Advanced Light Weight Thixotropic Lost Circulation Cement Solution for Vugular and Natural Fractured Limestone Formations: UAE Offshore Case History

2021 ◽  
Author(s):  
Mahamat Habib Abdelkerim Doutoum ◽  
Romulo Francisco Bermudez Alvarado ◽  
Ahmed Rashed Alaleeli ◽  
Thein Zaw Phyoe ◽  
Jose Salazar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Gel Strength ◽  
Strength Development ◽  
Lost Circulation ◽  
High Compressive Strength ◽  
Wide Range ◽  
Naturally Fractured ◽  
Compressive Strength Development ◽  
Surface Section ◽  
Fractured Limestone

Abstract Lost circulation while drilling across vugular or naturally fractured limestone formations is a costly challenge and has financial impacts including nonproductive time and remedial operational expenses. Many fields in the UAE are encountering notorious lost circulation complications, which are difficult to control with conventional lost circulation solutions while drilling surface sections. Novel lightweight thixotropic cement has proven beneficial to take control of severe losses in these vugular and naturally fractured limestone formations. The main challenge while drilling across the surface section in UAE offshore field is the heavy or total loss of returns. Drilling performance is affected due to poor hole cleaning, a risk of stuck pipe, surface fluid handling problems, and well control risks. Conventional extended cement slurries have been widely used to cure losses while drilling but with limited success. A new lost circulation solution combines lightweight (10.5- lbm/galUS) high solids fraction cement (trimodal system) and a thixotropic agent, which develop fast gels with high compressive strength. Thus, it enables plugging of large voids and fractures to deliver the wellbore integrity required to continue drilling with enhanced performance and efficiency. Intensive laboratory qualification tests focusing on static gel strength and compressive strength development was performed to tailor the new solution. The results were promising with more than 100 lbf/100 ft2 of static gel strength in 10 minutes and compressive strength development of 1,000 psi within 24 hours at low surface temperature. In addition, a transition time (TT) on-off-on test demonstrated more rapid gel strength development when the shear is reduced and regained fluidity with reapplication of shear. In one of the wells, heavy losses were encountered while drilling across surface section. The lightweight thixotropic solution was pumped for the first time worldwide and it was shown that the innovative lost circulation solution was effective in significantly reducing the losses and enabled the operator to continue drilling to section TD. This case study demonstrates that this advanced system is effective in curing losses and reducing nonproductive time. The unique properties of faster rapid gel strength and high compressive strength make this solution effective for treating a wide range of lost circulation events while drilling. Furthermore, the advanced lightweight thixotropic cement lost circulation solution exhibits strong performance in curing heavy losses and establishing well integrity with reliability.

Engineered High-Performance Lightweight Thixotropic Lost Circulation Solution for Vugular and Natural Fractured Formations UAE Case History

2021 ◽  
Author(s):  
Thein Zaw Phyoe ◽  
Jose Salazar ◽  
Eduardo Herrera Albuja ◽  
Saurabh Kapoor ◽  
Mohd Waheed Orfali ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Drilling Fluid ◽  
Oil And Gas Industry ◽  
Gel Strength ◽  
Strength Development ◽  
Lost Circulation ◽  
Main Challenge ◽  
Compressive Strength Development ◽  
Surface Section

Abstract Lost circulation while drilling across vugular or naturally fractured formations is a difficult challenge which will come with high cost for the oil and gas industry. When lost circulation encounter, the drilling company will result in nonproductive time and remedial operational expenses. Most of the fields in UAE are encountering lost circulation problems while drilling across surface sections, which are difficult to control with conventional lost circulation solutions. Newly engineered high-performance lightweight thixotropic proves beneficial to control losses in vugular and natural fractured formations. The main challenge while drilling the surface section in one UAE field is the total loss of returns and flowing formation. This leads to the inability to continue drilling due logistics to continue producing drilling fluid and to keep the well under control and risk of stuck pipe due to poor cuttings removal. Conventional low-density cement slurries have been widely used to cure losses while drilling, but with low effectiveness. A new lost circulation solution that combines lightweight (10.5–lbm/galUS) high-performance cement and a thixotropic agent produce an engineered high-performance lightweight thixotropic lost circulation solution with fast gel strength and improved compressive strength, enabling the plugging of large voids and fractures to recovery wellbore integrity required to continue drilling. Extensive laboratory qualification tests were performed for static gel strength development to confirm the plugging efficiency and compressive strength development. The results were promising with more than 110 lbf/100 ft2 of static gel strength in 10 minutes and compressive strength development of 1,000 psi within 24 hours at low surface temperature. In addition, a transition time (TT) with on-off-on test demonstrated more faster gel strength development was developed when the reduction of the shear rate and regained pumpable with reapplication of shear. In one of the wells, total losses were encountered while drilling across surface section. The lightweight high-performance thixotropic solution was pumped for the first time worldwide, proved that the innovative lost circulation solution was effective in curing the losses, and enabled the operator to continue drilling the section to TD. This case study demonstrates that the engineered system is effective in curing losses and reducing nonproductive time. The unique properties of more faster gel strength and enhanced compressive strength make this system more effective for treating a different types of lost circulation scenarios during drilling (Jadhav and Patil, 2018). New high-performance lightweight thixotropic cement lost circulation solution exhibits strong performance in curing total losses and establishing well integrity with reliability.

