Coiled tubing drilling for unconventional reservoirs: the importance of cuttings transport in directional drilling

2014 ◽  
Vol 54 (1) ◽  
pp. 329
Author(s):  
Mohammadreza Kamyab ◽  
Nelson Chin ◽  
Vamegh Rasouli ◽  
Soren Soe ◽  
Swapan Mandal

Coiled tubing (CT) technology has long been used in the oil and gas industry for workover and stimulation applications; however, the application of this technology for drilling operations has also been used more recently. Faster tripping, less operational time, continuous and safer operation, and the requirement for fewer crew members are some of the advantages that make CT a good technique for drilling specially deviated wells, in particular, in unconventional reservoirs for the purpose of improved recovery. Cuttings transport in deviated and horizontal wells is one of the challenges in directional drilling as it is influenced by different parameters including fluid velocity, density and rheological properties, as well as hole deviation angle, annulus geometry and particle sizes. To understand the transportation of the cuttings in the annulus space, therefore, it is useful to perform physical simulations. In this study the effect of wellbore angle and fluid rheological properties were investigated physically using a flow loop that has been developed recently for this purpose. The minimum transportation velocity was measured at different angles and an analysis was performed to study the fluid carrying capacity and hole cleaning efficiency. The results indicated how the change in wellbore angle could change the cuttings transport efficiency.

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Subhash N. Shah ◽  
Yunxu Zhou

This study experimentally investigates the drag reduction characteristics of the most commonly used polymer fluids in coiled tubing applications. The flow loop employed consists of 12.7mm straight and coiled tubing sections. The curvature ratio (a∕R, where a and R are the radii of the tubing and the reel drum, respectively) investigated is from 0.01 to 0.076, which covers the typical curvature ratio range encountered in the oil and gas industry applications. Fluids tested include xanthan gum, guar gum, and hydroxypropyl guar at various polymer concentrations. It is found that the drag reduction in coiled tubing is significantly lower than that in straight tubing, probably due to the effect of secondary flow in curved geometry. The onset of drag reduction is also found to be delayed as the curvature ratio was increased. A correlation for the maximum drag reduction (MDR) asymptote in coiled tubing is developed. When the curvature ratio is set to zero, the new correlation reduces to the well-known Virk’s MDR asymptote for dilute polymer solutions in straight pipes. A new drag reduction envelope is proposed for the analysis of drag reduction behavior of polymeric fluids in coiled tubing. Application of the new drag reduction envelope is also discussed.


Author(s):  
Subhash N. Shah ◽  
Yunxu Zhou

This study experimentally investigates the drag reduction characteristics of the most commonly used polymer fluids in coiled tubing applications. The flow loop employed consists of 1/2-in. straight and coiled tubing sections. The curvature ratio (a/R where a and R are the radii of the tubing and the reel drum respectively) investigated is from 0.01 to 0.076 which covers the typical curvature ratio range encountered in the oil and gas industry applications. Fluids tested include xanthan gum, guar gum, and HPG (hydroxypropyl guar) at various polymer concentrations. It is found that the drag reduction in coiled tubing is significantly lower than that in straight tubing, probably due to the effect of secondary flow in curved geometry. The onset of drag reduction is also found to be delayed as the curvature ratio was increased. A correlation for the maximum drag reduction (MDR) asymptote in coiled tubing is developed. When the curvature ratio is set to zero, the new correlation reduces to the famous Virk's MDR asymptote for dilute polymer solutions in straight pipes. A new drag reduction envelope is also proposed for the analysis of drag reduction behavior of polymeric fluids in coiled tubing. Application of the new drag reduction envelope is also discussed.


