bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling and Frac Stimulation Waste Management in Unconventional Gas Projects in Sichuan, China
Authors: Zhu J. , Chen J. , de Blok G. 
Published: July 2012

Abstract
Waste management will play an important role in delivering an environmentally sound well. If, however, a project requires the operator to drill hundreds of deep development wells and in close vicinity of communities, waste management even becomes a critical success factor. There is simply no room for error. The drilling and stimulation of these large number of wells will generate large volumes of solids and fluid waste, which must be managed efficiently, strictly controlled and comply with the requirements of local regulators.
Waste generated during the drilling phase constitutes of Water Based Mud [WBM] cuttings, Synthetic Based Mud [SBM] cuttings and WBM fluids, whereas frac flow back water will be the constituent following frac stimulation. To encompass all of these waste streams in an integrated waste management system, the project team of Fushun and Jinqiu [Sichuan, China] initiated a plan to cover waste generation, waste transportation, final disposal process and a waste tracking system as per ISO guidelines and in agreement with the Company's global Health, Safety & Environment [HSE] policy and procedures.
The waste management is divided in two phases. In Phase I the solution sought is to utilize a recycling method in the field to minimize the generated waste volumes. This comprises a disposal waste stream for each waste category. For WBM cuttings, solidification and burial in-situ would minimize the impact on drilling operations. For WBM waste fluid and frac flow back water, in-situ pre-treatment and then transporting these effluents to industrial waste plants has proven to be a workable and efficient solution. In contrast, OBM cuttings are treated as hazardous waste and are incinerated in a hazardous waste disposal plant.
There are a number of challenges to face, such as heavy land transportation, resistance from local farmers in a populated area, meeting the strict and the mandatory requirement from the Environmental Protection Bureau [EPB], whilst at the same time aiming for overall well cost reduction and project delivery. Another limiting factor is the number of qualified local waste disposal vendors in the Sichuan area.
But when there are challenges, there will also be opportunities. This paper aims to focus on these opportunities and will thus home-in on Phase II, currently under development, which comprises a pit-less drilling and stimulation approach, with all waste transported to a dedicated waste plant and waste disposal location.
Successful Application of ESPs in Bohai Bay Development
Authors: Sheridan Ed , Janjua Zia , McRae Jim , Paranji Sanjay , Long Michael 
Published: July 2012

Abstract
In 2002, during front-end planning for a project in China, the operator Anadarko understood that the electrical submersible pumping (ESP) system run life would be one of the critical factors for the project's success.
Therefore, consideration of the complete ESP lifecycle was taken into account. This included design, equipment specification, contracting strategy, installation practices, commissioning procedures, operating practices including optimization and troubleshooting, as well as ESP teardown and inspection.
The challenge was to provide ESP systems that could:
Cover initial low productivity index (PI) / low fluid rates Cover final high PI / high fluid rates Produce heavy oil Meet all the above conditions while keeping the ESPs within their operating envelopes
This drove the concept developed for the ESP design. The principle is still being used more than six years since its first production.
The final design included the following features:
Encapsulated ESPs to assist with motor cooling at lower fluid rates and heavy oil production Pumps with abrasion-resistant technology selected to cover the required large range of flow rates Geothermal-specification motors to allow operation at higher temperatures Comms-on-power down-hole sensors for continuous monitoring and optimization
Since coming on line, ESPs have been installed and operated very successfully in the CFD group of fields and have been exceeding all run life expectations. Of the 110 ESPs operating, the average run life since the start of production is 3.5 years, with 30 (28%) running more than four years and the longest ESP run life so far at 6.1 years.
Hybrid Fracturing Treatments Unleash Tight Oil Reservoirs Consisting of Sand Shale Sequences in the Changqing Oilfield
Authors: Zongqiang Zhou , Lijun Mu , Xianwen Li , Wen Zhao , Xiaodong Wang , Xiangqian Bu , Wenxiong Wang , Peng Pang 
Published: July 2012

