bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing Fracture Stimulation in Low-Permeability Oil Reservoirs in the Ordos Basin
Authors: Liu Xinghui , Chang Yanrong , Lu Hongjun , Chen Baochun , Li Jianshan , Qi Yin , Wang Chengwang 
Published: October 2012

Abstract
Huge oil reserves are located in low-permeability reservoirs in the Ordos basin in China. These reservoirs have three key characteristics: low reservoir quality (10 to 13% in porosity), low reservoir permeability (0.3 to 2.0 md), and low reservoir pressures (pressure gradients of 0.0075 to 0.009 MPa/m). Fracture stimulation is essential for commercial production in these reservoirs. To better understand fracture growth behavior and to optimize treatment designs, microseismic monitoring and fracture modeling were performed for pilot wells in key areas. In some low-permeability oil reservoirs in the basin, fracture closure stress sometimes could not be obtained from commonly used pump-in/shut-in tests because pressure decline is extremely slow. Closure stress is one of the important parameters for fracture modeling. To obtain closure stress in these reservoirs, conventional pump-in/flow-back (PIFB) tests were modified and employed. Once the closure stress in the payzone was determined, the closure stresses in adjacent and/or bounding layers were estimated from sonic log and lithology data. Fracture modeling analysis was then conducted using a calibrated fracture model, which must match both the observed net fracture pressures and the fracture dimensions from microseismic mapping. This approach led to significant improvements in fracture treatment designs in these tight-oil reservoirs. The first improvement was to maximize effective fracture lengths in fracture designs. A novel staging technique was also developed to stimulate large pay intervals using a stress diversion technique without mechanical isolation. Larger treatments using a hybrid fracturing technique were recently implemented to stimulate ultralow-permeability oil reservoirs. Production results using the new stimulation techniques were significantly better than traditional techniques in the region. This paper discusses how an integrated, engineered approach was applied to stimulate tight-oil reservoirs in the Ordos basin and demonstrates the benefits of an integrated approach to developing marginal, unconventional liquid hydrocarbon reservoirs.
Systematic Evaluation of Unconventional Resource Plays Using a New Play-Based Exploration Methodology
Authors: Neber Alexander , Cox Stephanie , Levy Tom , Schenk Oliver , Tessen Nicky , Wygrala Bjorn , Bryant Ian 
Published: October 2012

Abstract
New tools are now available to provide a rigorous and systematic play-based exploration approach to the evaluation of unconventional resources. Coupled with petroleum system modeling, this methodology offers an efficient and effective approach to identify "sweet spots" early in the life of resource plays. Petroleum system modeling can be applied to predict the type and quantity of hydrocarbon in shale formations, as well as the proportion of adsorbed gas and geomechanical properties that are important for hydraulic fracture stimulation of shale reservoirs. Maps of these properties are then converted to chance-of-success maps for hydrocarbon generation, retention, and pore volume that can be integrated with nongeological factors, such as access and drilling depth required to reach target reservoirs. These play-based maps are expressed in probability units, so simple map multiplication provides a map of the play's overall chance of success, delineating the sweet spots. A similar methodology is applicable to evaluation of coalbed methane resources.
In this paper, we illustrate this methodology using examples from shale oil and gas shale plays in North America. These include data-rich plays from the North Slope of Alaska and data-poor plays from the northeastern and southern regions of the United States, which are more representative of many Asia-Pacific basins. We show how predictions from petroleum system modeling based on sparse data provide a good match with results of subsequent development drilling and production.
Petroleum system-based assessment of resources in place, combined with an assessment of overall play risk, enables companies to make decisions on acquisition of acreage early in the life of unconventional resource plays based on the probability of them containing economically viable resources.
Evaluation of A Passive Ultrasonic Log Application for Casing Integrity Assessment: A Case Study in A South Oman Field
Authors: Aditama P. , Mirza M. , Al Saadi H. , Al Wardi A. , Aprilianto E. C. , Broughton D. , Troup D. 
Published: October 2012