2021 ◽  
Author(s):  
Emmanuel Ayodele ◽  
David Ekuma ◽  
Ikechukwu Okafor ◽  
Innocent Nweze

Abstract Drilling fluid are complex fluids consisting of several additives. These additives are added to enhance and control the rheological properties (such as viscosity, gel strength and yield point) of the mud. These properties are controlled for effective drilling of a well. This research work is focused on determining the rheological behavior of drilling mud using industry-based polymer and Irvingia Gabonensis (ogbono) as viscosifiers. Water based muds were formulated from the aforementioned locally sourced viscosifier and that of the conventional used viscosifier (Carboxylmetyl cellulose, CMC). Laboratory tests were carried out on the different muds formulated and their rheological properties (such as yield stress, shear stress, plastic viscosity and shear rate) are evaluated. The concentration of the viscosifiers were varied. The expected outcome of the research work aims at lowering the total drilling cost by reducing the importation of foreign polymer which promotes the development of local content in the oil and gas industry. The research compares the rheology of mud samples and the effect of varying the concentration (2g, 4g, 6g, 8g, and 10g) of both CMC and Ogbono and determining the changes in their rheological properties. The total volume of each mud sample is equivalent to 350ml which represent one barrel (42gal) in the lab. From the result, at concentration of 2g, the ogbono mud has a better rheology than the CMC mud, but at a concentration above 2g, CMC mud shows a better rheology than ogbono mud, that is, as the concentration of CMC is increased, the rheological properties of the mud increased while as the concentration of ogbono is increased the rheological properties decreased. The viscosity of the drilling fluid produced from the ogbono were lower than that of CMC, it could be used together with another local product such as cassava starch, offor or to further improve the rheology and then be a substitute to the conventional viscosifiers.


2021 ◽  
Author(s):  
Risal Rahman ◽  
Reyhan Hidayat ◽  
Pratika Siamsyah Kurniawati ◽  
Rantoe Marindha ◽  
Gerardus Putra Pancawisna ◽  
...  

Abstract Nowadays oil and gas industry are encouraging the independents and majors to take a fresh look at the technology and concepts required to develop marginal shallow water fields using a minimal platform approach. Innovation on well intervention means (lighter, smaller and less footprint) that fit for Offshore Minimalist Platform (OMP) is needed, including optimizing time and cost during well intervention activities in OMP. To achieve the objectives, well intervention innovation and technology are the main focuses. Intervention activities commonly done on campaign basis with several units (slickline, wireline, coiled tubing, testing) shall be integrated in a safe manner. The approach of integration shall signify these points:Identifying potential jobs in OMP to be done by well intervention methodsIdentifying necessary well intervention means and methods to support the jobs (combo unit, micro coil, hazardous zone redefinition, remote operation)Creating project planning and schedulingPerforming site visit and risk assessmentImplementation and operational executionEvaluation of overall project execution result The following results were obtained after the integration performed:No major safety issues during operationExemplary method and risk assessment for well intervention activities which can be applied for next campaignsTrials on well intervention new units and method (combo unit, micro coil, hazardous zone redefinition, remote operation), were safely performed with some optimization100% success ratio60% on supply boat arrangement35% efficiency in N2 consumption for CT operation45% efficiency in diesel consumption20% - 40% efficiency in Rig Up Time28% less in Job Cost compared to conventional unit These innovations are proven as reliable method to answer OMP challenges with main advantages on footprint and cost optimization. Through this paper, we would like to share lucrative well intervention breakthrough and innovation in OMP with measurable milestones.


2021 ◽  
Author(s):  
Alexander Katashov ◽  
Igor Novikov ◽  
Evgeny Malyavko ◽  
Nadir Husein

Abstract Over the past few years, the oil and gas industry has faced a situation of high fluctuations in hydrocarbon prices on the world market. In addition, the trend for the depletion of traditional hydrocarbon reservoirs and the search for new effective solutions for the management and control of field development using horizontal and multilateral wells is still relevant. The most common method for horizontal wells testing is production logging tools (PLT) on coiled tubing (CT) or downhole tractor, which is associated with HSE risks and high cost, especially on offshore platforms, which limits the widespread use of this technology. The solution without such risks is the method of marker well monitoring, which allows obtaining information about the profile and composition of the inflow in a dynamic mode in horizontal wells without well intervention. There are several types of tracer (marker) carriers and today we will consider an approach to placing marker monitoring systems as part of a completion for three-phase oil, water and gas monitoring.