Abstract
Low reservoir permeability and pressure are the key characteristics for the tight oil reservoirs consisting of sand and shale formations in the Changqing Oilfield in the Ordos Basin. In these tight reservoirs, regular fracturing stimulation with modest treatment sizes only yields low post-treatment production that cannot meet development requirements. Recent literature is bountiful in the successful developments of tight oil and gas reservoirs, especially from North America. After conducting literature review and learning from the experience in North America, hybrid fracturing tests were carried out in vertical wells, to improve well stimulation effectiveness in the Changqing Oilfield. Hybrid fracturing treatments for these tested wells yielded very good results with production enhancement at approximately 300% folds of regular fracturing treatments in the same reservoir block. Downhole microseismic fracturing monitoring and production analysis techniques were used to evaluate hybrid fracturing performance. In this paper, the ultra-tight oil reservoirs in the Changqing Oilfield were described, and hybrid fracturing treatments applied to the Chang 7 formation were studied with the aid of minifrac analysis, microseismic monitoring and post-treatment production results.
Hydra-Jetting Staged Horizontal Completion via Multiple Sliding Sleeve in Changqing Sandstone Tight Gas Reservoir
Authors: Yonggao Xu , Zhenfeng Zhao , Yajuan Wang , Yanming Zhang , Xu Ma , Kuangsheng Zhang , Xuangang Lai , Changjing Zhou 
Published: July 2012

Abstract
Changqing sandstone tight gas is characteristic of low-permeability and low-pressure, which is difficult to obtain economic benefits without fracturing. A new multistage fracturing technology for horizontal gas well is used in tight sandstone gas reservoirs. The new technology is hydro jetting-based and control the nozzles by opening the sliding sleeve by ball setting. With no need of packers and slugs, the technology realizes the integration of perforating, fracturing and isolation, achieving fracturing multiple stages in a single trip.
Field trials of 64 wells show that the new technology is simple and reliable, which is capable of meeting the requirements of rapid isolation and multi-fracturing in gas wells. The new technology opens another door for multistage fracturing horizontal well of sandstone tight gas and make the reservoirs have economic development potential.
The New Development of Multi-Stage Fracturing Technology of Multilayer Vertical Gas Wells In Sulige Tight Gas Field
Authors: Tianshou Zhu , Gangdan Fu , Yong Ren , Huaguang Zhang , Fenxia Zhao , Jie Gui , Zaiqiang Wang 
Published: July 2012

Abstract
In Changqing gas field, it is very usual that a gas well contains many gas bearing beds, whose property is different with each other. Because of the low formation pressure and low permeability, the nature rate is so small that every well must be treated. However, when treating these multi-layer wells, the conventional separate fracturing is not effective or cost-effective, and needs long time. To make all the beds treated effectively, to improve individual well producing rate and enhance economic benefit, optimizing several kinds of separate layer treatment technology and analyzing the feasibility of commingled producing in Changqing gas field. In 2005, a new completion string has been introduced[1∼5], which is achieved by plugging of the packers and opening of the sand blast sleeve. Using this technology and completion string, three formations can be fractured continuously, but needn't kill well. Firstly, perforating all the three gas layers at a time, at the same time assembling the completion string, then tripping it in the gas well; secondly, launching a ball to make packers set down, and fracturing the lower most layer; thirdly, launching a ball again to open the upper sand blast sleeve so that the upper layer is connected with the tubing and isolated with the sub layer, so the second layer can be fractured. Similarly, and the last layer can be treated like this step. Finally, when all the layers have been treated, unloading liquids of all layers, blowouting and producing. During fracturing, if sand plug happens, it can be solved by reverse washing. The strong point of this technology is that all the processes are made in the same string and needn't exchange string. From 2006 to 2009, the separate fracturing string with packers has been used more than 2000 vertical wells that cover 2 or 3 payer-beddings.
However, there are more and more vertical wells that contain far more than 3 layers, even to eight layers. So it is necessary to develop the separate layer string for fracturing at least 4 layers. This paper describes how to achieve this aim by intrducing new tecnnologies such as TAP fracturing technology, coiled tubing fracturing technology and modifing the initial fracturing string so that eight layers can be fractured with only one trip.
Application of Cluster Well Drilling Technology in Sulige Gas Field
Authors: Zhou Zongqiang , Cui Longlian , Li Jianmin , Zhang Fucheng , Wu Xuesheng , Wang Haige , Ju Mancheng , Ouyang Yong 
Published: July 2012

