TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWhen designing fracture treatments for high permeability formations, fracture conductivity is a primary factor in attaining maximization of completion economics. Optimum fracture design would dictate the knowledge of fracture orientation and the utilization of oriented perforation to optimally place the fracture. While in many unconsolidated formations, the contrast between horizontal stress is small or even insignificant; taking advantage of this situation often improves the efficiency and placement of a fracture.It is generally believed that existing spiral patterns used in more conventional slurry pack completions give better radial flow performance because of the uniform perforation distribution around the wellbore. However, when a hydraulic fracture is created, the majority of flow into the wellbore is delivered through the perforations that are communicated to the fracture. This is especially true when many of the unconsolidated formations suffer a high degree of damage around the wellbore. For this reason, it is important to focus fluids injected during the completion directly to the fracture and increase the number of perforations communicating with the fracture. This paper will discuss the justification and theoretical background for a newly proposed design that develops this concept. The paper also discusses the tools and procedures necessary to achieve the stated goals.A case history will be presented that will discuss the methods employed by an operating company in offshore Louisiana in perforating unconsolidated formations with the new system to obtain highly conductive gravel-pack fractures in deviated vertical wells. Significant to the success of the completions was the use of a high shot density perforating gun, oriented at 180-degree phasing. To facilitate the new approach, an innovative perforating gun system was also developed, and a wide perforation was designed to minimize friction.

The comparison of today's slickline capabilities with its early usage for routine remedial workovers and maintenance best illustrates the significant advances that have occurred within slickline technology. Today, for example, slickline can be used to I) set and retrieve slickline-retrievable safety valves or plugs, 2) open and close downhole circulating devices, 3)retrieve accurate depthhime data for correlating with memory production surveys for well diagnostics (problem identification) reservoir description, or flow analysis, 4) provide accurate correlation of tubing casing collars, and 5) pull and run multiple flow controls set packers and other downhole equipment without explosives; setting monobore tools; and other perform other well interventions that are dependent upon measurement accuracy. Less than a decade ago, slickline was only considered for mechanical well workovers. This paper will discuss the newly developed technology that allows slickline to economically provide alternatives to services traditionally reserved for other, more costly options. Case histories will be used to illustrate the enlarged scope of services and how the equipment combines to provide the innovative low cost service options that the industry has been seeking. Introduction Economic initiatives are usually the drivers of new technologies, and thus, reacting to the significant decline in the oilfield climate during the last decade, no era has been as momentous in providing stimuli for operational change. Unfortunately, operators who are seeking new methods usually look to new technologies as the potential problem solvers, and in so doing, overlook enhancements to the older, proven technologies that could provide the cost efficient alternatives they want. This has been the case with slickline. Until the resurgence of investigation into new strategies to meet the oilfield cost constraints of the last decade, slickline service was only considered for routine mechanical workovers. Who would have considered using slickline to set a packer in the early 90's. The capabilities that have changed the profile of slickline service from one of routine mechanical well work overs to a multi-faceted service technology are derived from the new slickline tools that can be used independently or combined to further enhance the scope of services. The equipment includes an electronic triggering device (ETD) that enables safe detonation of explosive devices, a battery-operated, electro-mechanical tool that sets wellbore devices on slickline and braided line without explosives, an electronic measurement system that automatically corrects measurement inaccuracies resulting from line stretch and environmental stress factors, a slickline collar locator (SLCL) that accurately verifies collar locations in a tubing string, and data job loggers or acquisition software systems that connect to the electronic measurement system to graphically record dynamic wireline information.

