Ali

The SPE technical journals, including SPEPO, are “peer-reviewed” technical publications. The publication of a paper in this journal indicates that the author’s peers believe that the paper represents a significant technical contribution and is founded on sound science and technology. As such, the publication of a peer-approved paper conveys a higher standard than a paper that is published in a trade journal and merely edited for grammar and legibility of figures. More important, the process of peer review helps assure the reader that the science is reliable and can be used to further the technology.

The distinction between a conference presentation and journal paper is also noteworthy. Some papers make interesting conference presentation but may not be suitable for further publication in a journal. For example, papers that just inform the industry of a new product and keep the technical details confidential are poor candidates for journal publication. Likewise, papers discussing the success of a company-specific tool or its successful field application also may fall into this category. Similarly, papers discussing unfinished and inconclusive work cannot be considered for publication.

It is not my intent to discourage anyone from submitting paper for peer review; however, knowing the minimum requirements for peer review may save time both for the authors and for the SPEPO technical editors.

Leading off this expanded issue of peer-reviewed papers is a scale-management paper. Coreflood Studies Examine New Technologies That Minimize Intervention Throughout Well Life Cycle discusses the technical problems associated with treating subsea wells and examines new technologies for scale-inhibitor squeeze treatment for both low water-cut and high water-cut subsea wells throughout their life cycle.

Oil and/or gas production can be increased in waterflooded reservoirs by stopping further water injection and depressurizing the reservoir to release solution gas. The paper Impact on Scale Management of the Engineered Depressurization of Waterflooded Reservoirs: Risk Assessment Principles and Case Study discusses the assessment and prediction of scale-related formation-damage problems that are likely to occur during the depressurization of a case-study waterflooded reservoir by use of reservoir-simulation tools.

The next paper, Measurement and Prediction of Salt Solubility in the Presence of Hydrate Organic Inhibitors, presents a novel numerical approach capable of predicting salt formation in the brine solution with or without hydrate organic inhibitors.

The BP-operated Miller field has the harshest oilfield-scaling regime in the North Sea. On average, three to four squeeze treatments per week are performed across the online wells. As such, the Miller field offers a unique opportunity to evaluate new technologies and engineering solutions in an attempt to increase the wells’ overall efficiency.  Deep Downhole Chemical Injection on BP-Operated Miller: Experience and Learning details the design criteria of the deep downhole chemical injection (DDHCI) completion, as well as the philosophy of installing such a device. It also provides details on the management strategy of using DDHCI in a proactive manner to maximize the time between squeeze treatments.

The next paper, Acid-Sensitive Aluminosilicates: Dissolution Kinetics and Fluid Selection for Matrix-Stimulation Treatments, presents a combination of laboratory testing (i.e., dissolution kinetics) and geochemical simulations that can be used to elucidate the underlying reaction mechanisms for analcime, chlorite, and illite in hydrochloric acid, and mixtures of hydrochloric and hydrofluoric acids, and to determine their impact on reservoir treatments. Guidelines for the design of matrix-stimulation treatments for acid-sensitive formations are also presented.

Considerations of Damaged Zone in a Tight Gas Reservoir Model With a Hydraulically Fractured Well discusses a method to integrate the hydraulically fractured well and the fracture environment (damaged through the leakoff of the fracturing fluid) into a reservoir-simulation model. This approach is illustrated through the analysis of a cleanup process in a damaged fractured well within a Rotliegende tight gas formation in north Germany.

Commonly used proppants include various sands, resin-coated sands, intermediate-strength ceramics, and sintered bauxite—each employed for their ability to effectively withstand the respective reservoir closure-stress environment. As the relative strength of various materials increases, so do their respective particle densities. Unfortunately, increasing the particle density leads to difficulty in placing particles evenly throughout the created fracture geometry. Intuitively, a lesser-density proppant with sufficient strength would be easier to transport and would provide increased fracture width and, hence, enhanced fracture conductivity. High Strength, Ultralightweight Proppant Lends New Dimensions to Hydraulic Fracturing Applications presents data illustrating the performance of a new ultralightweight proppant over a broad range of conditions and a discussion of relative performance in field applications.

Optimizing Fracture Stimulation Using Treatment-Well Tiltmeters and Integrated Fracture Modeling presents the results of the multiwell pilot project that was conducted in the Copper Ridge field in Wyoming to assess future development potential. Fracture-mapping results from several wells were integrated to build a calibrated fracture model that was successfully applied in the field.