2015 ◽  
Vol 55 (1) ◽  
pp. 329
Author(s):  
Ghazal Avijegon ◽  
Joel Sarout

Borehole instability is a recurring issue encountered during drilling operations in the oil and gas, and mining industries. In exploration drilling using coiled tubing technology, boreholes are slim and the annular space is usually tight. Similar situations are also encountered around the drill-collar section in standard drilling where the annular space can be tight; therefore, the drilling fluid has a high flow velocity and a turbulent flow regime is dominant. The flow conditions are the governing conditions for borehole erosion, which can lead to borehole instability. Erosion of the borehole introduces more cuttings into the annulus space, which is detrimental to the efficiency of cuttings transport and brings contamination to samples being retrieved at the surface for geochemistry and mineral analyses. In this peer-reviewed paper a new laboratory set-up aimed at estimating borehole erosion in pre-drilled rock samples is reported. A flow loop unit is used, which allows the injection of high flow-rates of any type of fluid composed of chemical additives and simulated cuttings. Early results of an exploratory study are reported in terms of changes in the internal borehole diameter (ID) of the sample before and after the erosion experiment. These were recorded using X-ray CT scanning. This change in ID acts as a measure of the formation’s erodibility, from which shear stress is estimated.


2011 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Piroozian ◽  
Issham Ismail

Lencongan dari laluan tegak menyebabkan rincisan gerudi berkumpul pada bahagian bawah lubang telaga sehingga terbentuknya lapisan rincisan. Akibatnya, berlaku beberapa permasalahan operasi ketika berlangsungnya penggerudian. Daya seret dan kilas yang melampau, kesukaran yang dialami ketika penyorongan rentetan selongsong ke dalam lubang telaga, kesukaran untuk memperoleh operasi penyimenan yang baik, dan lekatan mekanikal paip gerudi adalah antara beberapa contoh lazim yang berkaitan dengan permasalahan terbabit. Sehubungan itu, pemahaman yang baik tentang parameter utama operasi yang mempengaruhi pembersihan lubang telaga adalah penting. Artikel ini mengetengahkan keputusan daripada kajian makmal yang telah dilaksanakan untuk menilai keberkesanan tiga jenis bendalir gerudi dalam menyingkir rincisan gerudi. Kajian makmal melibatkan penggunaan gelung legap aliran sepanjang 17 kaki dengan diameter 2 inci sebagai bahagian ujian. Bagi setiap uji kaji, prestasi pengangkutan rincisan (CTP - Cuttings Transport Performance) ditentukan menerusi pengukuran berat. Keputusan uji kaji dianalisis untuk memperoleh kesan menyeluruh ketiga-tiga parameter operasi, iaitu kelikatan bendalir gerudi, halaju bendalir, dan kecondongan lubang telaga. Kajian terkini membuktikan bahawa penggunaan bendalir gerudi berkelikatan tinggi berupaya meningkatkan CTP jika regim aliran adalah gelora. Walau bagaimanapun, peningkatan kelikatan dalam regim aliran peralihan atau laminar masing-masing mengurangkan CTP secara beransur atau mendadak. Kajian juga menunjukkan bahawa peningkatan sudut kecondongan dari 60° ke 90° memberikan kesan yang positif terhadap CTP. Parameter operasi yang memberikan kesan yang ketara dalam kajian ini ialah halaju aliran, dengan peningkatan kecil yang dialami oleh halaju aliran berjaya memberikan kesan positif yang nyata dalam pembersihan lubang telaga. Kata kunci: Kecekapan penyingkiran rincisan; prestasi pengangkutan rincisan; rincisan gerudi; bendalir gerudi; pembersihan lubang telaga Deviation from vertical path makes drill cuttings to accumulate on the lower side of the wellbore that induces the formation of cuttings bed. Subsequently, relative problems occur while drilling. Excessive torque and drag, difficulties in running casing in hole and accomplishing good cementing jobs and mechanical pipe sticking are few of the classical examples of such problems. Therefore, a comprehensive understanding of influential parameters on hole cleaning seems to be essential. This paper presents results of an experimental study that was carried out to evaluate cuttings removal efficiency of three types of drilling fluid. Experiments were conducted using a 17 feet long opaque flow loop of 2 inch diameter as test section. For each test, the amount of cuttings transport performance (CTP) was determined from weight measurements. Three operating parameters were considered, namely drilling fluid viscosity, fluid velocity, and hole inclination. It showed that the use of high-viscosity drilling fluid improved CTP if the flow regime was turbulent. However, increasing viscosity when flow regime was transient or laminar flow lessened CTP gradually or sharply respectively. It was also revealed that an incremental increase in hole inclination from 60° to 90° has a positive effect on CTP. The most influential parameter in this study was fluid velocity in which a small raise of fluid velocity resulted in a substantial positive effect on hole cleaning. Key words: Cuttings removal efficiency; cuttings transport performance; drill cuttings; drilling fluid; hole cleaning


