Abstract:

Abstract:The intersected well drilling project for trona solution mining in Turkey covers Beypazari Phase I to VI drilling works and Kazan Phase I to III drilling works with a total of 200 plus solution mining well sets completed. Overseas drilling works involves with many aspects other than technical issues, among them local politics, regulations, customs, exchange risk, ocean shipment, custom duties. In light of the characteristics of overseas drilling projects and the field working conditions, the project office intensified the management of personnel, equipment and material, site operations, safety and risk, and played properly its role of direction, administration and control so as to reduce project risk, increase profit and ensure smooth completion of the project. This paper introduces the management of the intersected well drilling project for trona solution mining in Turkey in terms of personnel organization, equipment mobilization, onsite operations, HSE and risk control; and summarizes some management experiences on overseas drilling projects.

Abstract:Turkey is the first country to extract trona deposit commercially with intersected well sets. The core technology which is employed to make underground connection of the well sets for brine recovery is the intersected well drilling and mining technology developed by China. Compared with conventional tunnel mining, mining with the intersection well sets provide lots of advantages such as less labour intensity, reduced labour cost, environmentsoundness without discharge of tailings. In the past tenodd years, with support of the intersected well drilling technology, China has participated extensively in test and commercial production of trona resources, and made continuous improvement on the mining well set design, orientation tools, BHAs, survey tools; in particular, great achievement has been made in development and application of the magnetic ranging system, with the 4th generation “SmartMag” ranging tool launched into market; meanwhile, the threewell set mining mode has been desgined and implemented. On one hand, intersected well drilling and mining technology has driven the extensive exploitation of trona resources in Turkey to elevate it to a major player in the world soda ash industry; on the other hand, intersected well drilling and mining technology has advanced itself through intensive field application, lifting it to a higher level.

Abstract:Solution mining of Kazan Trona Mine in Turky is realized by the intersected well set, which is formed by drilling of one horizontal well to intersect one or more vertical wells with help of the high accuracy targethitting guidance system. On the basis of the previous longterm experience, the existing drilling techniques and geological characteristics of the mine, a series of innovative drilling techniques have been developed for the purpose of better exploiting the mine, including the strataspecific drilling techniques, the 3D geological model for the mine, the design and application of intersected wells with horizontal branches, the optimization of the horizontal well trajectory design, the setting up of the standard geophysical logging response curves for the ore and nonore ledges, the deviation control methods based on the study on the formation deflecting mechanism, proper combination of various BHAs, the technique to improve control of the horizontal drilling trajectory, etc. A lot of benefits have been achieved by the application of these techniques, such as the improvement of the planned productivity of the mine, reduced well construction cost, enhanced recovery of the trona resources, decreased construction period, raised drilling efficiency, and minimum impact on environment. The innovative techniques can be referred as a guide for the planning of trona or other soluble mines, and for the construction of intersected well sets.

Abstract:The industry standard “Technical Specification for Directional Drilling (DZ/T 0054-2014)” was formally implemented in December 2014. This standard is the revised version of “Technical Regulation for Directional Drilling (DZ/T 0054-1993)”. This paper mainly introduces the main technical contents and technical characteristics of the revised specification after absorbing the latest practical results of directional drilling technology, as well as promotion and application of the specification in “the Belt and Road” countries after its publication. It is recommended that relevant practitioners should understand and master the clauses of the new standard, and implement them so as to promote the standardization of directional drilling.

Abstract:As the Beypazari Trona Mine in Turkey turns into its middle or late period of mining, plenty of well units situate at the edge of the mine area, where the trona bed is thin and its boundary is highly variable. While drilling horizontal intersected wells at this area with conventional gamma logging system, it is very difficult to ensure that the trajectory of the well to be remained at the trona layer, and the well sets were frequently blocked, or even abandoned during the process of solution mining. The newly developed azimuthal gamma LWD system, by adding focused gamma logging probe into conventional MWD instrument, is capable of recording gamma data of different window angles, to obtain gamma data of the specified orientation. The data is transferred from downhole to the receiver at the surface via mud pulse and processed. By comparing the gamma data at top and bottom direction, it can be determined that the drill bit is about to enter the ceiling or floor of the trona bed. This is an important information for the MWD engineer to adjust the tool face of directional instrument in time, to ensure the ratio of the trajectory within the trona bed. Besides its application in the workover the blocked well sets, the technology could also be applied directly into the newly constructed horizontal wells. With the utilization of this technology, the occurrence of well set blockage is dramatically decreased.

Abstract:Beypazari Trona Mine is one of the two trona mines discovered in Turkey. Now the solution mining area has reached the boundary of the mining area. In order to maximize the recovery of trona resources under the standard conditions, it is necessary to arrange horizontal intersected well sets at the boundary of the mining area to mine the trona out. The geological conditions at the boundary of the mining area are complex with many folding and fault zones located in the study area of this paper. In the early drilling period, it is found that there are obvious geological anomalies in this area, such as pinching out, Vshape, or irregular and high dip angles of the primary mining layer. In view of these typical abnormal problems in drilling of intersected well sets at the boundary of the mining area, several technical measures, such as the casing section milling technology, directional drilling with azimuthal gamma tools and SmartMag targethitting systems, increasing the number of the exploration wells are adopted and all the problems have been resolved efficiently through these measures.

