bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling of an Ultra-Deep Exploratory Well - Problems and Solutions: A Case Study
Authors: Chen Peng , Cheng Cunzhi , Xin Junhe , Wang Xi , Ye Dongqing , Feng Guoliang 
Published: July 2012

Abstract
This paper presents a case history on drilling of an ultra-deep exploratory well with a lot of problems and final solution in a complicated K structure in Uzbekistan. Drilling troubles include serious stuckpipe resulted from drilling-in the unexpected high pressure brine formation, malfunction of the high density drilling fluid system, and subsequent failure of the fishing jobs, unsuccessful sidetracking, bad job of cementing, etc.
After the drilling fluid system was improved, the high pressure layers were isolated, and the proper drilling measures were carried out, the second sidetracking gained success and the well was completed. Afterwards, an adjacent ultra-deep well in the same structure was smoothly drilled and completed by means of optimization of the casing programs, drilling fluid system and technical measures.
Drilling practices of previous offset well indicated that the formation is pay zone and produced oil, while the same formation at the same depth in the well JD3# produces brine water, which resulted in overflow during twice sidetracking of the same formation. The high and low pressure layers existed in the same section after drilling-in brine formation would produce complex against drilling and subsequent operations, therefore a 7-inch liner was set to isolate the high pressure formation, so as to create a good condition for deeper drilling operation. High-density drilling fluid with good precipitation stability and lubricant anti-sloughing properties also contributed to the success in drilling of high pressure brine layer and salt gypsum formation.
Accurate determination of the must-be-blocked point is the key to the success. Drilling of the well with problems and its final solution could be used for a technical reference as drilling in deep or ultra-deep wells in similar geologically complicated oil and gas fields.
Application of Water-base Semipermeable Membrane Drilling Fluid Technology in Sebei Natural Gas Field
Authors: Wu Jinxing , Li Xiucun , Liu Youcheng , Fan Zuoqi , Dai Dengzhi , Li Xiaojun , Wei Xihai , Wang Fengming , Chen Hua , Zhang Xiaoguang , Zhang Haiyang , Tang Bao 
Published: July 2012

Abstract
This paper introduces the application of new technology on water-base semipermeable membrane drilling fluid in Sebei Natural Gas Field. Experiments relating to low rate of mud yielding, rate of recovery for drilling cuttings and antipollution, etc. have been evaluated the performances of this drilling fluid, indicating a high semipermeable membrane performance, strong inhibition of shale aquation, expansion and dispersancy, good resistance of pollution by cuttings and high-temperature rheological behavior. In Sebei Natural Gas Field, the application of the drilling fluid shows the good performances as above said as well as prevention of borehole collapse, low wellbore expansion rate and borehole is regular.
Simulating Experiments of Hydrajet Perforating Process
Authors: Hu Qiangfa , Zhu Feng , Lv Weiping 
Published: July 2012

Abstract
Experimental researches introduced in this paper combined the fracturing technology, which was needed in Chang-6 stratum of Changqing Oilfield, were carried out with full-size and holo-authentic. and used field jetting tools, parameters and equipments to simulate the process of hydrajet perforating and fracture initiation. All of these were different from the previous.
A real-hole shape and crack structure of the near-wellbore were obtained while dissection 9 experimental samples by special tools.
The experiment results shown that: The whole jetting hole is tear-drop shaped, including four parts: casing perforation, entrance sputtering section, cement necking section and main section. When fracture initiates, a slim channel with gladiate shape is extended in the end of the hole. Secondly, the sample will fracture when jetting velocity is high enough under test condition. It indicates that pressure in jetting hole increases obviously when jetting velocity increases. Thirdly, jetting flow erodes out a slim channel along crack propagate direction when fracture initiates, which increases the jetting hole length doubly and enhances the penetration efficiency. Finally, six individual channels are connected by crack when fracture initiates. It indicates that jetting channels can guide the crack initiation and extension near the well bore under the test condition.
The results of the simulating experiments could be used as the design reference when jetting and fracturing in the similar stratum.
The Drilling Fluid Technology for the Top Formation in South Los Tan Blocks of Turkmenistan
Authors: Baojun Li , Lihua Gao , Changning Wang , zhipeng Lin , xiaobin Yang , Zhao Xiangyang , Changgeng Zhang 
Published: July 2012