Abstract
Advantages of cluster well are that the technology can save land resources, reduce development costs. Sulige gas field is a typical low porosity, low permeability and low abundance. The advantages can meet the requirement of developing and constructing a "scientific, harmonious and environmental friendly" Sulige gas field. There are some difficulties in cluster wells drilling operation in Sulige gas field as following: strong abrasive formation, difficult in trajectory control, low ROP and high drilling costs.
To address these difficulties and promote the application of cluster well, the following researches were carried out: (1) Optimization the numbers of wells under different cluster well network conditions. Combined average horizontal displacement, anti-collision, trajectory control and integrated the cost, the number of wells were calculated, analyzed and optimized. (2) Optimization casing profile. Casing section was optimized into the current "straight - slow bulid - hold-slow drop"; (3) Optimization the well trajectory control mode. A practical and efficient directional well trajectory control technology were explored, and BHAs were developed; (4) Individual design PDC bits. " Spiral knife-wing, short outside the parabolic shape of the crown, double cutting structure, spiral gage" structure of the PDC bits were designed for Sulige formation.
Through innovative research and field integration applications, cluster well drilling supporting package technology have primarily matured in Sulige gas field. The drilling cycle of cluster well was reduced by 35%, with 17.4d drilling cycle in 2011; the ROP was improved by 106.1%, with 14.9m/h ROP in 2011. By the end of 2011, total 468 cluster well grops have been completed and 750 hectares land were conserved. Through the application of cluster well drilling in Sulige field, the development costs were reduced significantly. Cluster well technology has become one of the major development models in Sulige gas field.
Research and Application of BH-ATH (Anti-Three High) Drilling Fluid System
Authors: Minli Zhang , Zengyan Tian , Shaoying Xu , Dianbin Dong , Da Yin , Fengjiang Zuo , Changshu Wang , Li Yin , Liang Ren 
Published: July 2012

Abstract
Traditional anti-high temperature, anti-high pressure, anti-high gypsum salt drilling fluid has many technical problems such as difficult rheology control, low solid content capacity, poor pollution resistance ability and large dosage of various additives. As a result, a new "anti-three high" drilling fluid has been developed together with the key additives including complex organic salt (BZ-WYJ-I, II, III), filtration reducer with gypsum salt resistance and high temperature resistance ability(BZ-Redu-I,II,III), anti-gypsum salt viscosifier(BZ-VIS), inhibitive anti-caving agent(BZ-YFT) and inhibitive lubricant(BZ-YRH). The formula of the system is not complicated and easy for treatment. Besides, the system has the features of strong inhibition, 220°C temperature resistance, maximum density up to 2.6g/cm3, saturated gypsum salt resistance and gypsum insolubilization. It has been applied in 23 wells in Tarim oilfield, HuaBei oilfield in China, Madura block in Indonesia, Halfaya block in Iraq with the maximum density of the application wells up to 2.41g/cm3 and the highest temperature up to 206°C. The site application effect is remarkable since the technical problems such as caving, tight hole, gypsum salt pollution, thermal stability in high temperature have been effectively solved without incidents or discharge.
Clean Sand Consolidation Technology Research and Application
Authors: Zhiyong He , Guijun Wang , Susu Cao , Wei Dang , Fengxiang Zhou , Qingjiang Gu 
Published: July 2012