Abstract
The paper presents evaluation of passive ultrasonic logging tool deployed using E-line to assess casing integrity in 3 oil producing wells in South of Oman. In addition a comparison is offered between the ultrasound logging technology and a more conventional well integrity test using a hoist and multi-set plug that has been utilized to date.
The ultrasonic log was run in a selection of oil producing wells, operated by beam pump. Those wells were confirmed as having well integrity issues from well surveillance data and were causing significant oil deferment (2.2% of total oil production). Those wells have a history of cementation challenges owning to heavy losses that occur within a water bearing zone located above the pay zone. This, combined with the presence of H2S and oxygenated water at this depth, has resulted in a number of corrosion related integrity issues across the field.
The logging program was originally planned inside tubing with surface pressures of 1,800 psi but it was decided to log inside casing (without tubing) because leak was more severe than predicted (1 m3/min of leak rate). In wells A and B, leak points at 630 m and 225 m were identified and respectively verified. However, another leaking interval in well A was also identified from conventional WIT using hoist. In well C, no pressure held on surface causing lack of differential across leak which resulted in identification failure on first attempt (inside tubing). On second attempt (inside casing), unclear ultrasound reading was attained but seven leak points still can be identified after several log passes. The tool can save significant hoist time and will become viable alternative.
In conclusion this paper illustrates examples of where the ultrasonic log has provided highly accurate leak detection, significant time saving and improvements in overall operating efficiency. The limits of the technology are also discussed with recommendations provided for the application of the service based on operational experience gained during the technical evaluation.
Overview of PCP Lifting Technology Development in Daqing Oilfield
Authors: Wanfu Zhou , Guochen Shi , Gang Cao , Mingyan Lu , Mingzhan Chen , Yu Hou , Yongxin Liu , Mingyi Zhang 
Published: October 2012

Abstract
This paper presented the development of Progressing Cavity Pump (PCP) technologies in Daqing Oilfield during the past 27 years, covering the successful experiences and lessons learned. The history of PCP lifting technology development was reviewed in the round. Several main PCP techniques were presented in detailed as well, including high efficiency and low profile PCP drivehead, hollow rotor PCP water flushing technique, PCP trouble-shooting technique, and PCP logging technique, etc.
Daqing Oilfield was the largest continental oilfield in China developed from 1960. Beam pumping units was the main artificial lift method. To date, there are more than 40,000 beam pumping wells. PCP was applied in Daqing Oilfield from 1983. In the past 27 years, the scale of PCP increased at a higher rate. Till the end of 2010, 6,000 plus PCP wells were applied in Daqing Oilfield. PCP has become the second largest artificial lift method in Daqing Oilfield.
To date, a series of PCP products have been developed covering the displacement and lift arrangement for different blocks in Daqing Oilfield. Based on the study and experiences for years, a set of completed PCP system design methodology was also created for water flooding, polymer flooding, ASP flooding and other complicated conditions. The fast improvement of PCP mainly resulted from two respects: Firstly, the quick development of PCP production techniques. The adaptability and reliability of elastomer was improved effectively and matching techniques were developed as well. Secondly, the requirement of low energy consumption and environmental protection in petroleum production policies enhanced the application of PCP technologies considerably.
This paper applied a successful case study of a novel technology developed in the mature oilfield which could be a great reference for the industry.
Methods for Measurement of Solid Particles in Hydrocarbon Flow Streams
Authors: Nabipour Amin , Evans Brian , Sarmadivaleh Mohammad , Kalli Chris 
Published: October 2012