Abstract
Engineering incidents frequently happened at the top formation of natural gas exploration wells and development wells in south Los Tan blocks of Turkmenistan, one of the reasons is the difficulty of conditioning drilling fluid technology. By laboratory studies & evaluations and field applications, strong inhibitory polymer and polysulfide drilling fluid used at Well's section I and section II to overcome the problems, which are included poor diagnostic grade, clay stone, unconsolidated cements for sand and clay stone, high clay content (more than 50%), serious mud-making, bit balling, sloughing and shrinking of hole, etc completely meet the need to drill big hole(26" and 17-1/2") in long open hole, as well as to deal with the downhole complexities for a long time(the longest up to 4 months) in TD 3700m wells, and they ensured the downhole's safety, made the logging and running 13-3/8"casing in long open hole with one time successful.How to achieve the performance were discussed as conclusion, for instance, polymer glue for earlier stage, polysulfide for later stage, removing useless solids effectively while highlighting inhibition, reducing dispersing agent as low as possible, keep good rheological property and carrying cutting capability, etc. These are important to process the drilling fluid, and build a a technological package of drilling fluid for the top claystone formation of natural gas well with big holes and long open hole, in south Los Tan blocks of Turkmenistan. This drilling fluid system improved the exploration &development technology in South Los Tan blocks of Turkmenistan, which well guide and offer support to explore big hole and long open hole in clay stone formation.
Multistage Pulse Deep Penetrating Perforation Technology
Authors: Weishan Zhang , Zhaohui Wang , Fengchun Liu , Guo Yang , Shuhua Wang , Yang Jing 
Published: July 2012

Abstract
This paper describes the effect of this technology on perforation and production increase mainly in three aspects, namely, the principle, technical characteristics and application. Field application in over 200 wells has demonstrated that multistage pulse deep perforating penetration technology is a safe and reliable perforating technology, for its utilization in an oil production well can improve the capacity, and in an exploration well can reduce leakage in the oil layer. This technology is a new perforating technology in the 21th century, which has overcomed the shortcomings of combined perforating technology and the deep- penetration jet perforating technology respectively featured by a low gunpowder load and single increase of penetration depth. It is a rational combination of jet perforating and gunpowder fracturing, with which three processes including jet perforating and two gunpowder fracturing operations can be accomplished in one running. Thus the compaction zone in the perforation channel will be crushed, and several radial and vertical cracks will be formulated around the hole to communicate natural cracks in the formation. Then the target of deep penetration into the damaged zone in near wellbore formation and improved flow conductivity of near wellbore formation will be realized and eventually the oil well capacity will be promoted. This paper is to introduce a new perforating technology, namely, the multistage pulse deep perforating penetration technology.
The Effect of High Pressure and Temperature Variation to the Hydraulic of Dual Gradient Drilling Operation
Authors: Marbun Bonar Tua , Adi Kurnia Hafiz 
Published: July 2012

