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Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The key point of carbonates horizontal wells acidizing stimulation is how to distribute the acid uniformly in the horizontal section, and the conventional solution is to adopt multistage temporary plugging technology. The regular temporary plugging agent cannot satisfy the requirements of YuanBa Changxin group marine formation due to the ultra deep buried depth and high temperature of gas reservoir. This paper developed an organic fiber temporary plugging agent, which took high viscosity fracturing fluid as transmission medium. Laboratory test figured out that the temporary plugging agent can reduce the permeability of more than 1 000 times, and have well physical plugging effect. Besides, fiber dissolution rate is very high in high temperature and acid environment, which realize zero residues after temporary blocking. Using jet drilling fluid induced by liquid nitrogen to induce flow mud in horizontal wellbore before acidification process, and then multistage plugging alternating injection technology was conducted. The stages number of temporary plugging was determined according to reservoir distribution and liner segments. Temporary plugging fluid and gelled acid were injected by following the method of "the initial low discharge capacity, temporary plugging constant flow, later large volume" to realize the acid distributing uniformly. This technology has been applied in four wells, and the temporary plugging efficiency is up to 80% with 100% stimulation efficiency. The well field results illustrate that the multistage plugging alternating injection technique was more suitable for deep carbonate horizontal well stimulation. [ABSTRACT FROM AUTHOR]

Long lateral-section horizontal wells play an important role in exploiting oil and gas reservoir. Compared with vertical well and general horizontal well, it has unparalleled technical advantages. However, because of some factors such as long lateral-section, complex rock lithology, and long contacting time by drilling liquids or drilling tools and formation, many technical problems rise in the process of drilling and cementing. To raise the drilling level of long lateral-section horizontal wells, the paper summarizes these problems firstly, and analyses the reasons of drilling and cementing difficulties secondly. It concludes that the drilling difficulties of long lateral-section horizontal wells are caused by the long lateral-section, and the cementing difficulties are mainly caused by the status of horizontal-section being vertical or approximately vertical to the gravity direction of pipe and slurry. Finally the paper proposes some measures such as optimizing well trajectory, optimizing the performance of drilling liquids and cement liquids, optimizing drilling and cementing tools, and optimizing the tripping method of casing, which raises the quality of drilling and cementing and brings some guidance on the drilling and cementing of long lateral-section horizontal wells. [ABSTRACT FROM AUTHOR]

Precision screen completion has good sand control capacity, and is suited for horizontal wells with severe sand production. The flow near the wellbore with precision screen is different from that of ideal well in which it includes the radial flow in the distal formation, the convergent flow in slotted liner of the protective layer, the radial flow in intermediate filter layer, and the convergent flow in the hole of the base-pipe. In this paper, the skin factor model of horizontal well completed with precision screen was built up in consideration of formation damage, and an actual computation was performed with this model. The result shows a little difference between the calculated result and actual data, proving the fitness of the model. Through analyzing the sensitivity of the factors, it was found out that the skin factor was largely affected by parameters of damaged formation, the permeability of the intermediate filter layer, the penetration ratio of slits in the protective layer, the slits around the protective layer, the hole density of the base pipe, and phase angle and borehole radius. [ABSTRACT FROM AUTHOR]

The current level of horizontal wells fracturing is simply with single well, and the impact of water injection and well patterns are often neglected in enhancing the capacity of single fractured horizontal wells, which appears serious limitations in fracturing effect. Aiming at enhancing the whole block of the recovery, taking the whole reservoir as study object, this paper established an overall fracturing theoretical model for horizontal wells. Fully considering combined distribution of horizontal and vertical wells, a variety of well patterns containing horizontal and vertical wells were designed, and an optimizing design software for horizontal well fracturing was developed. Based on optimizing the well pattern of horizontal wells overall fracturing, considering different length of horizontal sections, the parameters including numbers of fractures, fracture length, conductivity, crack spacing, crack asymmetric distribution and so on were designed, and then the optimal crack parameters have been obtained to forecast the production performance of fractured horizontal wells (daily production, cumulative production, rate of water content, recovery percent of reserves and so on). The method and software would provide certain reference on enhancing the horizontal wells overall fracturing effects. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, multi-branch horizontal well has become the most important well type for coal bed methane(CBM) development because it can effectively enhance CBM production. But lacking skill and experience often cause slow drilling, sticking accidents, and other complex situations underground. The paper makes a comprehensive analysis on the trajectory control difficulties at each stage of multi-branch horizontal well drilling, and gives build-up section track design operation process. Through selecting a reasonable MWD system, the trajectory parameters of the whole drilling process is precisely controlled. The article also explores pending sidetracking, old well bores reentrant technical difficulties and control points. It provides reliable technical reference and accurate referencing data for drilling coalbed methane multi-branch horizontal wells. [ABSTRACT FROM AUTHOR]

