Step Change in Delivering High Fracture Wells by Eliminating Expandable Liner

This paper discusses the journey of finding alternate solution for having to run the Expandable Liners operations in the Fahud field which is already one of the most operationally challenging fields to drill in Petroleum Development Oman (PDO), due to the presence of a gas cap in highly fractured and depleted limestone formations with total losses and the need for dynamic annulus fill to maintain primary well control. In Fahud field, there is a highly reactive shale formation within reservoir limestone formation. Due to high likelihood of total losses, this shale formation caused bore hole instability challenges while drilling. And with more depletion took place, the challenges became more frequently to occurred. In 2001, expandable tubular liner was introduced to address these bore hole instability challenges while drilling highly reactive shale formation under total losses in the 8-1/2″ section. The use of expandable technology was sustained over the years in delivering all wells drilled to traverse this reactive shale column. Previously before 2001, wells used to have fat well design by installations of extra casing to cover the formations and problematic zones. Also, Fahud field was not depleted as it is now, and the problematic shale zone used to drill by normal conventional way without any issue using inhibition frilling fluid. Petroleum Development Oman (PDO) identified expandable liner as a preferred alternative to ‘Fat’ well design. The ‘Fat’ well design would have a large hole size through potential loss zones, resulting in unmanageable volumes of water being required. Expandable liber was fast-tracked - various technical options were considered by PDO with expandable liner technology being identified as the best solution to address the problem of the shale column. However, the deployment of expandable tubular liner technology supported to drill & deliver wells but also has its associated challenges incurring additional time and cost with reasonable installation and low operations success rate due to number of operational steps required prior and after the expandable liner. Adding to that, all the challenges associated with each step. The installation of the expandable liner required eight operational steps with multiple trips to under-ream, install and expand, cement, caliper log and drill through the liner which increased the probability of something going wrong due to mainly the challenging well profile and multiple operations steps. The expandable liners technology was required when the target formation was below the reactive shale interval. The team carried out a study of previous deployments with the intention of identifying well planning and operational contributors to the installation difficulties and operations failures, with a view of eliminating the need for installing the expandable liner and drilling the well to the desired landing point at designed section total depth. Most of the unsuccessful installation rates were observed to be prevalent in wells with high angle applications. The team also observed that the length of the hole interval below the reactive shale column contributed to the number of unsuccessful installation and operational failure rates recorded. The team evaluated the impact of reducing well inclination on the ability to deliver the hole section without installing the expandable liner. Subsequently the team developed an optimization plan which involved keeping all build activities above and below the problematic interval and holding tangent at less than 45° inclination while drilling across the problematic shale. In conclusion, in 2020 the team delivered six wells (90% of wells crossing reactive shale formation delivered) using the above described approach and traversed the historically highly reactive shale formation without installing expandable liners. This resulted in a 20% reduction in total well construction time and 17% reduction in total well delivery cost per well. In addition to the time and cost saving, with the new approach, described in this paper, less water needed to be pumped for dynamic fill. This allowed bringing the wells quicker to production, thus reducing oil deferment.

LNMR Study on Microstructure Characteristics and Pore Size Distribution of High-Rank Coals with Different Bedding

In order to study the pore structure characteristics of high-rank coals with different bedding, NMR experiments were carried out for high-rank coals with different bedding angles (0°, 30°, 45°, 60°, and 90°). The results show that the distribution of T2 map of high-rank coal with different bedding is similar to some extent, showing a double peak or triple peak distribution, and the first peak accounts for more than 97% of the total, indicating that small holes are developed in high-rank coal with different bedding, while macropores are not developed. The influence of bedding angle on the fracture proportion is less than 0.3%. Compared with the fracture proportion, the effect of bedding angle on the proportion of microhole, medium hole, and large hole is greater and presents a certain rule. There are certain differences in T2 cutoff value (T2C) of high-rank coal with different bedding. The relationship between bedding angle and T2C conforms to exponential function, and the correlation degree R2 is 0.839. The research results provide a theoretical basis for gas extraction and utilization and prevention of gas disaster in coal mines in China.

