To maximize well productivity, Saudi Aramco embarked on a technology-driven strategy and began converting existing weak horizontal producers into maximum reservoir contact (MRC) wells. Many of these wells were completed with downhole smart systems to control flow from multiple laterals. Saudi Aramco also employed this strategy to convert dead vertical wells to single horizontal producers or power water injectors. A key driver in the success of this strategic approach has been the installation of solid expandable liners that have enabled zonal isolation and provided a conduit for any necessary smart-completion systems. Five wells to date have been successfully worked over with new 5 1/2 in. solid expandable liners that have been cemented when installed in the Shaybah, Ghawar and Abqaiq fields. Production data is projected to confirm the wells have achieved planned production gains. This paper will discuss the successful application of an alternative solid expandable technology, characterized by seamless expandable tubulars, robust and gas tight metal-to-metal seal connections, collapsible expansion cone, and lower-required expansion pressure; all of which provide technical improvements to more effectively meet application needs. This paper will also explain how an expandable system, when used as a production liner, offers additional benefits such as delivering extended-reach 5 1/2 in. laterals by using available technologies of geosteering, rotary steerable systems, and smart completions in the reservoir. Introduction Over the last several years Saudi Aramco has embarked on a technology driven workover strategy to maximize well productivity and total oil recovery by converting existing weak horizontal producers to MRC wells, many of which, if required by reservoir management, were installed with downhole smart systems to control flow from each lateral. This strategy has been also applied to convert dead vertical wells to single horizontal producers or power water injectors. A 5 1/2 in. solid expandable liner cemented in place is one of the key drivers that enable zonal isolation and provide a conduit for smart completion in the reservoir if required.
TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractTar-mat zones have been characterized at the base of oil columns in some of Saudi Arabia carbonate reservoirs. These zones form a barrier which physically isolates the producing zones and the injection water. As a result of this barrier, the reservoir pressure will decrease, which will require other means to produce these wells. This paper addresses two strategies to overcome potential problems resulted from tarmat zones.The first strategy was to drill a tunnel well. The tunnel well works as a conduit that connects the high pressure area to the low pressure area through the tar zone of the reservoir. Field data indicated that this well enhanced production rate of nearby wells and livened two dead wells.The second technique to address tar-mat present in another field is to use peripheral water injection. Water injectors with extended reach (ER) were completed horizontally at the bottom of the producing zones and just above the tar-mat zones. Challenges were faced in drilling these wells in a populated area in the northern area of Saudi Arabia and being stratified, tar-mat was encountered in open-hole sections of these wells. Tar content varies inconsistently around these injectors and more near wellbore and obviously in the tar layer. This limits the injection rate of these injectors initially to as low as 600 BWD at 2,400 psig.The low injectivity is attributed to the damage induced by the drilling mud (water-based mud) and the presence of tar and asphaltene in the injection zone. Acid stimulation treatments of these wells were needed to reach the target injection rate. A tailored acid treatment was designed to address these challengers. This treatment included pumping aromatic solvent, a regular acid, an emulsified acid and a viscoelastic surfactant-based acid for diversion.Because of environmental concerns, high H 2 S content, the spent acid was not lifted following the acid treatments. However, the injectivity index of horizontal injectors increased by several folds.The paper describes the efforts of a multi-disciplinary team to enhance the performance of these wells by using the latest technologies in drilling, logging, and well treatment.
A mature well in a carbonate reservoir in Saudi Arabia was no longer producing and was sidetracked in a workover operation to regain production. This paper describes the usage of swellable packers to isolate a detrimentally water producing fracture encountered during drilling of a 3–7/8" slim hole horizontal in a naturally fractured carbonate reservoir. No means of open hole/slim hole isolation were available prior to the introduction of swellable packers. The packers were successfully run and the well was brought into production at good rates and low water cut. Introduction Natural fracturing is believed to pervade most of the carbonate reservoir due to the brittle nature of these rocks. Today most production wells are drilled as 6–1/8" horizontals and completed with 4–1/2" inflow control devices and open hole packers to delay and manage water production. A number of workover wells are drilled with smaller bit sizes. Consequently, this requires slimmer completion equipment to complete the wells in an optimum manner. Well history Well A was drilled in 1999 as a 6–1/8" open hole high slanted (83°) producer and completed with 7" packer and 4–1/2" tubing. In 2005 the first workover operation was carried out to revive the well that was dead as a result of excessive water production. A window in the 7" liner was cut after decompleting the well and setting a whipstock. A 2,200ft 6–1/8" horizontal sidetrack was drilled in the formation and the well was completed with 7" packer and 4–1/2" tubing. The well was found dead after only one month of production. An acid job was subsequently carried out in an attempt to restart the productive life of the well; however it did not prove successful. Surface and downhole bailer samples were collected and lab tests suggested that an adjacent reservoir was dumping water into the formation. Another workover operation was planned and carried out in 2007. A balanced cement plug was set to abandon the existing lateral. A window in the 7" liner above the reservoir was cut, new 6–1/8" curve section to the top of the formation was drilled, an expandable liner run and set and a 5–1/2" horizontal hole was drilled. If needed, the well would be completed with inflow control devices and open hole packers. After the 5–1/2" shoe was milled out and a negative test was performed after displacing the well to water the well flowed water from the reservoir. A 4–1/2" scab liner was run to isolate the leak in the 5–1/2" liner from 6,598 to 6,720ft. A 3–7/8" open hole was drilled to TD at 8,800ft. A fracture was encountered at 7,586ft with total losses. The remainder of the lateral was drilled with water with no returns. The well was not logged since no caliper was available at that time for this hole size. Slim hole well design Saudi Aramco typically complete the 6–1/8" horizontal open holes in the carbonate reservoirs with inflow control devices to even out the inflow profile along the wellbore and to delay water break-through. Open hole packers are used to compartmentalize the open hole, to isolate fractures and hence manage water production in combination with the inflow control devices. No open hole packer technology was available or approved by Saudi Aramco for such slim holes prior to the introduction of swellable packers; i.e., there was no mechanical means of isolation of fractures or of compartmentalization. The potential consequence was excessive water production and loss of the lateral, resulting in a costly workover operation.
Preventing water or gas breakthrough and equalizing flow is one of the primary challenges of producing from horizontal slimhole wells. This paper will present a "first-of-its-kind" concept in which swellable packers were used to isolate a waterproducing fracture to prevent/delay water/gas breakthrough and equalize flow across a 3-7/8-in. horizontal open hole. The water-producing fracture was encountered during drilling of the slimhole horizontal in a naturally fractured carbonate reservoir. Prior to the introduction of swellable technology to the oilfield, satisfactory solutions for isolation in open hole slimhole wells had not been available. Although swellable technology was new to the area, after careful analysis of the situation, the operator and the service company decided to use four swellable packers to compartmentalize the hole.The completion configuration was successfully run, and the well was brought into production at good rates and with a low water cut.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.