Casing While Drilling Successfully Implemented for the First Time in High Risk Area of the Bahrain Field

One known risk of the Awali field is hole collapsing in the surface section due to the presence of floating bloulders and cavities in areas of the field; resulting in wells being abandoned as conventional drilling was not enough to solve this issue. In 2019, Schlumberger and Tatweer Petroleum combined forces to improve production of Ostracod/Magwa shallow reservoirs by drilling wells in new areas of the field which included drilling in locations with offset wells that were abandoned due to hole collapse issues in the first 500’ interval. Drilling campaign started in june 2019 and drilled succesfully two wells, but two others were abandonned due to hole collapse issues. These abandonned wells were in very promising production areas as per the reservoir model and due to the shallowenest of the reservoir, it was not possible to move the surface location. Therefore, the issues in the surface section needed to be solved in order to maximize profits in the country. Following a rigerous study for determining which is the optimal solution for drilling the surface section in this area of the field, Casing While Drilling (CwD) technology was selected and implemented in August 2019 in well A-1530D, next to the previous abandoned wells. CwD operation was performed with excellent results by drilling from 101ft to 520ft with no issues. CwD successfully isolated the higly problematic zones in the surface section and more importantly, allowed to reach areas of the reservoir that had high potential for production.

MSE Based Drilling Optimizer Project for Large National Drilling Contractor

A large GCC National Drilling Contractor is planning to trial a new MSE (Mechanical Specific Energy) Drilling advisory system based in artificial intelligence (AI) on a conventional drilling rig. This system works by means of calculating the optimal auto driller input parameters to achieve higher drilling efficiency. The objective of the MSE based Drilling Optimization system is to drive drilling efficiency by way of advising surface drilling parameters (WOB and RPM). The system will be tuned to advise/automatically modify WOB and RPM for each specific run, section, or well. The parameters can be adjusted in one of the two following ways: Advisory Mode: A recommended WOB and RPM value is sent to the driller, who then manually applies the setpoint change Control Mode: The setpoints are sent to the automatic driller for instant and automated application The system shall enable reduction of NPT and rig days to drill wells by increasing efficiency with consequent cost reduction efficiency by utilizing advanced elements of Artificial Intelligence (AI).

Low Cost Plug and Abandonment with Hybrid Hydraulic Pulling Unit

Plug and Abandonment (P&A) operations with conventional Hydraulic Workover Unit (WHU) have an enormous benefit and impact on low-cost P&A campaign in Malaysia compare with using conventional drilling rig. Subsequently, this Hybrid Hydraulic Pulling Unit (HHPU) was the first successful deployed and safely delivered for P&A campaign together with conductor removal in offshore West Malaysia. This paper presents case study that showcase the capability of HHPU for low-cost permanent P&A campaign by eliminate requirement for additional bringing rigging-up and rigging-down of casing jack unit for conductor removal operation. The unit manage to cut and pull-out the existing completion strings, setting cement plugs, cut and pull-out multiple strings of casing along with retrieving the 24″ conductors delivering the most advantageous outcome for P&A campaign safely, efficiently and cost effectively. It was invented from 340K HWU with improvise features that capable of pull-out existing completion string and removal of the conductor with size up to 36″. This paper demonstrates a unique combination of techniques and equipment of a successfully low-cost P&A operation with excellent client satisfaction with no incident and accident were recorded. The end results may contradict traditional P&A methods, but the case history can be used for future reference or potential replication in South East Asia region.

Study on the Mechanical Extended-Reach Limit Prediction Model of Horizontal Drilling with Dual-Channel Drillpipes

Extended-reach horizontal wells are critical for the development of unconventional reservoirs. Dual-channel drill pipe drilling has a great advantage in improving the horizontal section length, while the research on its mechanical extended-reach limit prediction model is insufficient. In this paper, the torque and drag model is built considering the additional axial force of the sliding piston on the dual-channel drillpipe. Based on the torque and drag model, the mechanical extended-reach limit model for dual-channel drilling is established. A case study including a comparison to the conventional drilling method and sensitivity analysis is conducted. The result shows that under the same conditions, the mechanical extended-reach limit of the dual-channel drilling method is 10,592.2 m, while it is 9030.6 m of the conventional drilling method. The dual-channel drilling method achieves a further mechanical extended-reach limit than the conventional drilling method. To improve the mechanical extended-reach limit of dual-channel drilling, a higher back pressure on the sliding piston, a deeper measured depth of the sliding piston, a higher density of the passive drilling fluid, a smaller outer diameter of the outer pipe, a lower weight on bit and rate of penetration should be adopted. The work in this paper completes the extended-reach limit theory of dual-channel drilling, providing a guide for better use in unconventional reservoir development.

An Experimental Investigation of Drilling Performance Improvement Using Reaming While Drilling

This work investigates the drilling performance by reaming while drilling (RWD) using a dual-body bit and compared it with conventional drilling by a standard drilling bit. The dual-body bit consisted of a 2.45-in pilot bit located at a short distance ahead of a 2.47*3.97-in reamer. Conducting a series of drilling experiments at a simulation drilling rig with full monitoring sensors, we further studied the drilling performance as a function of the distance between the pilot bit and the reamer which affect mud diffusion and the resultant change in pore pressure and stress. A method was devised to eliminate the drill-string vibration and its effect on the drilling performance and the energy consumed. The mechanical specific energy (MSE) calculated for each case was considered as a drilling performance indicator. Using two laboratory experiments as well as analytical thermo-poro-elastic calculations of the Mechanical Specific Energy (MSE), the MSE changes were monitored and recorded. Comparison of this drilling performance indicator was used in both the RWD and the conventional drilling assembly to analyze the effect of RWD. Based on the results, with increasing the distance between the pilot bit and reamer, there is an increase in improvement of drilling performance in terms of MSE reduction. The best drilling performance indicator (MSE reduction of 84%) was observed with the distance between the pilot bit and the reamer of 43.3 cm. This is considered a novel finding in reaming while drilling.

