Coiled tubing (CT) fill cleanouts have been in existence for over four decades and today account for approximately 30% of the services performed. Both CT and conventional jointed pipe offer a forward or reverse circulation mode to remove solids; however, using conventional water-based fluids, a sand cleanout method may apply excess hydrostatic pressure to the formation, resulting in some lost circulation to a sub-hydrostatic reservoir. Nitrogen (N 2 ) can be used to reduce hydrostatics, but this requires a very precise job design and execution. Moreover, N 2 use can have adverse logistical and economic implications -large amounts of N 2 may be needed, especially in larger diameter wellbores and in horizontal wells.Several cleanout methods have been utilized in the past, employing a variety of different approaches. CT historically has incorporated limited circulation rates, exotic/costly fluids and reversing circulation to remove solids. The use of CT to remove sand from wellbores was one of its earliest applications and continues to be an important service today. This paper will discuss cost-effective solutions in Saudi Arabia, highlighting field cases and job optimization. The selection of the most appropriate sand cleanout method has to be based on both logistical and technical issues. This paper shows how to select the most cost-effective fills cleanout method for these wells. A few field cases are discussed to demonstrate the proper operational procedure, challenges and lessons learned. The combination of how to utilize the sophisticated solids transport software, downhole switchable nozzle, and proper operational procedure with the frequent evaluation of downhole conditions on site is essential to insure the fills cleanout is executed 100% successfully.

This paper presents a study of horizontal well completions equipped with inflow control devices (ICDs) in a large, unconsolidated sandstone reservoir in Saudi Arabia. The focus is the improved production performance gained through a completion using ICDs with variable nozzle settings across the openhole section vs. that from a cemented, perforated liner completion and uniform nozzle setting ICD completion performance. Discussion includes an overview of ICD and intelligent completions and their components, and the advantages and limitations of both uniform/variable types of ICDs completion design methods. Results from two wells in Saudi Arabia show that the major advantages of completions using ICDs with variable nozzle settings are the operator's ability to make adjustments at the wellsite; to balance the inflow from areas of differing permeability; to reduce the pressure drop across the completion; and to better controls water production compared with uniform nozzle setting ICD completion. Inflow Control Device (ICD) technology has been developed to overcome horizontal well production/injection challenges. ICD completion with packers segregates openhole (OH) horizontal section into compartments to balance inflow/outflow along the well and control undesirable water/gas production. There are various types of ICDs such as tube, helical, orifice and nozzle ICDs. The advantages of orifice/nozzle ICDs (Fig. 1) are their viscosity independence and the nozzle installation at the wellsite according to the attained while drilling properties/openhole logs that might change ICD completion design optimization. The optimum ICD completion is one which balances influx from heterogeneous reservoirs and control water/gas production and simultaneously without creating a huge pressure drop across the completion.

Locating downhole casing leaks in producer and injector wells is not a complex undertaking when using rig-operated straddle packers with pressure testing. However, this established technique has limited effectiveness because it does not necessarily address the overall comprehensive integrity of the entire completion, which might include additional intervals of serious corrosion leading to leaks in the near future.We examined the results of low-frequency electromagnetic (EM) remote frequency eddy current (RFEC) wireline logs from over 80 wells in one mature Middle Eastern offshore field, profiling the severity of measured metal loss (ML) from concentric casings against proven rig-discovered leaks and rigless measurements of subsurface ML. Casing leaks that otherwise would have been detected only by conventional zonal pressure testing from a workover rig can now be located and forecasted with a high degree of probability when using this evaluation tool.The importance of maintaining oilfield casing integrity for safety, environmental, and flow assurance objectives, combined with the high costs of drilling new wells, creates a necessity for this integrated well integrity appraisal approach. Application of this EM logging technology to identify intervals of external ML has great significance in being able to anticipate casing intervals with high likelihood of failure due to invasive corrosion.

Fiber optic enabled coiled tubing (FOECT) has been commonly used in qualitatively evaluating reservoir matrix chemical treatment in real time during the past couple of years. During this period, attempts of transforming qualitative evaluations to quantitative ones were made. The quantitative evaluation is based on two simultaneous criterions. The first one is a downhole pressure diagnostic plot (pressure transient analysis) created instantinuously using real-time acquired data by the downhole gauges. The second is an estimate of the zonal coverage based on the resulting temperature profile plot before, during and after a pumping treatment. Pressure transient analysis gives the skin as a direct output, while the cooling down/warming up DTS profiles identifies where the treatment fluids went in the formation, hence identifying the damaged zones. It is strongly recommended to combine well testing analysis techniques with zone coverage evaluation in highly deviated and horizontal completed wells in both clastic and non-clastic rocks. Basically, deriving the skin from the injectivity test (pretreatment) and the skin from the post flush (post-treatment) provides an evaluation matrix treatment effectiveness. A comparison between formation damage "skin" before and after the treatment was performed on the spot, revealing positive results of nearly uniform distribution of treatment fluids, and skin value reduction across the 3400 ft horizontal section. Following the innovative procedures executed in well-A, different techniques were proposed, providing time and cost savings; raising the operational excellence expectations levels higher than expected for an offshore environment. The application of FOECT technology helped to minimize uncertainties during treatmentevaluation, and enhanced treatment distribution and placement. In addition to establishing more accurate and reliable Nodal Analysis and production forecast models.

In one Saudi Aramco offshore oil field, the formation fluids are being produced from different platforms and transported to one onshore gas-oil separation plant (GOSP) where the produced water is removed from the hydrocarbon stream. The produced water is injected back to highly permeable formations through disposal wells with no interruption. In this way, the water disposal system is an integral part of the hydrocarbon recovery system. A failure of one of the disposal wells could adversely affect oil production. Saudi Aramco petroleum engineers are placing more and more attention on water disposal wells as a higher volume of produced water from the increasing hydrocarbon production rates has to be disposed of continuously every day. The primary objective of surveillance on the disposal wells is to keep an extra disposal capacity for continuous oil production from the field and to precisely monitor the decline rate of the capacity of each disposal well. Areal sweep efficiency and pressure maintenance are not the surveillance scope for water disposal wells in our case. Few technical papers have been published that discuss the problems a water disposal system may have in a matured field and address issues such as surveillance of well performance and water quality, formation damage mechanisms, treatment and so forth. In this paper, the existing water disposal system in a matured offshore oilfield is briefly described and discussed with the surveillance of well performance and the quality disposal water, potential problems, and the evolution of the surveillance philosophy. The reasons why most disposal wells experienced severe injection decline are analyzed and discussed in detail. Historic treatments were summarized with actual outputs demonstrating" ineffective" treatments for the issues discussed. After several trial tests, one customized chemical treatment recipe was developed to effectively tackle the issues and actual well data is included showing the effectiveness of those treatments. A new surveillance strategy for better monitoring of well performance and the quality of "waste" fluid is also discussed in this paper. It can be concluded from our work that formation damage exists extensively in wastewater injection wells and that it greatly influences the performance of disposal wells. Any treatment for restoring the injection capacity of water disposal wells impaired by low quality water is expensive. Any successful treatment is rooted into the detailed analysis of the problems. Implementation of a proper surveillance program and appropriate processing of the injection fluid is also vitally important for wastewater management.