH proflies was numerically demonstrated with the new model for both linear and radial flow. These two geometries are relevant to leakoff during frac-packs (linear) and for drill-in fluids and matrix treatments (radial).
The Effect of Fluid Leakoff on Gel Placement and Gel Stability in Fractures
Authors: Ganguly S. , Willhite G. P. , Green D. W. , McCool C. S. 
Published: December 2007

Abstract
Chromium acetate-hydrolyzed polyacrylamide gel systems are applied in fractured reservoirs for conformance control. A portion of the gelant leaks off into the adjoining matrix during placement of the gelant in the fracture. This paper describes an experimental study on the effect of fluid leakoff on the performance of a gel treatment. The stability of a gel that is placed in a fracture and is subjected to a pressure gradient was also investigated.
Physical models of a fracture were developed to conduct displacement experiments. The models were fractured Berea sandstones that were designed to permit leakoff of the gelant into the matrix on the sides of the fracture. A polyacrylamide-chromium acetate gelant was injected into the fracture under conditions in which there was leakoff and no leakoff into the matrix. A gel did not form and the gelant was easily displaced from the fracture by subsequent brine injection when the gelant was placed without leakoff. When the gelant was placed with leakoff, a gel formed in the fracture after placement and provided significant flow resistance. Lack of gelation in the absence of leakoff was caused by diffusion of chromium from the fracture to the matrix, reducing the chromium concentration in the gelant to levels where gelation would not occur.
It was discovered that gels that were formed in a fracture ruptured when a constant brine pressure was applied at the inlet. The pressure where rupture occurred was determined for gels placed in tubing of various lengths and diameters. The rupture pressure was proportional to a ratio of the length-to-diameter.
Treatment of Super-K Zones Using Gelling Polymers
Authors: Alqam M. H. , Nasr-El-Din H. A. , Lynn J. D. 
Published: December 2007

Abstract
An experimental investigation was undertaken to modify the permeability profile of high permeability fluid zones (producing and injection) using gelling (cross linking) polymers. The first phase of this study included characterization of "super-K" zones. Computerized Tomography (CT), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and an Apparatus for Pore Examination (APEX) system were used to determine the mineralogy and pore geometry of carbonate core plugs obtained from the matrix and super-K zones.
In the second phase of the study, various gelling solutions were injected into reservoir core samples to evaluate the ability of the gel to resist extrusion and determine the robustness of the treatment chemical under downhole conditions. Core plugs used in this study were obtained from an oil producer in a carbonate reservoir in Saudi Arabia.
The results of the first phase indicated that the super-K streaks have a tortuous path. There are significant differences between the lithology and pore size distribution of the super-K zones and the normal matrix. In addition, there is convincing evidence that the super-K intervals may be fractured as well diagenetically induced.
The use of thin section petrology has highlighted potential problems in using the gel in formations that are vugular or have large diameter natural fractures. The data has demonstrated that the gel will not fully fill pore voids greater than 400 microns, and would not invade pores smaller than 70 microns.
Coreflood tests indicated that the gelling solution could be injected into either the matrix super-K or the fractured super-K. Reservoir condition aging improved the stability of the gels that were placed in matrix cores, but gave in less promising results in fractured intervals.
Physicochemical Characterization of Crudes and Solid Deposits as a Guideline to Optimize Oil Production
Authors: Carbognani L. , Contreras E. , Guimerans R. , León O. , Flores E. , Moya S. 
Published: December 2007

Abstract
A comprehensive analysis scheme devised in order to cope with solid precipitation during oil production is being currently followed in many Venezuelan production units. Three goals from the scheme are: 1. Identification of remedial actions based on deposits characterization, 2. Selection of the most efficient dispersant additive, 3. Choice of the proper solvent mixtures for cleaning production strings, when organic types were assessed to be the main components of the deposit.
This paper addresses these aspects with examples taken from a field located in eastern Venezuela.