Abstract
Sand production is one of the more critical issues causing delays and high costs to the petroleum production industry. To measure solid production in the hydrocarbon stream a number of sand monitors have been developed. Such monitors are installed in the flow line and are intended to provide information such as the onset of solid production or the amount of produced solids. Most sand monitors are based on the measurement of erosion due to impingement of sand particles or measuring ultrasonic signals generated by particle impacts on the pipe wall or piezoelectric elements.
Having described the principal behind available monitors in the industry, capabilities and limitation of each type is explained in Part 1. Part 2 is comprised of a literature review carried out on the techniques which have the potential to be utilised in new generations of solids monitors. The principles of such methods as well as their advantages and disadvantages for solids monitoring applications are mentioned.
In Part 3 subjects such as improving the data quality and data interpretation of current techniques, integration of available techniques into a single piece of equipment, and ranking of the most promising cases which are worthy of further investigation are discussed.
Integrated Approach to Unconventional Reservoir Characterization: Key for Understanding Hydrocarbon Production Challenges in Kerogen and Tight-Fractured Deep Carbonate Complex in Kuwait.
Authors: Acharya Mihira N. , Kabir Mir R. , Al-Ajmi Saad H. , Al-Maia Noura A. , Kumar Ashok , Pradhan San P. , Al-anzi Ealian H. 
Published: October 2012

Abstract
The unique Kimmeridgian-Oxfordian complex of unconventional and fractured carbonates has been tested to be prolific producer of gas, condensate and light oil in different wells discovered in various North Kuwait fields. The challenge is to characterize the complex reservoir flow system where critical reservoir parameters such as reservoir type, porosity and permeability characteristics, and production and pressure data can vary substantially.
The relationship between the natural fractures and the tight matrix in controlling effective system conductivity in reservoir flow units are the key features which dictate the nature of inflow mechanisms thus the production performance. The paper deals with developing an effective methodology which integrates the variations in critical reservoir properties of the low porosity yet naturally-fractured carbonate reservoir.
The drill stem test (DST) results in some wells were successful without stimulation, while in other wells the DSTs were unsuccessful in spite of advance and repeated stimulations, thus categorizing these plays as geologically-complex, tight gas condensate reservoirs where out of ordinary stimulation techniques may be needed to activate the fractured matrix. Pressure transient analyses and flow regime interpretation of the successfully-tested wells confirm the dual porosity flow-system and the fractured nature of the reservoir.
In this paper, the authors will discuss a new integrated approach for understanding the production and pressure behavior in light of the unique unconventional reservoir characteristics along with the fractured reservoir properties. Dual-layer and dual poro-perm models for pressure transient analysis have been applied extending the previous study of relationship developed between the productivity index (PI) and the total organic carbon (TOC). The proposed integrated methodology can significantly improve the current approach to production optimization, reservoir management strategy, completion, and stimulation design in fractured tight gas condensate reservoirs in Kuwait as well as in other regions.
Evaluation of Sand Screen Performance using a Discrete Element Model
Authors: Feng Yuqing , Choi Xavier , Wu Bailin , Wong Chong 
Published: October 2012

Abstract
Sand screens, including wire wrapped sand screens and slotted liners are often installed in sanding prone wellbores to control sand production. The selection of optimal sand screen aperture for a given sand body is critical to minimize sand production while maintaining well productivity. Laboratory sand retention tests were developed over 10 years ago to provide a basis for sand screen selection. Unfortunately, these experiments have a number of limitations. For example, the results can be substantially different depending on how the tests are conducted and data interpreted. This can lead to different (sometimes wrong) sand screen types and screen opening size recommendations.
This paper presents an initial investigation of the sand production problem from wire wrapped screens and slotted liners, through the use of discrete element model (DEM) for the solid flow with or without fluid flow coupling using computational fluid dynamics (CFD). The focus is on some key design and/or operating parameters affecting sand retention over the sand screen, such as the screen opening size, initial solid concentration, fluid flow velocity as well as particle shape.
Pushing the Envelope of HT Drilling Fluids: Development and Field Applications of a Novel Non-Aqueous Drilling Fluid in the Gulf of Thailand
Authors: Charnvit Kerati , Kongto Abhijart , Huadi Fransiskus , Sharma Sunil , Simon Gerard , Estes Brent , Trotter Neil 
Published: October 2012