Sulige gas field belongs to three low-fields, including low porosity, low pressure and low permeability, and requires fracturing treatment for industrial gas. Depending on its technical advantages, coiled tubing jet perforating staged fracturing through annulus technique becomes the most significant method for horizontal wells stimulation in Sulige area. Through the combination of down-hole tools such as positioned and packer, coiled tubing jet perforation separated fracturing through annulus technique can realize sand blasting perforation, packer stratification, downloading casing in large quantities and coiled tubing accurate positioning. So several works can be finished by only one string trip, and has the advantages of short working cycle, low cost, full size after fracturing, etc. This paper elaborates the operating principle of this technique and the mechanism and structure of main tools in detail. The successful implement of this new process in one horizontal well in Sulige illustrate that the coiled tubing jet perforation separated fracturing through annulus technique is applicable to tight gas reservoirs, providing a new and effective mean for multi-stage hydraulic fracturing of horizontal wells. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Generally speaking, the horizontal section length of Dual horizontal SAGD wells is longer than that of conventional thermal recovery wells. During the production process of SAGD section, it is prone to steam channeling between production horizontal wells and injection horizontal wells and reserves non-uniform used in the horizontal section, which affect the development performance of SAGD well groups and increase the controlling difficulty. In order to improve the uniformity of producing degree in horizontal section, a uniform steam injection theoretical model was established and corresponding pipes were design in this paper. Trial test in the Feng City SAGD has obtained remarkable results, which is useful to future SAGD expand application. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Yong'an block of Shengli Oilfield is a typical small complex fault block oil reservoir. In order to explore the potential of this kind of reservoir further, a cross-block ladder horizontal well is used on the basis of recognizing faults, and the remaining oil in different faults is produced by one well. By this method, the recovery is improved and the drilling cost is decreased. The paper analyzes the reservoir characteristics of Yong'an block and illustrates the difficulties for drilling and completion of this well, on the basis of which it introduces the drilling and completion techniques of the first cross-block ladder horizontal well of Shengli Oilfield, Well Y3p9. Geosteering technique and seismic cross section are combined to determine the fault location and to accurately control the well trajectory to pass through faults and dig into another oil layer. Drilling and completion integrated technique and plastic micro-expansion slurry are taken to greatly increase the cementing quality of ladder horizontal wells. This well has been successfully drilled and produced, which proves the cross-block ladder horizontal well can improve the recovery ratio of fault block reservoir, and has promotional value. [ABSTRACT FROM AUTHOR]

Optimization model of ICD in horizontal wells coupled with the reservoir and different types ICD computation model of pressure difference were built in this paper on the basis of analyzing the flow process of fluid from layers to wellbore under the condition of well completion design with ICD in horizontal wells. And then, static simulation parameters design method and dynamic simulation parameters design methods of ICD in horizontal wells were studied, and then the characteristics, differences and operation of these two types design methods were elaborated respectively. On this basis, optimal design about ICD in horizontal wells was figured out by combining both the static and dynamic stimulated parameter design methods. The feasibility and applicability of model and optimal design method of well completion with ICD in horizontal wells were verified by example calculation and analysis. These study results provide some theoretical basis for optimal design about ICD of horizontal wells. [ABSTRACT FROM AUTHOR]

A steady state coupling model combining seepage flow and pipe flow was established for herringbone horizontal well, which will provide fundamental theory reference for completion design of complex structure wells. This model focused on open hole completion system and was solved by infinitesimal section method. Each part of pressure drop in coupling flow with existence of completion screen pipes was discussed in detail, and then the flowing pressure and flow rate distribution profiles were given. The analysis results show that, formation sand stack layers in annular space between screen pipes and wellbore produce an additional pressure drop, which make a negative influence on the seepage flow. The flowing pressure and flow rate distribution profiles of wells with screen pipe are lower than those of open hole under the same flowing pressure, and the affection degree primarily depends on sieve size of screen pipe as well as formation sand grain distribution, and partly controlled by local seepage interference. The size of screen pipe, parameters of eyeholes in base pipe and mass transfer in pipe wall have an effect on well bore flow, which makes wellbore flowing pressure distribution profile of overall production section is steeper than that of open hole under the same proration production. By comparing the calculated results with the classical model solutions, the model proposed in this paper is proved reasonable. [ABSTRACT FROM AUTHOR]

Inflow Control Devices(ICD) represents a new well completion technology for controlling bottom water which provides uniformity of the inflow profile by restricting high specific inflow segments while increasing inflow from low productivity segments. This paper studys with numerical simulation the effects of the proportion of high permeability zone, permeability grading, the length of control section and the flow rate of control section on the water breakthrough performace of a reservoir with bottom water using ICD,and determines the optimum placement of inflow control device, the flow resistance rating and the length of control section. The results show that the smaller the proportion of high permeability zone is and the larger permeability grading is, the better the water breakthrough performace of a reservoir with bottom water is in heterogeneous reservoirs, and ICD mounting location, length and limit flow rate have an importantment of water breakthrough performace of a reservoir with bottom water. In order to make the water control and oil increment effect maximization, ICD should be installed in horizontal well section of high permeable zone, and the length must be equal to or slightly higher than the high permeable zone length. The flow rate in the high specific inflow segments shold be as close as possible to the average flow rate in all sections. [ABSTRACT FROM AUTHOR]

Acid-cleaning technology of screen completion horizontal well is an effective measurement for cleaning the drilling fluid pollution in bore hole, and the acid-cleaning effect directly affects the well productivity. The early stage of acid-cleaning strings in Shengli oilfield has some deficiencies such as incompletely sealed well-washing valve, poor sealing effect of well washing packer and no drainage channels. Such problems directly caused poor acid-cleaning effect on horizontal wells. The acid-cleaning strings were specific modified and the sealing structure of washing valve was improved in this paper. And then well-cleaning packer equipped with flow path was developed. The new technology improves acid-cleaning performance and effectively enhances well productivity of screen completion horizontal wells. [ABSTRACT FROM AUTHOR]

Compared with vertical wells, horizontal well fishing operations are more difficult, high cost and taking the risk of well abandoned. For this case, high-intensity dropping control unit for horizontal wells in ultra-low permeability reservoirs was developed, which is specific suitable for horizontal well structure. The device structure, technique principle and technical features of this unit were introduced in this paper, and then the anchoring strength was theoretical calculated and performance index was studied in lab tests. Theoretical calculation and repeated laboratory and field tests show that the device has a good adaptability to the downhole and anchor effect, which can basically meet the production requirement of horizontal wells in ultra-low permeability reservoirs. The device has a feasible principle, logical structure, reliable performance and could be widely applied. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)