The long term zonal isolation is an important factor to be considered while designing cement slurries for deep High Pressure, High Temperature (HPHT) gas well. Conventional heavy weight cement systems which have been used in the past have often had to sacrifice the set cement mechanical properties such as compressive strength, permeability, and porosity, to provide a slurry design which is stable, mixable and pumpable. Changes in downhole conditions in terms of temperature and pressure can induce sufficient stresses to destroy the integrity of the cement sheath which will cause long term gas migration and sustained annular pressure. Hence, the set cement mechanical properties have to be carefully designed in order to withstand the downhole stresses especially the ones generated during the well testing and fracturing treatments. This paper will discuss the selection and the Novel Flexible and Expanding cement system and details one well case history of nine wells which is part of the upstream agreement with Saudi.

Many "poor" gas prospects-particularly ultralow-permeability and porosity unconventional rocks such as tight sand-become economic success when hydraulic fractures are created in the pay zone. The fractures allow a single well bore to contact many thousands of square feet reservoirs. Using swellable packer technology has mechanically simplified fracture job. Using multiple packers ensures the entire zone is treated; or in other words, knowing where the fracture fluid goes once it exits the casing, and how each set of fractures is isolated from another is a key in a successful hydraulic fracture design. Lukoil Saudi Arabia started an exploration campaign in the Rub’Al-Khali Empty Quarter in 2006 targeting Non Associated Gas and nine wildcat exploration wells have been drilled and evaluated. It was found during the early stages of the exploration that the gas accumulations in LUKOIL Saudi Arabia exploration Area (Block-A), were typically trapped in tight to ultra-tight reservoirs (see Fig. 1). These gas discoveries in the Empty Quarter have occurred in High Pressure and High Temperature (HPHT) horizons at depths between 12,000 and 20,000 ft, where the stress and temperature are extremely high in addition to micro-Darcy levels of reservoir permeability. This has made the exploration activity more challenging. Figure 1 Location of Project Area in Rub Al-Khali Desert

In this paper, attempts have been made to describe the experiences of 1.5 months of Managed Pressure Drilling (MPD) operations conducted in hard rock Formation in Rub Al-Khali, Eastern province of Saudi Arabia.The implementation of this technology arose from the lessons learnt from previously drilled 2 exploratory wells that penetrated the tight gas sandstone Formations of Sarah and Qasim at a depth exceeding 17,000 ft, where the temperature and stress are extremely high at 350 o F and 1.0 psi/ft respectively. As a result of these conditions, it is necessary in all cases to perform hydraulic fracturing to define fluid characteristics and evaluate production potential.The extreme low porosity range of 2-10 % coupled with low permeability range of 0.01 -0.26 mD and high fracture gradient interval of 0.9 -1.0 psi/ft are the main challenges on these wells. Moreover, other challenges faced include drilling with high overbalance mud weight across the reservoir and high abbresivity of the formation rocks resulting in difficulty identifying potential gas bearing sands and slow drilling rate respectively.As a part of the referenced exploratory activity in the 3 rd quarter of 2008, LUKSAR was challenged to drill across the target reservoir with minimum formation damaged, balance mud weight and swift reaction in identifying suitable coring interval. Hence, in response to these challenges, an extensive study and well design/engineering were carried out in order to accommodate the utilization of Managed Pressure Drilling (MPD) across Sarah-Qasim sandstone Formation on wells LUK-08 and LUK-09. This paper summarizes the well operation and in particular lessons learned during the first field application of Managed Pressure Drilling (MPD) in LUKSAR Exploration Campaign that resulted in significant improvement in well deliverability compared to previously drilled wells in Sarah-Qasim structure.

The article deals with the issues related to the modelling of unsteady fluid flow in short and long pipelines, including various equipment: pumping stations (equipped with cen-trifugal or piston pumps), valves of different operating principle, pressure stabilizers, etc. Pres-sure stabilizers (especially in short pipelines) are able to protect the pipeline from sudden pres-sure surges. This is important not only in terms of the strength of the pipeline system, but also in short pipeline circuits for a uniform flow of liquid fuel supply. As a mathematical tool for numerical solution of differential equations of quasi-hyperbolic type, the method of character-istics is applied, which allows to consider the problems that develop over time. The program is written in C++ with graphical interpretation in Maple.

The long term zonal isolation is an important factor to be considered while designing cement slurries for deep High Pressure, High Temperature (HPHT) gas well. Conventional heavy weight cement systems which have been used in the past have often had to sacrifice the set cement mechanical properties such as compressive strength, permeability, and porosity, to provide a slurry design which is stable, mixable and pumpable. Changes in downhole conditions in terms of temperature and pressure can induce sufficient stresses to destroy the integrity of the cement sheath which will cause long term gas migration and sustained annular pressure. Hence, the set cement mechanical properties have to be carefully designed in order to withstand the downhole stresses especially the ones generated during the well testing and fracturing treatments. This paper will discuss the selection and the Novel Flexible and Expanding cement system and details one well case history of nine wells which is part of the upstream agreement with Saudi.