Traditionally, underbalance perforating has been the preferred perforation technique. Recently, however, a new extreme overbalance perforating (EOBP) that has the potential to improve the completion efficiency of a well without additional stimulation has been introduced. With this method a well with a fluid column is pressurized with nitrogen to above fracturing pressure of the formation before the gun is fired. Gas is then injected, with or without acidor proppants, to create short fractures that extend from the perforation tunnels. The presence of gas lowers the amount of liquid that contacts with the formation, facilitates the well's coming into production after perforation, and results in less formation damage. This new EOBP method creates highly conductive short fractures, the benefits of which outweigh any restriction that may be caused by perforating debris. The debris that exits the gun when it detonates will be pushed away from the wellbore during the pumping stage, and this will greatly diminish any adverse effects on productivity that overbalanced perforating could cause. This can be considered as a near-wellbore stimulation method that also improves the completion efficiency of a well by allowing perforating and stimulation to be accomplished in one operation. By performing two or more completion procedures during a single trip into the wellbore, service operators have been able to generate economical advantages. There are numerous ways in which EOBP may be performed. This paper will cover the design, planning techniques, and equipment that can be used to perform tubing-conveyed overbalance perforating. Examples and field cases will show scenarios in which wells with a variety of wellbore conditions such as open perforations and packerless and tubingless installations can be perforated in an extremely overbalanced condition. An analysis technique that can be applied to a short falloff test immediately following the perforation treatment as well as the standard well testing is also described in this paper. The method of analysis can be used to calculate skin damage, formation permeability, reservoir pressure, and if applicable, fracture parameters such as fracture half-length and conductivity. Several field cases are included to illustrate application of this method.

The detonation of explosives in the wellbore produces hazardous gas; however, these gases are not typically observed in high concentrations at the surface. Recently, during plug and abandonment (P&A) operations, carbon monoxide (CO) from perforation activities was observed in high concentrations. This paper examines these types of operations to determine root causes and mitigation methods. The anticipated amount of CO produced by detonation is calculated by both the empirical equation and reaction-equilibrium simulation methods for cyclotetramethylene tetranitramine (HMX), as well as by the simulation method for cyclotrimethylene trinitramine (RDX), hexanitrostilbene (HNS), and 2,6-bis,bis-(pikrylamino)-3,5-dinitropyridine (PYX). The life cycle of this gas from the time of generation through its potential release to the surface is discussed with the intent to reduce its quantity or concentration throughout. Mitigation methods include the incorporation of an oxidizer in the explosive reaction, chemical scavenging in the wellbore, and controlled venting or catalytic conversion at the surface. Significant quantities of CO are produced by perforating guns, with the proportion increasing for explosives of greater thermal stability until it is the single largest reaction product. During perforation, these gases are usually controlled by gas-handling equipment on the platform; however, the reduced availability of this equipment on the platform at the time of P&A operations is thought to be a contributing factor to the hazard. Another significant factor could be the use of a high circulation rate, which has the effect of increasing the concentration of the gas on the surface. Controlled venting, flaring, and catalytic conversion to carbon dioxide are feasible methods to help mitigate this hazard if conducted in accordance with regulations. This paper details the life cycle of CO gas generated from perforating activities and discusses how it can be hazardous during P&A operations. In addition, several methods are discussed that can help mitigate this hazard.

Thb paper wae prepared for preeentatlon at the SPE Middle East Oil Show held h Safvein, 11-14 Merch W95. This paper wee eeboted for presentation by m SPE Program Committee folbwlng review of information oorweined in en abstract submitted by the author(s). Contents of the pepsr, = Preeent@ have~*n rmw by the SOCbtY of Patrofem Engimsere end era svblaot to CWeotbn by the author(s). The material, 8s presented, does not necasawiiy reflect any position of the Sooiety of Patroleum Engineers, its offbare, or members. Papers presented at SPE meetings are subjaot to publicetiin review by Editorial Cwrtmhtees of the Sooiefy of Petroleum Enginwe. Permieebn to OQPYie restricted to en abstract of not more then XI(J wwds. Illustrefbns may not be oopled. The ebatraot shoutd oonteln oorwpiouous ecknowbdgment of where and by tiom the paper ie presented, Write Librerian, SPE, P.O. Sox S3StlW, Richardson, TX 750SNSSS, U.S.A., Telex, 1SS245 SPEUT.