No abstract

Economic exploitation of low-permeability or tight sandstone and carbonates can be an elusive endeavor. New technologies and approaches are needed to make these more challenging reservoirs economically attractive. The completion technique discussed in this paper has been successfully employed in previously non-economic gas reservoirs in North America. The main focus of this completion technique is enhanced reservoir connectivity with the wellbore. Other completion techniques have previously been used to successfully improve reservoir contact and enhance production. These techniques are similar in their focus on improved reservoir connectivity by compartmentalizing the wellbore into multiple sections. They do, however, have their limitations in low-permeability or tight formations. The novel completion technique presented in this paper involves horizontal drilling through a reservoir combined with compartmentalizing the wellbore into multiple sections. Each wellbore section is then individually fractured in order to effectively propagate fractures through the reservoir, thus greatly increasing productivity in each zone. Up to twenty-four zones can be set up, allowing operators to customize their stimulation program in long-reach horizontals in heterogeneous and low-permeability reservoirs. Detailed knowledge of the existing natural fracture network, the current-day stress field, and geomechanical considerations are key inputs to a valid reservoir model, reducing the risk of establishing undesired flow paths with the aquifer, for example. This paper will illustrate how this new technology has enabled operators to benefit from significant economic improvements through operational efficiencies achieved during the drilling and completion phase based on reduced rig time and faster, more cost-efficient completions. Water shutoff options available with this new type of approach will also be discussed. Multistage fracturing leads to higher initial production, improved reservoir drainage, better control on fracture propagation, and controlled production from fractures in low-permeability sandstone and carbonate reservoirs as well as in gas-shales, which will be illustrated with case histories from these operating environments

TX 75083-3836, U.S.A., fax +1-972-952-9435. AbstractOpenhole horizontal completions in consolidated formations have been commonplace for a number of years. This type of completion has been very successful due to the relative simplicity of the completion design and ability to segment the horizontal production interval by using openhole hydrostatic-set packers. Using inflow control devices (ICDs) in this completion design allows a uniform inflow across the entire horizontal wellbore, which mitigates early water or gas coning into the wellbore.A newly designed ICD has been developed and field-trialed successfully that eliminates the need for an inner string during installation, allowing circulation through the liner while running in hole as well as hydraulic setting of the openhole packers before pulling out of hole with the workstring. This also provides an improved well control condition. A temporary valve system has been incorporated into the ICD design that provides pressure integrity in the liner until after the upper completion has been installed. Once the upper completion is in place, the valves are triggered hydraulically with applied pressure in the production tubing and opened once the differential pressure is removed, allowing the ICD to be reconfigured into the production mode. Once the valves have been opened, the ICD performs normally for the operational life of the well.This completion technology also provides the added benefit of isolating the upper wellbore from the reservoir until after the upper completion is installed. This potentially prevents unwanted and costly fluid losses into the formation before the well is put on production. This paper will describe the new ICD design technology developed for the application and review initial case history well installations in Saudi Arabia.

The BP Operated Foinaven, Schiehallion and Loyal fields, located West ofShetland (WoS) in the UKCS, are a highly challenging environment to work in.The three deepwater fields are drilled and completed utilising 4th generationsemisubmersible rigs and the harsh marine environment can severely impactoperations. Although standalone screen completions have been used successfully in themajority of the wells, premature sanding problems have been experienced, potentially jeopardizing project economics due to prohibitively high cost ofremediation. To improve this situation, alternative means of sand controlcompletions have therefore been sought. There are now four Open Hole Gavel Pack(OHGP) completions in the fields, all of which are performing well with highproductivities and no sand production. In this paper, we present a case history on the application of thecirculating water pack in the Foinaven field. The P11 sidetrack is the thirdgravel pack completion in this deepwater environment, and the first to becompleted with a water pack. The subject well is the longest OHGP in BP's NorthSea portfolio with a 3,345 ft open hole, penetrating through two sand bodiesand multiple shale and mudstone packages. The well was designed with a long horizontal open hole section tocost-effectively access multiple sand bodies and maximise productivity whileminimising drawdown across the sandface. Baker Oil Tools BetaBreaker technologywas utilised for the completion to maintain the treatment pressure below thereservoir fracture gradient during the gravel pack. The well was completed witha +110% packing efficiency, has an early time mechanical skin of +2 based onpressure buildup testing and was delivered safely 5 days ahead of target atP(10) production expectations. Introduction The Foinaven P11 sidetrack (204/24a-A16z) was planned to replace theoriginal A04z production bore which had watered out and suffered from excessivelevels of sand production. The original P11 well (A04z) was completed withnon-compliantly expanded 5–1/2" expandable sand screens. The sidetrack wasdesigned with a long horizontal open hole section to cost-effectively accessmultiple sand bodies and maximise productivity while minimising drawdown acrossthe sandface. It was planned to access the reserves left behind in theabandoned motherbore as well as accessing new reserves to the East of theoriginal well location.

Openhole horizontal completions in consolidated formations have been commonplace for a number of years. This type of completion has been very successful due to the relative simplicity of the completion design and ability to segment the horizontal production interval by using openhole hydrostatic-set packers. Using inflow control devices (ICDs) in this completion design allows a uniform inflow across the entire horizontal wellbore, which mitigates early water or gas coning into the wellbore. A newly designed ICD has been developed and field-trialed successfully that mitigates the need for an inner string during installation, allowing circulation through the liner while running in the hole as well as hydraulic setting of the openhole packers before pulling out of the hole with the workstring. This also provides an improved well control condition. A temporary valve system has been incorporated into the ICD design that provides pressure integrity in the liner until after the upper completion has been installed. Once the upper completion is in place, the valves are triggered hydraulically with applied pressure in the production tubing and opened once the differential pressure is removed, allowing the ICD to be reconfigured into the production mode. Once the valves have been opened the ICD performs normally for the operational life of the well. This completion technology also provides the added benefit of isolating the upper wellbore from the reservoir until after the upper completion is installed. This potentially prevents unwanted and costly fluid losses into the formation before the well is put on production. This paper will describe the new ICD design technology developed for the application and review initial case history well installations in Saudi Arabia.