Abstract
The petroleum industry is demanding new drilling concepts that make exploitation of deepwater resources economically feasible. Dual gradient drilling concepts have been introduced to overcome the challenges associated with deep water drilling, by providing simpler, safer, more economic well designs and therefore increasing the ultimate development and utilization of deepwater resources14.
In dual gradient drilling, the wellbore is drilled with two different annulus fluid gradients in place. By having two distinct pressure gradients, a favorable pressure profile in deepwater wells is expected specifically a profile closer to what naturally exists in the subsurface formations. This causes the utilization of dual gradient drilling will reduce the number of casing strings required, reduce the non-productive time and also enhances well control7.
Even though dual gradient drilling provides a system that makes the pressure profile closer to what naturally exists in the formation, the pressure across the annulus is also affected by changes of pressure and temperature over depth, as both of changes will affect mud density and its rheology. The study of the effects of pressure and temperature variation is required to understand the distribution of mud density and rheology over the depth and to ensure that the dual gradient drilling operation is able to be conducted in a safe manner.
As dual gradient drilling introduces additional circulation and injection lines, the calculation of injection fluid flowrate-based on the minimum flowrate required to lift the cutting to the surface-, bit hydraulic optimization and the injection fluid density-based on required pressure profile across the wellbore-is very important, since failure in determination of those parameters will cause hole cleaning problems, inefficient drilling operation, or even kick and lost circulation problems.
This paper presents a detailed hydraulic analysis of a Dual Gradient Drilling operation, which uses a liquid and gas-lift system and provides the determination of cutting transport parameters, hydraulic optimization, required injection fluid density, required injection fluid flowrate, and the pressure profile due to different annulus fluid gradients in place. To achieve an accurate determination of hydraulic parameters, a software application has been created and developed. A previous deepwater model that has been proposed by Lopes is used as the input for this software.
Development of a Marine Riser Gas Management System
Authors: Kozicz John 
Published: July 2012

Abstract
Drilling offshore oil and gas wells has become increasingly challenging as water and well depths have increased. In these areas drilling hazards resulting from narrow margins between pore and fracture pressures, pore pressure uncertainty, pore pressure regression, high pressure and high temperature have resulted in significant additional cost due to the time required to rectify problems associated with these hazards. As a consequence, industry has focused its efforts on developing mitigations to these challenges. Typically these developments have tended to focus on down hole solutions such as Managed Pressure Drilling and Dual Gradient Drilling; developments in drilling fluid management technologies and wellbore strengthening etc.
One area which has not received as much focus recently is that of managing the drilling process and in particular the unique aspects relatedto working in deep water from Mobile Offshore Drilling Units. In particular theprobability of relatively small undetected hydrocarbon influxes abovethe subsea BOP.
Depending on the drilling fluid and influx composition, unconstrained expansion of the influx (gas) may exceed the surface equipment handling capability (i.e. diverter system, capability and performance). Additionally, depending on the bubble pointof the drilling fluid / influx composition unconstrained evolution of fluid fromthe riser can result in a significant reduction in riser fluid level and thereforereduction in hydrostatic pressure which may impact the riser BOP system as wellas increase the probability of additional influxes entering the wellbore.
This paper describes the design, development and construction of a riser gas managementsystem which addresses these concerns.
New PDC Bit Technology Significantly Improves Performance in Hard Abrasive Bashijiqike Formation Iin China
Authors: Botton Benoit , Sha Dennis , Yinglin Jia , Guoyu Jia , Jian Zhou , Baitao Peng 
Published: July 2012

Abstract
Drilling the 6-5/8" vertical sections in the Tarim oilfield, in China's western Xinjiang Uygur Autonomous Region is challenging. The sections are a very hard and abrasive formation, typically a 300m interval starting at a depth of 7000m. The Cretaceous Bashijiqike formation consists of layers of quartzitic fine sandstone (35% quartz) and silificatedclaystone with conglomeratic sandstone stringers both at the top and bottom of the Section. Low rate of penetration (ROP) and short bit runs are typical for drilling this formation. With bottom hole temperatures at 148°C and mud density around 1.9sg, the application of roller cone bits and downhole tools with moving parts is limited.
Historically the section has been drilled with a simple rotary BHA consisting of a bit, 468m of 5-inch spiral drilling collar, 2565m of 4-inch drill pipe and 5-inch drill pipe to the surface. Bits used have been a variety of locally sourced 6 bladed matrix PDC bits with cutters from 8mm to 16mm. the average interval per bit was 30m at 0.47m/hr.
The increase in PDC bit performance was very critical to the overall improvement of drilling efficiency and economics in this application. A target of 50m interval at 0.5m/hr was set for the development of new PDC drill bits.
The new 6 bladed bits, using 16mm and 13mm cutters respectively, exceeded the objectives. This success is a combination of in depth analysis of the application and past performance, use of new high abrasion and impact resistant cutters and optimized cutting structure design. In the first well the new bits drilled 206% further and 62.7% faster than competitor bits used at shallower depth in the same well. On the second well, the new bits outperformed competitors by 159% on interval drilled and 38% on ROP.
The Application of Horizontal Well Coiled Tubing Frac Technique in the Daqing Oilfield
Authors: Li Lin , Wang Fengshan , Liu Chongjiang , Xu Dekui , Ji Haibo , Ban Li 
Published: July 2012