Development and First Field Application of a Gel/Cement Water Shutoff System presents laboratory data showing superior shutoff behavior at high bottomhole temperatures and high differential pressures of a fluid system comprising cement mixed with gel. In a test well, this fluid system has proved to be very cost effective for solving water-production problems in oil wells.

Certain water-soluble gels and water-soluble polymers can reduce permeability to water much more than permeability to oil. Because of operational or economic constraints, the gel treatments that are intended to plug the water zones are often placed without zonal isolation. Consequently, the injected gels penetrate both oil and water zones. It has been observed in the field that oil zones often exhibit a significant “cleanup time” after placement of gel treatments. Cleanup of Oil Zones After a Gel Treatment presents a simple mobility-ratio model that can be used to predict cleanup times for both fractured and unfractured wells after a gel treatment.

The formation of a stable and nonerodible mudcake during the course of drilling is very important to eliminate mud-induced formation damage. A Novel Laboratory Method for Assessing the Erosional Characteristics of Mudcakes presents a simple, field-applicable method for predicting the erosional potential of cakes formed by muds of different chemical composition. The prediction of erosional behavior is essential in screening and selecting appropriate mud additives for producing good-quality mudcakes on the borehole wall.

The next paper, Stabilization of Gas-Distribution Instability in Single-Point Dual Gas Lift Wells, presents a simple nonlinear model that captures the essential dynamics of gas-distribution instability despite the complex nature of two-phase flow.

Permanent downhole-pressure gauges are installed to monitor the well and reservoir conditions in real time. The downhole-pressure data have been used to detect changes in reservoir properties; monitor skin, permeability, and pressure drawdown over time; evaluate the performance of well completion, stimulation, or workover; and identify reservoir connectivity. Production and Injection Profiling Through Permanent-Downhole-Pressure-Gauge Recording During a Coiled-Tubing-Conveyed Workover Operation presents a unique application of downhole-pressure gauges for production or injection profiling.

Flow Profiling by Distributed Temperature Sensor (DTS) System―Expectation and Reality presents a thermal model for single-phase and multiphase fluid flow along a vertical, deviated, or horizontal well. The model can be applied both for temperature prediction and for flow profiling by use of a measured temperature profile.

Stress distribution in a reservoir directly affects the integrity or failure of reservoir rocks. Rock failure can be engineered to improve well injectivity or productivity. The paper An Analytical Model of Temperature and Stress Fields During Cold-Water Injection Into an Oil Reservoir presents a transient analytical model that can be used to study the temperature and stress distribution induced by a nonisothermal fluid injection (i.e., conventional waterflooding).

Optimization of Commingled Production Using Infinitely Variable Inflow Control Valves presents a sequential linear programming that can be used to periodically optimize inflow control valve settings during commingled production, primarily to maximize the oil-production rate against water- and gas-production constraints.

With the advent of horizontal drilling technology, flow in long perforated pipes has become an important issue in the petroleum industry. The paper Flow in Perforated Pipes: A Comparison of Models and Experiments presents a model of pressure losses in perforated pipes that includes the influence of inflow through the pipe walls. The model compares favorably with past and recent experimental studies.

Major oil companies often require their employees and contractors to use a job safety analysis (JSA) process. A recent survey of Gulf of Mexico offshore drilling rigs and production platforms revealed that current JSAs tend to be viewed as tedious formalities and that crews comply with them only because of requirements. A New, Improved JSA Process Gets Enthusiastic Approval From Field Personnel introduces a new style of JSA that provides significant time savings and is considerably more effective in reducing the likelihood of accidents; it provides a powerful tool for on-site management. The new JSA has received enthusiastic approval from field personnel.

With emerging demands and new market opportunities expected, the ways of transporting natural gas from offshore fields and overseas sources have generated renewed interest. Compressed Natural Gas (CNG): An Alternative to Liquid Natural Gas (LNG) presents a detailed comparative analysis based on the techniques and costs for the LNG and CNG. 

In closing, this issue of the journal contains 19 technical articles covering a range of interest related to production and operations. I hope that between them, they contain something that is of interest and value to every reader of SPEPO.

As ever, if you have any comments—positive or negative—about the content of this issue, I encourage you to send them to me at syed@chevron.com.