Author(s):  
Robson Santana Nóbrega Alves ◽  
Byron Gonçalves de Souza Filho

Horizontal Directional Drilling, as known as HDD, is a method of construction that requires few trenches or no continuous trenches, used for making crossings under rivers, roads and existing structures. In the oil and gas industry, it is most commonly used in offshore and onshore well drilling activities to better explore the reservoir from a single well. It is also very much used when laying pipelines, where no other feasible option is possible. This technology was widely applied in the Urucu-Manaus natural-gas pipeline construction by Petrobras, and Transpetro has been responsible for the operation and maintenance of this pipeline since November 2009, flowing Natural Gas from the heart of the Amazon forest mainly to the growing market of thermoelectric plants. Due to its extension in the forest, the crossing of numerous wide navigable rivers and other natural obstacles was unavoidable, and no other construction methods were more suitable than the HDD technology. This work shows the application of this method in the 1777m long crossing of the Solimões River during the construction of this 662km Natural Gas pipeline. It also shows the challenges faced due to the logistical adversities in the rainforest, as well as the operations by Transpetro.


SPE Journal ◽  
2017 ◽  
Vol 22 (04) ◽  
pp. 1189-1200 ◽  
Author(s):  
Xianzhi Song ◽  
Zhengming Xu ◽  
Mengshu Wang ◽  
Gensheng Li ◽  
S. N. Shah ◽  
...  

Summary Microhole-drilling technology is a high-efficiency and low-cost technology that has developed rapidly in recent years. However, during microhole-horizontal-well drilling, cuttings are easy to deposit at the bottom of the wellbore because of gravity and nonrotation of drillpipe. Inadequate drill-cuttings removal can cause costly problems such as excessive drag, and even mechanical pipe sticking. Therefore, many laboratory studies as well as field observations have been directed toward addressing the cuttings-transport problem. In the present study, a full-scale horizontal-cuttings-transport flow loop was set up and a total of 136 experiments were conducted. By analyzing the cuttings volumetric concentration and the dimensionless height of the cuttings bed, the effects of flow rate (0.00058–0.00078 m3/s), cuttings diameter (0.0003–0.005 m), rate of penetration (ROP) (0.00211–0.00636 m/s), eccentricity (0–0.8), and wellbore diameter (0.04–0.08 m) on wellbore-cleaning efficiency were obtained. It was found that cuttings-transport efficiency increased first and then decreased as cuttings diameter increased. Flow rate was the main parameter. Higher flow rate, lower ROP, lower eccentricity, and smaller drillpipe/wellbore-diameter ratio all led to higher wellbore-cleaning efficiency in microhole horizontal wells. In addition, a model for estimating the cuttings volumetric concentration and the cuttings-bed height was proposed by dimensional analysis dependent on the thorough understanding of the effects of various variables. The predictions were good when they were compared with the experimental data obtained. Major factors influencing cuttings transport in the field during microhole drilling and conventional rotary drilling were compared, and the reasons for their differences were discussed. The limitations of the proposed model in this study were also discussed. These results could provide a factual basis for improving microhole-drilling hydraulics.


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