Abstract
The dominant horizontal frac technique is the sectional frac technique with dual-retrievable packers in the Daqing Oilfield, which adopts the small diameter dual packers to stimulate the targeted formations one by one. For several intervals treatment can be done in one trip, reverse sand flushing and pulling the tubing upward fulfill the frac operation. The well-head equipments need to be assembled and disassembled repeatedly and pulling the tubing upward can lead to the low job efficiency, intense labors and high risk of well operation when fracturing multiple formations. The coiled tubings were introduced in the Daqing Oilfield, which were integrated with the sectional frac technique in the horizontal wells to take advantage of the coiled tubing and improve the frac efficiency. Five aspects were researched as follows: The redress kits of the coiled tubing were developed to match the dual-packers frac tools; Anti-blowing equipments on the well head were researched according to the whole length of the frac tools; The resistance of the coiled tubing and filmed proppants’ tests were researched to optimize the reasonable frac parameters; The assemble test between the coiled tubing and the conventional tubing widens the application of coiled tubing.
Up to now, the coiled tubing frac technique has been applied on 3 horizontal wells in the Daqing Oilfield, among which 5 intervals were fractured in Well A. The time of tubing pull upward saved more than 1 hour to improve the rig efficiency, reduce the worker’ s labor and lower the risk of well operation. The coiled tubing frac technique indicates a step up in the field of shallow horizontal well fracturing.
Refinements to Cutter Technology and PDC Bit Hydraulics Lead to Faster Drilling in Hard/Abrasive Formations, East Texas
Authors: Zhang Youhe , Douglas Charles , Mueller Levi , Shen Yuelin , Likki Srinivas , Bits Smith 
Published: July 2012

Abstract
Drilling the hard/abrasive Travis Peak/Hosston and Cotton Valley formations in East Texas/North Louisiana creates a distinctive challenge for polycrystalline diamond compact (PDC) bits. Conventional PDC cutters fail quickly due to abrasive wear/spalling and/or delamination of the diamond table. Most bits are typically pulled in poor dull condition graded 1-2-WT or worse. The situation has caused stagnation in PDC performance and limited additional gains in total footage and rate of penetration (ROP). Recent scientific studies have indicated that thermal fatigue of the diamond table is the main contributing factor leading to cutter failure and is restricting further advancement of PDC drilling in East Texas and other hard and abrasive applications. To improve cutter performance the industry must:
Manufacture a cutter to resist abrasive wear and retain a sharp edge for an extended amount of footage Reduce/maintain temperature at the cutter edge to minimize thermal fatigue
To accomplish the objectives, engineers refined and implemented several new processes to increase abrasion resistance and maintain temperature at the cutter tip. This technology platform includes:
Enhanced High Temperature/High Pressure (HTHP)sintering process Refined post-pressing process to improve thermal stability Optimized hydraulics to maximizing cutter cooling
In laboratory experiments, the next generation O2 cutter has demonstrated approximately 15% improvement in resistance to abrasive wear compared to the previous generation of premium cutters (O1). Laboratory tests also confirm that optimizing cutter cooling has enhanced the life of the new shearing element. In East Texas field tests, PDC bits equipped with the new cutter and optimized hydraulics have achieved an average ROP increase of approximately 25% while producing improved dull bit condition. These new technologies are expected to have a positive economic impact in the East Texas/North Louisiana Haynesville shale play and in other hard and abrasive applications worldwide.
An Innovative Method for Horizontal Well Completion in Tight Shale Gas Reservoirs
Authors: Bai Mao 
Published: July 2012