Abstract
Typical wells in the Gulf of Thailand are drilled using a slim-hole design that requires 6⅛-in. hole for their reservoir interval. The slim and highly deviated well geometry, potential of high acid gas contamination, and high-temperature environment requires a well-engineered non-aqueous drilling fluid (NAF) to meet the overall well objectives. These conditions always place severe limitations on the drilling fluids design and often lead to failures in openhole wireline logging operations, which is the most important well objective.
The key fluid properties to ensure the success of wireline logging operations under this high temperature are high-temperature, high-pressure (HTHP) filtration control, filtercake quality, and thermal stability of the drilling fluid under extreme static condition. Selected emulsifier and HTHP filtration control agents work synergistically in providing excellent hole condition which allows the hole to be fully logged and evaluated. Clear benchmarks were set and monitored in all the field applications: (1) Successful wireline logging operation; (2) Variation of mud weight after static condition; (3) Variation of mud weight compared to formation tester data point.
This paper details the design, development, and field applications of an ultra-high-temperature NAF used for drilling deep and hot wells in the Gulf of Thailand. In addition, the extensive laboratory work required to optimize the formulation for extreme high temperatures, the lessons learned, and the critical engineering guidelines for running a NAF in such harsh conditions will be described.
Predicting the Arrival of an Interference Response in a Direct Communication Test
Authors: Fair Chris , Goldsberry Fred 
Published: October 2012

Abstract
The purpose of this paper is to provide a more relevant solution to the diffusivity equation than the conductive disc/zero potential flow (Exponential Integral) solution, especially for use in predictions of the time that is required for an interference effect to reach an observation well. After explaining the assumptions and theory behind the method, a direct integration of the radius of investigation will be presented, along with a physical explanation of what it is. While presenting multiple examples to support the theory, the results from Exponential Integral method for predicting interference arrival at an observation well will be compared. Finally, it will be demonstrated that the classic radius of investigation equation is more appropriate in interference/communication testing, and that rate, gauge resolution, and the total system pressure drop do not affect the arrival of the interference effect.
A Methodology for Reducing Bias in the Design & Evaluation of Hydraulic Fractures
Authors: Newman S. , Fair C. 
Published: October 2012

Abstract
The purpose of this paper is to present a framework to reduce bias in the design and evaluation of hydraulic fractures. When we mention "bias", we are referring to human nature. If someone knows what the answer is supposed to be (what someone else wants, or to provide a consensus), they are much more likely to provide that answer - even if it is not correct. In addition to frac design (and re-design after pre-frac tests), this process will be extended to the process of post-frac evaluation and the analysis of the frac flowback and other well tests. The process consists of three parts, to be done in isolation from each other. The first is the actual frac design. This includes the gathering of the geo-physical and reservoir property information, the creation of the geo-mechanical model, the selection of equipment, and the execution design to meet the operator's objectives. It also includes any re-design required based on DFIT/minifrac analysis, performed prior to the frac. The second part is the review of the fracture operation, often called the Frac Replay. This is where the actual field data (rates, pressures, concentrations, etc.) and geo-mechanical model are used to simulate the pad and proppant placement and concentration in the fractured interval. The final part is analysis of the frac flowback, as well as any subsequent well tests. If designed and executed properly, the flowback/well test data can provide an independent validation of the effective fracture length, fracture efficiency and drainage radius/volume.
The reason for performing these three parts in isolation is that it utilizes service companies, consultants and in-house experts to the operator's advantage. If they are not performed independently, the answers are highly susceptible to a forced consensus, especially if the party doing the design or performing the frac job wants to demonstrate the effectiveness of their work. If the results of all three independent parts point to the same conclusions, the operator has more confidence in the outcome. If not, the differences can be examined, with an eye to improving future designs and executions.
Renewal Plan: Efficient Strategy for Optimum Development in Mature Fields – A Success Story from Sanga-Sanga Assets, Indonesia
Authors: Wijanarko Andre , Ismanto Bambang , Permana Robhy , Pizzolante Italo 
Published: October 2012

