G. Robello Samuel

Field Validation of Transient Swab-Surge Response With Real-Time Downhole Pressure Data

This paper describes the field validation results of the transient swab-surge model with real-time downhole annular pressure data. The maximum pressures encountered during tripping or reciprocation are indispensible for making appropriate well-completion decisions. The prediction of swab and surge pressures is of critical importance in wells in which the pressure must be maintained within narrow limits of the pore and fracture pressures. It also plays a major role in running casing, particularly with narrow annular clearances. For these critical cases, a fully dynamic model is required to better estimate the maximum pressures encountered. This paper presents actual surge-and-swab field data collected with downhole-drilling-data measuring tools during tripping and circulating operations. These data were obtained from Alaska and North Sea wells with a range of hole diameters and different base-fluid muds. The data were compared and interpreted with steady-state calculations as well as a dynamic surge model, which includes the effects of fluid inertia and compressibility, wellbore elasticity, pipe axial elasticity, and temperature-dependent fluid properties. The sampling rate was specifically increased to 2 seconds and, in some cases, 1 second. This prevents downhole data attenuations and captures the full waveforms more accurately. Different operations were included in the downhole-drilling-data measuring tool runs to cover swabbing, surging, reciprocation, and simultaneous pumping operations during tripping. Model predictions for downhole pressure behavior were in excellent agreement with the measured real-time downhole pressure data.

Performance of Positive Displacement Motor (PDM) Operating On Air

Recent increase in application of horizontal wells and in particular underbalanced drilling, has triggered the necessity of a powerful pneumatic downhole motor. To enhance the technology and make the system effective, a mathematical model is required to identify the opportunities for the modification of power section design. It is well known that the performance of positive displacement motor operating on compressible fluid drops down drastically as compared to the operation under incompressible fluids. The frequent motor replacement during the operation incrementally increases the operating cost despite deriving potential benefits from underbalanced drilling.

Multistring Casing Design for Deepwater and Ultradeep HP/HT Wells: A New Approach

A new casing design approach includes effects of annular fluid expansion and pressure and provides a simple, practical way to examine casing designs during all phases of drilling and production.

Field Validation of Transient Swab/Surge Response with PWD Data

This paper describes the results of field validation of the transient swab, surge model with PWD (Pressure while drilling) data. The maximum pressures encountered during tripping-or reciprocation are indispensable for making appropriate well completion decisions. The prediction of swab and surge pressures are of critical importance in wells where the pressure must be maintained within narrow limits of pore and fracture pressures. It also plays a major role in running casing, particularly with narrow annular clearances. For these critical cases, a fully dynamic model is required to better estimate the maximum pressures encountered. This paper presents actual surge and swab field data during tripping and circulating operations collected using PWD tools. These data were obtained from Alaska and North Sea wells with a range of hole diameters and with different base fluid muds. The data were compared and interpreted with a dynamic surge model, which includes the effects of fluid inertia and compressibility, wellbore elasticity, axial elasticity of the pipe, and temperature dependent fluid properties. The sampling rate was specifically increased to two seconds and in some cases one second. This is done to prevent downhole data attenuations and to capture the full waveforms more accurately. Different operations were included in the PWD runs to cover swabbing, surging, reciprocation and simultaneous pumping operations during tripping. Model predictions of downhole pressure behaviour were in excellent agreement with the measured PWD data.

Optimal Design of Progressing Cavity Pumps(PCP)

The drive for energy independence has created a window of opportunity for innovations in oil recovery. New artificial lift methods like progressing cavity pumping have been successfully applied to downhole pumping applications. The multilobe pumps are also making inroads into the industry to be used under different operating conditions. Although the design has been mainly based on empirical standards and trial and error modifications, a more phenomenally optimum design of the pump is required to achieve a high efficiency standard. The optimal relationship between the pitch and the diameter of the housing is obtained to achieve a maximum flow rate for multilobe pumps.

Optimization of Drilling Parameters with the Performance of Multilobe Positive Displacement Motor (PDM)

Recent increase in application of coiled tubing for horizontal wells and in particular underbalanced drilling triggered the necessity of a powerful downhole motor. More often downhole motor stalling and motor replacement is a problem when using with coiled tubing drilling system. To enhance the technology and make the system effective, optimization of drilling parameters is essentially required. The frequent motor replacement during the operation incrementally increases the operating cost despite deriving potential benefits from coiled tubing drilling. The key to improved coiled tubing drilling system is a unified system approach that encompasses motor and bit. This paper presents an analytical study on the optimization of motor performance and drilling parameters. A new simple test called wear-off test is defined to establish an operating window. The practical usefulness of the theory. backed by the fundamental and optimal analysis for roller cone and diamond bits, is demonstrated with numerical examples.

A Practical Technique to Estimate the Formation Thickness of a Kicking Zone

Characterization of formation while drilling continues to be a challenge to the engineers. When a well kicks while drilling, evaluation of pore pressure and the corresponding kill mud density is of critical importance for the safety of the drilling crew and mechanical integrity of the wellbore. Besides the estimation of these parameters, it will be beneficial to estimate the thickness of the kicking formation prior to drilling. This helps to drill safely and carefully through the potentially active kicking formation. In this paper, it is shown how to calculate the thickness of the kicking zone with the limited information available at the time of an oil/gas kick. A method of data analysis (obtained on a kicking well) to estimate the formation thickness of the kicking zone is presented. Illustrative examples including actual field cases are described and analyzed.

Analysis of Energy Harvesting Positive Displacement Motor

Drilling operations in deep and ultradeep water are increasing around the world. The development of these substantial prospects provides many challenges and requires the integration of knowledge with prudent designs at different stages of the well development. Also, more wells are drilled in rotary steerable mode and other instrumented bottom-hole assemblies. All of these tools need power, which is stored in batteries. Because the downhole power supply is limited for these tools, an alternate mode of energy supply is needed so that these tools can remain downhole for long hours. This paper examines a new energy source extraction method using the hydraulic energy obtained from the circulated drilling fluid when downhole motors are used.