Saudi develops technology to boost gas recovery

Saudi Arabia has developed a new technique to maximize recovery from its gas fields as it is pressing ahead with an ambitious programme to increase production and meet a rapid rise in domestic gas demand.

The government-owned Saudi Aramco, the world’s largest oil producing company, said it had successfully tested the new technique, known as hydrajetting, on one field and would apply it to more reservoirs.

Aramco, which has been pumping oil for more than seven decades, said stimulating gas reservoirs in the Gulf Kingdom, particularly in horizontal producers, has presented a considerable challenge to the Company as wellbore accessibility is difficult in wells drilled in deeper formations, with relatively low permeability and high-pressure and temperature.

As a result, conventional stimulation methods have not been as successful as expected when applied in single and dual-lateral completions, it said.

“Alternative techniques, based on hydrajetting technology, have been recently applied in a number of underperforming horizontal gas producers with excellent results,” Aramco said in its quarterly bulletin, Journal of Technology.

The report noted that the majority of Saudi Aramco’s gas producers, targeting reservoirs in deep and tight formations, are being drilled horizontally to optimize field development, achieve maximum reservoir contact and reduce overall cost.

Stimulation treatments are required on some of them because their productivity is frequently impaired by either drilling damage or poor reservoir quality.

“The conventional stimulation methods applied early in the field development history, which included bull-heading acid at high-pressure and rate conditions, and performing coiled tubing (CT) acid washes, did not improve well productivity at the expected level…this was not entirely surprising given the difficulty of placing treatment fluids - in targeted zones in need of stimulation along lengthy open hole horizontal completions - in the presence of thief zones, washouts and highly hetero - geneous reservoir conditions,” the report said.

“The problems - associated with initiating and extending hydraulic fracturing treatments in vertical wells, drilled in some of the tightest formations and perforated with conventional methodologies - led to the search for non-conventional methods, capable of overcoming the high fracture initiation pressure experienced in these wells. An innovative hydrajetting tool was developed and field tested for the first time in a vertical gas producer.”

It said the same technique, in combination with other innovative approaches, was later successfully used to perform acid stimulation treatments in a number of
underperforming horizontal open hole producers with “excellent results.”

Explaining the hydrajetting method, Aramco said it applies a high-velocity stream of fluid, carrying small abrasive particles, to create slots into the hydrocarbon bearing reservoir. Conventional methodologies had achieved only limited success in the same wells, the Company added.

“After the first successful application of hydrajetting in a vertical well drilled in a sandstone reservoir, it was recognized by the technical team that the methodology and tools could be enhanced and used to perform pinpoint acid stimulation treatments, in both vertical and horizontal wells,” it said.

“Massive hydraulic fracturing acid stimulation treatments have been successfully used to achieve multifold rate increases in vertical gas producers; drilled in carbonate reservoirs since the beginning of the gas development program. Hydrajetting technology has allowed Saudi Aramco to successfully overcome some of the challenges in effectively stimulating complex producers.”

The report said the successful results achieved in the different applications, have provided the incentive to continue to enhance the capabilities of the available tools for use in combination with others.

“The application of hydrajetting technology in multiple settings has helped Saudi Aramco to effectively stimulate vertical and horizontal gas producers….the post-stimulation results from the use of this technology have yielded a significant improvement over results achieved in offset wells (with similar reservoir characteristics), treated using conventional stimulation methods,” the report said.

“The ability to effectively stimulate targeted zones along horizontal sections in open hole completions has been significantly enhanced, through the implementation of hydrajetting technology…..future  planned applications of hydrajetting tools, in combination with other technologies, will continue to enhance our ability to effectively stimulate complex and difficult to access multilateral completions.”

Saudi Arabia, the world’s oil superpower, has been locked in a drive to develop its gas sector to face a steady and rapid growth in local consumption.

The country has the world’s fourth largest gas reserves after those in Russia, Iran and Qatar but most of them are associated with oil, making their separation a costly process. Increasing gas output also entails higher crude production, which will affect Riyadh’s commitment to OPEC’s output quotas.

Nearly a decade after they were awarded massive concession areas in the Empty Quarter (Rub Al-Khali desert), Shell and several other companies have failed to find major quantities of gas, prompting France’s Total oil giant to withdraw from the largest consortium in 2008.

The consortium--The South Rub Al-Khali Company (SRAK)-- is now equally owned by Saudi Aramco and Shell Saudi Ventures Lt.

SRAK’s concession covers 210,000 square kilometres, almost the size of Britain. Total had owned 30 per cent of the venture, while the Dutch Shell Group controlled 40 per cent and the rest was held by state-owned Saudi Aramco.

Besides SRAK, other joint ventures are hunting for hydrocarbons in the Empty Quarter after winning separate bids within the so-called “Gas Initiative” that was launched by King Abdullah bin Abdul Aziz nearly 10 years ago.

Saudi Arabia hopes new gas discoveries would boost its existing reserves to meet local consumption and build export projects.

The Kingdom, which controls nearly a quarter of the world’s recoverable oil deposits, has around seven trillion of proven natural gas resources.
 

Follow Emirates 24|7 on Google News.