Abstract
VICO Indonesia is the operator of the Sanga-Sanga Production Sharing Contract located onshore of the Mahakam delta, East Kalimantan, Indonesia since 1968. Over 40 years the PSC has produced 70% of the estimated original gas in place, supporting Bontang LNG plant. VICO has 7 producing fields, in a complex fluvial deltaic deposition with more than 2700 gas and oil reservoir, mixed of depletion and water drive mechanism reservoir. VICO production peaked at 1.5 BSCFD in 1995 then start to decline. Current production is in the range 385 MMSCFD of gas and 14500 BOPD of liquids from 400 active wells.
In a situation of 46% annual base decline, to fulfill domestic and LNG contractual commitments and to optimize reserve recovery, VICO generated and implemented an integrated and aggressive work program called "Renewal Plan". This is an integrated approach between reservoir management and technology application; it provides a detail road map to onward development strategy.
The main elements of the plan are extensive development drilling activities (conventional drilling, grid base drilling, cluster well drilling), low permeability reservoir optimization (horizontal well, hydraulic fracturing, radial drilling), production optimization (deliquification technique, permanent coil tubing gas lift for monobore type) and facilities optimization (reducing abandonment pressure by additional compression installation, wellhead compressor, debottlenecking).
Technology application in drilling, completions, production and facilities optimization combine with synergy from multidisciplinary team have resulted in maintaining VICO production decline in the range of 5% (vs 46% base decline), allowing promoting and partially replacing the reserves at an attractive development cost, even after 40 years production life.
This paper will describe the successful implementation of renewal plan in VICO Indonesia, which proved to be an efficient example of better reservoir management for optimum development of mature assets.
Formation Damage in Geothermal Wells (Salamander field case)
Authors: Bedrikovetsky P. , You Z. , Badalyan A. , Hand M. , Matthews C. , Jenson D. 
Published: October 2012

Abstract
A new mathematical model for flow towards the well during water production from geothermal reservoirs accounting for fines mobilization, migration and clogging of production well is developed. Treatment of the well discharge data from geothermal reservoir A (Australia) exhibits good agreement with the results of mathematical modeling, which validates the model. The sensitivity analysis based on published laboratory data and theoretical model prediction shows that geothermal reservoirs are particularly vulnerable to fines migration due to reduced electrostatic particle-grain attraction at high temperatures. The modeling shows that large flow rates result in the increased formation damage and productivity impairment.
Lessons Learned from a Water Shutoff Technique for Cross Flow between Two Perforation Intervals in Al-Khafji Field
Authors: Al-Dhafeeri Abdullah M. , Mohammed Tawakel , Moawad Taha M. 
Published: October 2012

Abstract
The excess of water production from oil wells in several areas of Khafji field is a subject of concern for reservoir management. Water shut-off techniques are common practices to reduce water production which is resulted in well productivity improvement. An oil producer well-A, was worked-over on February 22, 2006 to conduct a water shutoff technique on existing perforation intervals utilizing a cement squeeze. Several logs such as RST and Gamma Ray were carried out to identify the fluid movement. Then, the well was produced with an oil rate of 1,200 BOPD and a rapid increase of water cut of 60%. The well was still unstable in terms of rate due to high water cut. The well was considered for rigless work-over to control the water using Mechanical Through Tubing Bridge Plugs (MTTBP) to isolate the lower two perforation sections. After setting the Bridge Plug with 8 ft. of cement above the plug, the well was revived with production stream. During the first 24 hrs of well production, the treatment result was not as expected which resulted in 100% water cut. A discussion was made by reservoir management engineer to continue of production for additional 24 hrs. With time, the well showed a positive result with a reduction in water up to 95%. It is recommended to keep the well to be produced over 21 days with final results showed the well revived with an oil production of 1,500 BOPD with zero water cut.
The result showed a successful water shutoff technique and scenario to retrieve the well with 100% water cut produced after treatment. Challenges, intervals selection, design criteria, lessons learned, and results of the water shutoff technique will be discussed in this paper.