Recent Trends in the Management of Aneurysmal Bone Cyst

Background Aneurysmal bone cysts (ABCs), were first described by Drs. Jaffe and Lichenstein in 1942 when they described pelvic and spine lesions that when exposing the lesion and opening in to its thin wall, the surgeon was immediately confronted by a large hole containing much fluid blood. Aim of the Work To describe the efficacy of new line treatment modalities of (Aneurysmal Bone Cysts) compared to conventional lines of management regarding the: • Long term outcomes and healing rate. • Recurrence rates. • Complications after therapy. Patients and Methods Criteria for considering studies for this review: • Types of the studies: published observational analytical studies (case-control_ case-series _ RCT or cohort studies) which studied the efficiency of new lines in the management of aneurysmal bone cyst. • Types of participants: participants were children and young age (below the age of 50 yrs) with a diagnosis of aneurysmal bone cyst. • Types of interventions: drugs like (Bisphosphonate or denosumab) were administered for a time determined by the case improvement, or minimally invasive techniques like (cryosurgery or curopsy) was done. Results Through the results of our study that compared between these recent modalities according to healing, recurrence, and complications rate; we are able to say that recent strategies have a high rate of healing ranges from 78.57% with bisphosphonate to 100% with doxycycline and cryotherapy. Conclusion There are recent evolving trends in the management of ABC other than the classic ways of management, they are less invasive, have less recurrence rate reaches to 0 % like with bisphosphonate, less complications rate as well reaches to 0 % like with doxycycline and bisphosphonate, high healing rate reaches to 100 % like with doxycycline and taking in consideration how to handle cases of ABC that classic way of management can’t handle like spinal ABC.

Experimental Study and Effective Width Method for Cold-Formed Steel Lipped Channel Stud Columns with Holes

The objective of this paper is to investigate the buckling behavior and to present the design method of the ultimate strength in the basic effective width method (EWM) for cold-formed steel (CFS) lipped channel stud columns with holes in the web. 28 column tests were conducted under axial compression on the CFS lipped channel stud columns with circular and rectangular holes in different dimensions of cross sections and holes. The tested stud columns included 4 members without holes, 12 members with circular holes, and 12 members with rectangular holes. The test results showed that the stud columns with holes were governed by local buckling or the interaction of local buckling and distortional buckling. Compared with the stud columns without holes, the small hole had a slight influence on the ultimate strength of the tested specimens, and the large hole had a great effect on the ultimate strength of the tested specimens. The load capacities of the specimens decreased with the increase of the dimension of holes. Then, the finite element analysis was carried out to simulate the tested stud columns. The finite element analysis results showed good agreement with the experimental results about buckling modes and ultimate strengths, which indicated that it is feasible to analyze this kind of stud columns with holes by using the finite element method (FEM). Finally, the proposed effective width method was used to predict the ultimate strengths of stud columns with holes based on the proposed buckling coefficient formulas of the plate with holes. The comparison between calculated results and test and finite element results indicated that the proposed EWM is feasible and accurate to predict the ultimate strength of the CFS lipped channel stud columns with holes in the web.