Performance Evaluation of Agarwood Distillation Waste as Retarder for High Strength Oilwell Cement

2014 ◽  
Vol 548-549 ◽  
pp. 101-105
Author(s):  
A. Sauki ◽  
A. Azizi ◽  
Nur Hashimah Alias ◽  
Nurul Aimi Ghazali ◽  
T.A.T. Mohd ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Main Idea ◽  
High Strength ◽  
Strength Development ◽  
Fluid Loss ◽  
Oil Well ◽  
Testing Procedures ◽  
Wide Range ◽  
Compressive Strength Development ◽  
Cement Strength

Cement strength must be carefully maintained so that the cement is able to sustain formation stresses without failing. Such a mechanical failure in a cement sheath can cause a loss of annular isolation. A synthetic polymer cement retarder has been designed to provide extended pumping times for cement slurries, while having minimal effect on compressive strength development. However, it is difficult to select a retarder that can suit a wide range of field conditions. Fluid loss control can also be affected by the addition of a retarder, especially at high temperatures. Addition of retarder sometimes may increase the viscosity and pumping pressure of the slurry and may result in fracturing of the hydrocarbon bearing zone and costly job failure. The main idea for this study is to determine whether Agarwood waste from distillation process (AGW) can be used as a retarder in oil well cement with excellent compressive strength development. The compressive strength developments were evaluated at different curing time and particle sizes of AGW which are 90 μm, 150μm and 250μm. The performance of AGW slurries were compared with commercial retarder slurry. Apart from that, chemical analysis on AGW was conducted by using X-ray Fluorescent (XRF) to determine the presence of cementations component in this material. All cement testing procedures should follow API recommended specification 10B standard. From the results obtained, the performance of 250 μm of AGW is better than commercial retarder by 10% increment in the development of cement strength.

A la recherche d'un béton de 150 MPa

1983 ◽  
Vol 10 (4) ◽  
pp. 600-613 ◽  
Author(s):  
Claude Bedard ◽  
Pierre-Claude Aitcin
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Research Effort ◽  
High Strength ◽  
Strength Development ◽  
Manufactured Sand ◽  
Strength Concrete ◽  
High Compressive Strength ◽  
Grain Size Distributions ◽  
Compressive Strength Development

It is possible to make in 1983 a field concrete in the Montreal area having a 28-day compressive strength of 120 MPa, using locally available materials.To obtain such a high compressive-strength concrete, it has been necessary to study the overall performances of 8 different cements, 3 types of sand, 16 types of aggregates, 3 types of superplasticizers, 9 grain-size distributions of the coarse aggregate, and 5 different ways of batching. An ultra high strength concrete is not obtained by chance, but through a long research effort planned in a laboratory as well as in the field.Such a concrete is feasible using: (1) high cement dosage of type 10, 20, or 30, according to the desired rate of compressive strength development; (2) a cubical coarse aggregate having a high compressive strength and an elastic modulus as near as possible as that of the mortar; (3) a manufactured sand having a high fineness modulus made from the same rock as the coarse aggregate; (4) a very high dosage of superplasticizer; and (5) 5 to 8% of condensed silica fume. The limited efficiency of the present industrial mixers (tilt mixers) for the very special mixes of this study is actually the main limitation for reaching a strength of 150 MPa. Keywords: high compressive strength concrete, superplasticizer, condensed silica fumes, manufactured sand, grain-sizes, aggregates, retarder, ready-mix concrete, precast plants.

scholarly journals The potential use of pumice in mine backfill

2020 ◽  
Vol 1 ◽  
Author(s):  
Mohammed A. Hefni
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Mining Industry ◽  
Strength Development ◽  
Natural Pozzolan ◽  
Mine Backfill ◽  
Natural Pozzolans ◽  
Cemented Backfill ◽  
Compressive Strength Development ◽  
Potential Use

Abstract The use of natural pozzolans in concrete applications is gaining more attention because of the associated environmental, economic, and technical benefits. In this study, reference cemented mine backfill samples were prepared using Portland cement, and experimental samples were prepared by partially replacing Portland cement with 10 or 20 wt.% fly ash as a byproduct (artificial) pozzolan or pumice as a natural pozzolan. Samples were cured for 7, 14, and 28 days to investigate uniaxial compressive strength development. Backfill samples containing 10 wt.% pumice had almost a similar compressive strength as reference samples. There is strong potential for pumice to be used in cemented backfill to minimize costs, improve backfill properties, and promote the sustainability of the mining industry.

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