Abstract:Multi-lateral well drilling is the extension and development of horizontal well drilling and an effective tool for improvement of oil and gas recovery and economics. It is widely applied in oil and natural gas exploitation, but rarely in soluble mineral production. In this paper, the application of the technique in trona mining is introduced in the case of H032 well drilling at the Kazan Trona Mine. With the help of directional drilling technique, two parallel horizontal laterals were drilled from one main well bore to connect two pairs of vertical wells respectively to form 2 mining passages. The difficulties in applying the technique in the trona mine projectis analyzed with focus on the multi-lateral drilling process, such as well structure design and optimization, suspended sidetrack drilling, drill bit and BHA design and optimization, drilling fluid design, etc.

Abstract:The Beypazari Trona Mine in Turkey has the characteristics of varying buried depth and thickness and proneness to pinch out, and water kicks occurs frequently while drilling at the edge of the mining area, which leads to different casing setting positions in the vertical wells of the same solution mining well set, or the mining trona layer where casing has been set is unstable and needs to be changed. In order to solve these problems, the section-milling technology was introduced and applied to expose the previously isolated trona bed and form a new mining passage. A total of 14 wells were drilled by applying this technology on the project, and all achieved satisfied results. In the paper, the section-milling process is illustrated by taking the drilling of the H066 well set as an example. Comparing with drilling a new well, it reduces greatly the construction period and saves drilling costs. Field use demonstrated that the technology is beneficial in changing the mining layer, treatment of downhole incidents, and provides many advantages such as less drilling time, less drilling cost, extension of the service life of old wells, increasing of resource recovery; therefore it has a broad application prospect.

Abstract:In Kazan Trona Mine in Turkey, the method of solution mining with intersected well set has been adopted with around 100 intersected well sets drilled successfully, which has brought about remarkable social and economic benefits. In order to improve the utilization rate of the trona resources, based on the current situation and geological conditions, three alternative schemes for simultaneous mining of multiple trona layers with an intersected well set for the Kazan Phase IV drilling project are put forward in the paper. With the overall plan determined, the well layout principle for simultaneous mining of multiple layers is put forward, and the three schemes are briefly expounded and the index of them are compared. The 3rd alternative scheme (1 horizontal well +2 vertical wells) is selected since it provides the advantages of less drilling work, shorter construction period and lower investment cost. Description is made in detail of vertical well drilling, horizontal well drilling and solution mining operation with some related technical problems and suggestions were put forward. The simultaneous mining scheme can provide some guidance and reference for simultaneous mining of multi-layer trona mines and increase of resource recovery.

Abstract:Kazan Trona Mine in Turky is characterized by complicated geological settings, high content of insolubles in the primary mining layer and high dip angles of ore beds, which leads to frequently blockage problems during commercial solution mining. This paper takes Unit P078 horizontal intersected well as an example to describe the drilling techniques and leaching history, and analyze the causes of blockage. By following the principle of “from easy to difficult, minimizing risks and controlling the cost”, various attempts were taken to deal with the problem, such as single well circulation, pressurizing the channel by cementation truck, and circulating drilling mud to clean the borehole, and finally, it was decided that sidetracking was applied to drill a lateral to connect both targets, and it was proved to be successful with minimum costs and low risks. Some suggestions related to construction, design, repair and solution mining operations were put forward. The experience can provide some guidance and reference for solving blockage problems in the similar scenario.

Abstract:The horizontal intersected well set project at Kazan Trona Mine and Beypazari Trona Mine in Turkey boasts of the largest scale in the world by far, with large amount of drilling work and huge technical difficulty. This paper summarizes the common downhole drilling incidents and complex situations that frequently occurred during drilling, such as sticking, drilling fluid loss, and breaking off drilling tools, analyzes the cause of the incidents in combination with the actual cases, compares the different results achieved by different treatment methods, and finally proposes some safe and effective measures for incident prevention and treatment. The experience accumulated on the project could be used as a reference in similar drilling projects for prevention and treatment of downhole drilling incidents.

Abstract:The requirement on the quality control in the technical specifications is very strict for drilling of the solution mining intersected well sets at Kazan Trona Mine. The vertical wells were easily deviated, with low core recovery and poor cement bonding due to the complex geology, the high dip angle of the formation, and presence of several aquifers; meanwhile, for the horizontal well, it was very difficult to control the trajectory. After a thorough analysis of data obtained from previously drilled wells and a study of related issues and optimization of solutions, several measurements were put forward and applied. The results showed that all the drilling problems were effectively solved, the drilling process was improved, and the construction period was reduced. The experience acquired from the project could be used as reference for the similar works.

Abstract:HSE managemnt is an essential requirement for the modern enterprise to go abroad and carry out large scale international project, and plays an increasingly important role in the management of the project. During the running of the intersected solution mining well set construction project of Kazan natural trona mine in Turkey, we took experience of related domestic and abroad companies as reference, combined the properties of the project, and founded a HSE management organization. Firstly the employee safety training and upgrade of drilling equipment were performed for the purpose of meeting the requirements by local laws and regulations. Then the HSE management system was established by introuducing job safety analysis tool. Onsite supervision was fatal for an effective HSE management, which provides an safeguard for the running of the project.