The Effect of Biopolymer Chitosan on the Rheology and Stability of Na-Bentonite Drilling Mud

The utilization of greens resources is a grand challenge for this century. A lot of efforts are paid to substitute toxic ingredients of the conventional drilling mud system with nontoxic natural materials. In this paper, the effect of the natural polymer chitosan on the rheology and stability of sodium-bentonite drilling mud was investigated in the polymer concentration range of 0.1–3.0 wt.%. Both the shear and time dependent rheological properties of pure chitosan, pure bentonite and bentonite–chitosan dispersions were studied. Moreover, zeta potential measurements were used to evaluate the stability of bentonite-chitosan suspension. Adding chitosan improved the natural properties of drilling mud, namely: yield stress, shear thinning, and thixotropy. The viscosity of bentonite suspension increased significantly upon the addition of chitosan in the concentration range of 0.5 to 3.0 wt.% forming network structure, which can be attributed to the interactions of hydrogen bonding between -OH clusters on the bentonite surface with the NH group in the chitosan structure. On the other hand, dispersed chitosan–bentonite suspension was observed at low chitosan concentration (less than 0.5 wt.%). Increasing both bentonite and chitosan concentrations led to the flocculation of the bentonite suspension, forming a continuous gel structure that was characterized by noteworthy yield stress. The desired drilling mud rheological behavior can be obtained with less bentonite by adding chitosan polymer and the undesirable effects of high solid clay concentration can be avoided.

Analytical Study of Early Kick Detection and Well Control Considerations for Casing while Drilling Technology

Recently, casing while drilling (CwD) technology has been employed to reduce drilling time and expenses. These intelligent drilling technique improved wellbore stability, fracture gradient, and formation damage while reducing exposure time but when a well control issue arises, the differences in wellbore geometries and related volumes compared to regular conventional drilling procedures necessitate a distinct strategy. In this paper, the essential well control parameters were provided for casing while drilling operations, presents simplified method that has been developed to evaluate the maximum kick tolerance (KT) for both conventional and casing while drilling techniques using a mathematical derivation, the narrow annular clearance, in contrast to drilling with a conventional drill string would impair kick detection and handling operations. Furthermore, the large disparity in kick tolerances should be carefully evaluated in order to avoid lost circulation/kick cycles as well as examine and evaluate technical approaches to early kick detection (EKD) studying how they relate to safety, efficiency, and reliability in a variety of common casing while drilling operations. According to preliminary findings, by utilizing casing while drilling technology and compared to identical well was drilled conventionally using drill pipe, the annulus pressure loss (APL) is average 3 times of the conventional drilling technique. Furthermore, kick tolerance is reduced by 50% and maximum allowable well shut-in time reduced by 65% necessitating early kick detection.

Production and Performance Evaluation of Biodetergents as an Alternative to Conventional Drilling Detergent

Drilling detergents are among the chemical compounds that are increasingly being used in many varieties of drilling fluids. They are aqueous blend of surface-active agents that reduces the surface tension of water-based drilling fluids, reduces the sticking tendency of water-sensitive shale cuttings and aid cuttings removal; leading to cleaner hole, faster penetration rates and lower drilling pressure. Due to the increase in environmental issues associated with the disposal of drilling detergent presently used, drilling companies are exploring options of using environmentally friendly, degradable and renewable drilling detergents. In this study, biodetergents were produced from non-edible seed oils (Ricinus communis oil and Azadirachta Indica oil). The biodetergents and a commercial drilling detergent used in the Niger Delta field were analysed for a number of standard properties required for good drilling detergents. Drilling muds formulated with these detergents were also analysed for a number of standard mud properties. Physicochemical properties analyses showed that biodetergents met the required specification of good drilling detergents. The physicochemical properties of the biodetergents were also comparable to that of commercial drilling detergent. BOD values obtained showed that the biodetergents could easily be broken or biodegraded than the commercial drilling detergent. Toxicity test on Penaeus Monodon showed that biodetergents are more environmentally friendly than the commercial drilling detergent. Drilling mud properties analyses further showed that synthesized biodetergents can be used as an alternative to conventional drilling detergent.

Evaluation of the Performance of Conventional Water-Based Mud Characteristics by Applying Zinc Oxide and Silica Dioxide Nanoparticle Materials for a Selected Well in the Kurdistan/Iraq Oil Field

Nanomaterials have gained a wide interest in the oil and gas industry due to their immense applicability. Nanomaterials are being used to formulate a new generation of drilling mud known as Nanomud or Smart mud, where it has the ability to improve mud properties and eliminate borehole problems. Using nanoparticles as an additive agent in conventional drilling mud can lead to a more efficient drilling process in troublesome formations. In this study, several conventional water-based muds from a selected well drilled in the Kurdistan/Iraq oil field have been prepared. Then, nanodrilling muds were formulated by dispersing SiO2 and ZnO nanoparticles in concentrations ranging from 0.25 to 1 wt.% to conventional water-based mud (WBM). This study aims to evaluate and compare the performance of conventional water-based muds after adding SiO2 and ZnO nanoparticles. This evaluation was performed by carrying out a series of laboratory experiments to determine the rheological and mud filtrate properties. The results demonstrated that nanomuds improved the rheological behaviors and provided better filtration control compared to conventional drilling muds. However, there was little or no impact of the nanomaterials on the mud density for all mud systems.