Conductor Sharing Drilling Technique

With the objective to drill two wells shared from one conductor with independent wellhead and completion, ADNOC Offshore drilling team pioneered for the first time in Umm Lulu field and ADNOC UAE the Conductor sharing drilling technique. Which is to drill two wells from one single conductor in wellhead tower. Well planning technique drilling 42" hole and run 36" conductor, then install lower male connector and run conductor Down Hole Guide (DHG) assembly to be a guide for both two wells. Land the DHG on the lower male connector. Install upper male connector, which is equipped with two well slots for drilling the two wells. Drilling 1st 16" hole and run 13 3/8" casing and cemented. Skid over second slot and drill second hole 16" and run and cement 13 3/8" casing and carry out top up cement job for both hole up to surface inside 36" conductor. Install casing head housing for each well. Then each well could be drilled as per normal procedures. Well executing process. Well challenges: Drilling large hole 42" hole with 42" bit and BHA. Run 36" conductor and conductor sharing DHG and keep aligned for accessibility of BHA and casing Nudge 16" hole for both two wells at centre-to-centre distance 8" safely without collision issue. Run two 13 3/8" casing strings in 36" conductor and cement same up to surface. Complete drilling well UL-056 from slot A, drilled 12 ¼" hole section to TH-I ABS, run 9 5/8" casing and perform cement job to surface, drilled 6" hole (linerless design) and land in TH II then continued drilling horizontal drain to TD, Run completion and deliver the well. Suspend the other well in slot B at 13 3/8" casing with securing the well with abandonment cap and as per ADNOC offshore policy.

How dopants limit the ultrahigh thermal conductivity of boron arsenide: a first principles study

The promise enabled by boron arsenide’s (BAs) high thermal conductivity (κ) in power electronics cannot be assessed without taking into account the reduction incurred when doping the material. Using first principles calculations, we determine the κ reduction induced by different group IV impurities in BAs as a function of concentration and charge state. We unveil a general trend, where neutral impurities scatter phonons more strongly than the charged ones. CB and GeAs impurities show by far the weakest phonon scattering and retain BAs κ values of over ~1000 W⋅K−1⋅m−1 even at high densities. Both Si and Ge achieve large hole concentrations while maintaining high κ. Furthermore, going beyond the doping compensation threshold associated to Fermi level pinning triggers observable changes in the thermal conductivity. This informs design considerations on the doping of BAs, and it also suggests a direct way to determine the onset of compensation doping in experimental samples.

The Efficiency of Large Hole Boring (MSP) Method in the Reduction of Blast-Induced Vibration

Drill and blast is the most cost-effective excavation method for underground construction, however, vibration and noise, induced by blasting, have been consistently reported as problems. Cut blasting has been widely employed to reduce the blast-induced problems during underground excavation. We propose that the large hole boring method using the state-of-the-art MSP (Multi-setting smart-investigation of the ground and pre-large hole boring) machine (“MSP method”) can efficiently improve vibration reduction. The MSP machine will be used to create 382 mm diameter empty holes at the tunnel cut area for this purpose. This study assessed the efficiency of the MSP method in reducing blast-induced vibration in five blasting patterns using a cylinder-cut, which is a traditional cut blasting method. The controlled blasting patterns using the MSP method demonstrated up to 72% reduction in blast-induced vibration, compared to the base case, Pattern B, where only cylinder-cut and smooth blasting method were applied. Therefore, the MSP method proves to be a promising alternative for blasting in sensitive urban areas where non-vibration excavation techniques were initially considered. Geological characteristics of 50 m beyond the excavation face can be acquired through the proposed real-time boring data monitoring system together with a borehole alignment tracking and ground exploration system. The obtained geological information will be a great help in preparing alternative designs, and scheduling of construction equipment and labour during the tunnel construction.

Polyphenylene sulfide-coated wrench composites by nanopinning effect

When using a wrench, the nut is easily damaged due to improper operation or impact. Although coating a polymer layer on the surface of the wrench can effectively solve the above problem, the layer is easy to be deboned due to the lack of adhesion between the polymer and the surface of the wrench. Herein, we implemented an anodizing treatment strategy on the surface of the wrench to obtain a porous oxide film. Interestingly, during the anodization process, micro-nanopores with a specific diameter can be obtained by adjusting the voltage, temperature, and electrolyte concentration. Furthermore, the ammonium fluoride/ethylene glycol electrolyte was used to etch the formed large hole to form the large hole sleeve small hole structure. In order to inject polyphenylene sulfide (PPS) molecules into multiscale holes to form a pinning effect, we also used nano molding technology to inject PPS into the metal surface. The results showed that the adhesion between PPS and the wrench was greatly improved compared with the commonly used dip coating method.