Abstract
With indepth development of each oil field, the demand for well types with special structures takes a trend of gradual rise. This kind of wells are generally complicated in well conditions, thus the requirements for tool performance are high, and the application scope of corresponding support measures shall be expanded. Besides, risks could increase if mechanic sand control technology is adopted and the solution in later stage will be difficult. The new type clean sand consolidation technology has solved the problems which may occur when with traditional sand consolidation technology and products, such as uneven cementation in sand consolidation, severe damage to formation porosity and permeability, low consolidation strength, etc. This paper describes the principle of clean sand consolidation technology and lab study of auxiliary fluid system, especially the principle of pore increasing before consolidation; while also discussing application scope and application prospect of the clean sand consolidation technology by presenting Well NP23-x2219 as an example.
So far, the clean sand consolidation technology has been successfully applied for 18 wells in domestic oil fields. The operation success rate is 100% and the effective rate reaches 94.4%.
The technology not only meets the demand of sand consolidation for initial sand consolidation for oil wells and water wells, but also has an excellent effect on tackling the problems concerning large production pressure difference, heavy oil, sand sticking or burying oil layer with fine siltstones in middle or later stage, which is applicable for multilayer sand control in long well section.
The clean sand consolidation technology employs the philosophy of safety and environmental protection, with extremely small damage to the formation, surface equipment and personnel, which has explored a new thought for development of chemical sand control technology in future.
Complication Circumstance Directional and Horizontal Wells Drilling Technology in Iran
Authors: Chao-hui Fu , Hu Zhao , Zhi-sen Yun , Yu-qiang Tang 
Published: July 2012

Abstract
Directional drilling technology has been applied widely since the last century. Directional tools and directional drilling technology shall be applicable to the different circumstances.Thus it is necessary to improve directional tools and directional drilling technology according to operation experiences.
In Iran, 146 directional and horizontal wells onshore and 16 directional wells offshore have been drilled by DDDC since 1997. Directional well technology have been applied under different circumstances such as in high weight and saturated salt water drilling fluid system, in the conditions of loss with low flow rate or in 26" or 4 1/8" unconventional hole size.
After contant improving directional drilling technology and tools, drilling hours of the directional drilling tools have been increased from 20 hrs to more than 120 hrs, and the maximum have reached 300 hrs in some wells, the directional tools can keep working in the loss condition, and the unconventional hole of directional wells are completed successful. Improving directional tools and technologY according to the different operation circumstances can lead to increased efficiency of drilling.
This paper presents some practical examples of how to improve directional drilling technology and tools under complicated circumstances, which can contribute to great improvements of directional well service performance.
Solving Slow Drilling/Hole Deviation Issues: Modeling Effort Increases ROP by 250% Saving Operator 14-Days Rig Time, Turfan Basin China
Authors: Tao Dong Zhen , Long Jing Zhang , Zhi Lai Bi , Nan Wenza , Zhang Xiao Long , Kang Tom , Downie Simon , Ke Colin , Jun Jim Zhao , Yong Mike Zhang , Liu Xiao Jun 
Published: July 2012

Abstract
The operator must reduce deviation tendencies in the 8-1/2" vertical hole section drilling the difficult J2x formation to efficiently develop gas reserves in Turfan basin, China. The challenge is to maintain near perfect perpendicular hole trajectory from 2400-3500m while drilling interbedded sandy claystone and coal layers. In the worst case scenario, the operator is forced to make several costly correction runs before starting the horizontal production hole. To solve the problems, engineers experimented with pendulum and steerable motor BHAs to maintain wellbore vertically with limited success.
Most recently, Kekeya wells Ke28 and Ke33 required 6-5 bits/trips respectively to complete the 8-1/2" hole section at unacceptably low average ROPs of 1.6 m/hr and 2.4 m/hr. The operator required a PDC/deviation control tool to maintain verticality and increase ROP. To accomplish the objective, the drilling team utilized a rock strength program and a bit/BHA modeling system to investigate several different cutting structures to determine the best blade count and cutter placement configuration. Based on the study, a six-bladed 8-1/2" PDC bit was identified as the best candidate to accomplish the objectives. To mitigate deviation tendencies, a reliable automatic vertical drilling system (VDS) was selected. The reliable VDS tool does not require a MWD logging sub and can be deployed during normal drilling operations including backreaming and shoe drillout.
The new-style 8-1/2" PDC bit was run in combination with VDS on new well Ke282 with outstanding results. The bit/VDS bottom hole assembly drilled the entire 740m section at 7.1 m/hr through the difficult J2x formation in a single run setting a new field benchmark. The optimized PDC bit increased ROP by 250% while reducing trips/bit consumption by 82%. The performance improvement saved the operator more than 14 days of rig time for a total cost savings of $93,000 USD.
Pre-Drill WBS Evaluation: Plane of Weakness and Well Design - A Case Study in the South of Mexico
Authors: Tellez Carlos Perez , Cabrera Jose R. , Balasejus Detlef 
Published: July 2012