Abstract
Tight shale gas is considered to be an unconventional resource because it cannot be produced without using the reservoir stimulation method. A new completion method is proposed to maximize the internal-flow surface area created from the injection. To prevent the prohibitive costs of drilling multiple vertical wells from the surface to the targeted depth interval, the multiple vertical tracks are branched from the horizontal well drilled either from the overburden layer or from underburden layer, depending on the formation suitability. The examples presented in this paper reveal the significant increase of internal surface areas when the proposed method is used as compared to the existing methods, such as the multi-stage method.
Using Qualitative Techniques to Constrain Normal Compaction Trendlines: A Methodology for Real-Time Pore Pressure Prediction in Exploration Wells
Authors: Villacastin Paulino F. 
Published: July 2012

Abstract
Methods used in real-time pore pressure prediction can be subdivided into two general categories: quantitative and qualitative techniques. Quantitative pore pressure prediction techniques normally used at the rigsite work with resistivity, sonic, DXC and shale density datasets and involve the use of formulae like Eaton. Qualitative techniques work with ROP, flowline temperature, cavings, background and produced gas, and torque, drag and fill datasets. These qualitative datasets are sometimes combined to come up with new techniques. Confining the analysis to one category without the other severely reduces the chances of success at correctly predicting the pore pressure profile.
In quantitative pore pressure analysis a normal compaction trend line (NCT) has to be drawn to calculate the pore pressure. The problem with drawing normal compaction trend lines is that available literature neglects to inform the reader on how to draw the normal compaction trend lines, how many trend lines are to be drawn and at what angle are they to be drawn. Examples project the simplistic idea that in most instances only one trend line is all needs to be drawn. Experience and the preponderance of drilling events, like kicks and stuck pipe, esp. in areas where minimum data is available point to the fact that compaction history is not that simplistic at all and that there are other factors at play. This now begs the question: How do you know that the normal compaction trendline being drawn, hence the calculated pore pressure is correct?
Incorporating two case studies, this paper demonstrates that qualitative techniques could be used to constrain the normal compaction trendlines that will be drawn in the quantitative study of pore pressure and in the process increase the degree of success in determining the pore pressure regime in real time.
The Path from Vertical to Horizontal Shale Gas Wells
Authors: Stolte Chris , Wu Chris , Carroll Darryrl , Liang Jin , Wang Shiqian 
Published: July 2012

Abstract
Shell China, in partnership with PetroChina Southwest, began exploration of the Fushun Shale Gas Block, completing its first wells in 2011. A campaign was designed to acquire subsurface data in the exploration campaign to assess the Lower Longmaxi Hot Shale interval with an end goal of assessing the feasibility of a shale gas field development in the block. As part of the first phase of the exploration campaign, two vertical wells were drilled and completed followed by three horizontal wells.
Over the execution of the first two vertical wells significant performance improvement was achieved by the service contractors involved in the project, resulting in decreased Non Productive Time (NPT). Significant preparation was conducted in order to prepare both local and international contractors for the horizontal wells in the campaign. In order to deliver the horizontal completions in an efficient manner, the Fushun team implemented learnings gained through similar projects in North America. Preparation for the horizontal well campaign included arrangement of the source water with the local community, ordering new equipment capable of completing the work, cross-posting of service contractors to unconventional assets in the U.S., and movement of experienced site-supervisors to support the Fushun project. The fracture design was also improved on each well in the campaign delivering more proppant per stage, key towards optimizing hydraulic fracturing and maximizing production potential.
Through the initial phase of exploration activities, a shale gas play in the Fushun Block has been confirmed. Operational challenges and technical learnings that were experienced in the initial exploration wells will be carried into the next phase of appraisal.