Abstract
Borehole instability mechanisms have been studied in oilwell drilling for many years. Rock behavior has been important because drilling complexity and risk increase accordingly, leading to the need of more complete risk assessments in well design. A new need for risk assessment arises in South Mexico where Pemex and Schlumberger have encountered very challenging areas: a depositional HPHT environment with salt presence, faulted formations, and depleted reservoirs resulting in high-risk wellbores.
In strong dipping formations, wellbore instability occurred as a result of planes of weakness. Several events that resulted in stuck pipe due to packing off, losing wellbore sections and downhole tools translated into severe financial impact. Planes of weakness are directly related to the well's trajectory. Developing a method was needed to predict the attack angle - during the design phase. An erroneous appreciation of the instability mechanism could lead to wrong actions, like increasing the mud density without additional considerations, making problems worse.
Using surface seismic readings and attributes resulted in successfully predicting wellbore instability caused by planes of weakness. The signal-to-noise ratio of a seismic survey was enhanced. Attributes were applied to get an improved structural continuity with reliable dip/azimuth results. An innovative methodology to calculate the attack angle from dip/azimuth from seismic and associated risks of wellbore instability was developed. Three wells drilled in a complex structure affected by a compressive salt environment were evaluated and compared to well logs, getting a good fit.
A complete risk assessment includes the calculation of the attack angle, fault mapping, and rock strength. Knowing these allows for a more complete trajectory planning while predicting wellbore instability. Thus, the output provides a valuable tool to predict failure caused by planes of weakness in the design phase, allowing trajectory modification and operational prevention/mitigation measures to avoid catastrophic stuck pipe incidents and achieve a hazard-free well construction.
Innovative Application of Underbalanced Drilling Technology for Deep Drilling in Wuxia Area of Junggar Basin
Authors: Wei Zhang , Xinjun Mao , Hong Yang , Guobin Wang , Yuezhi Wang , Biao Ruan 
Published: July 2012

Abstract
The rock in deep strata of Wuxia area in Junggar Basin is abrasive and with low drillability. Part of the formation sections with abundant fractures, which leads to mud lose frequently. The exploration progress has been slowed down by low drilling speed and accidents. The exploration department of Xinjiang Oilfield Company preferred underbalanced drilling technology on well F8 and A1 on the basis of feasibility analysis of UBD technology in Permian strata. The applications reduced lose circulation effectively and promote the rate of penetration considerably.
Well F8 and A1 used foam and nitrogen as underbalanced drilling circulation medium respectively. The wellbore sizes are 215.9 mm. The rate of penetration in underbalanced drilling sections are quintuple than conventional rotary drilling. It saved more than 20 days in the overall drilling time. The conversions between foam/nitrogen with mud were successfully once only. There was no losing circulation during underbalanced drilling progress.
The successful application of underbalanced drilling technology in deep strata of Wuxia area solved the deep drilling speed improved problems entirely. It reduced mud lose and promote drilling speed. The drilling overall time and exploration cost has also been decreased greatly. The innovation application provides a new method for deep drilling speed improved in this area.
In the passed drilling, the ROP of advanced cone and PDC bits was nearly 0.65 m/h, and the ROP was no more than 0.92 m/h even with turbodrills and impregnated bits. However, the ROP of underbalanced drilling section has promoted several times than conventional drilling. ROP optimizing was substantial versus direct offset wells that experienced quintuple drilling time through the same formation. With this success, the team has accumulated valuable experience of deep drilling for Junggar Basin.