新技術(shù)帶來(lái)井救援的春天-石油圈

新型井救援工具RWIS可以發(fā)揮真正的事半功倍效果！

編譯 | 驚蟄 TOM?

Trendsetter工程公司與Add能源公司結(jié)合了他們?cè)诰毓こ膛c設(shè)備設(shè)計(jì)方面的專業(yè)知識(shí)，開發(fā)出救援井注入工具（RWIS）。鑒于傳統(tǒng)的救援井方法在實(shí)際應(yīng)用中的低效率問題， RWIS系統(tǒng)可通過一口救援井，利用多艘泵船，每分鐘可泵入200桶的壓井泥漿，作業(yè)效率顯著提高。

在救援井與井噴井相交之前，RWIS被設(shè)計(jì)安裝在救援井中，位于井口與防噴器(BOP)之間，作為一個(gè)水下注入歧管，為泵送壓井泥漿提供額外的入口。每一個(gè)入口都配備有雙重故障防護(hù)隔絕閥，為救援井提供必要的壓力控制手段。在壓井作業(yè)期間，位于救援井鉆井平臺(tái)附近的一艘或多艘高壓泵船，將利用高壓柔性管線連接至RWIS入口，以提供額外的泥漿泵入。RWIS可以通過空運(yùn)、陸運(yùn)以及海運(yùn)快速部署到世界任何地區(qū)，適用性極強(qiáng)。Trendsetter公司表示，RWIS已被要求用于挪威與美國(guó)的特殊油井，并已經(jīng)于2016年底成功投入商業(yè)應(yīng)用。

自2010年以來(lái)，Trendsetter工程公司與Add能源公司已在多個(gè)項(xiàng)目上合作。2015年，兩家公司合作的目的是進(jìn)一步開發(fā)有利于能源行業(yè)的技術(shù)，提高安全性，提高鉆井作業(yè)的經(jīng)濟(jì)效益，從而開發(fā)出了RWIS。利用Trendsetter公司的海底工程經(jīng)驗(yàn)以及Add 能源公司針對(duì)井噴、井控事故的專家現(xiàn)場(chǎng)支持，兩家公司為井底動(dòng)態(tài)壓井的救援井應(yīng)用，研發(fā)出突破性的工具。

RWIS是一種增加單口救援井流量的裝置。在許多情況下，相比于鉆探多口救援井，這是更安全且且更具挑戰(zhàn)性的選擇。RWIS位于救援井口與防噴器之間，它為多艘泵船提供了入口，這些泵船通過柔性管線進(jìn)行水力連接，并將壓井液注入救援井。對(duì)于壓井需求更低的井噴，RWIS仍可選擇更淺的相交點(diǎn)深度，以節(jié)省作業(yè)時(shí)間并限制溢流量。當(dāng)動(dòng)態(tài)壓井需求可能會(huì)影響到井設(shè)計(jì)時(shí)，RWIS可以在套管、完井作業(yè)以及油田開發(fā)方面節(jié)省大量成本。

RWIS是一種獲得專利的水下專業(yè)設(shè)備，使作業(yè)者能夠通過一口救援井安全有效地阻止高產(chǎn)油藏的井噴。RWIS通過移除了限制性節(jié)流以及水面船只至海床的管線所造成的瓶頸，增加了井噴井注入壓井泥漿的泵排量。

RWIS的設(shè)計(jì)與制造目的是提高泵入效率，通過每分鐘向一口救援井泵入超過200桶的壓井泥漿，大大提高單口救援井的泵入能力，這是常規(guī)救援井可實(shí)現(xiàn)的壓井泵速的四倍。相對(duì)于需要多口救援井的方法，利用多艘泵船的方法擁有顯著優(yōu)勢(shì)。

RWIS除了能夠確保單口救援井的應(yīng)急措施之外，還可使作業(yè)者優(yōu)化經(jīng)濟(jì)效益，并幫助他們解鎖通常不會(huì)被批準(zhǔn)的項(xiàng)目。在應(yīng)用RWIS時(shí)，作業(yè)者能夠通過增加井筒的完井尺寸、降低資本支出成本以及產(chǎn)量最大化，來(lái)遵守法規(guī)并減少滿足產(chǎn)量目標(biāo)所需的井?dāng)?shù)。

RWIS的優(yōu)勢(shì)

在項(xiàng)目開發(fā)期間，RWIS增加井筒的完井尺寸，使井筒流量最大化，同時(shí)通過更少的井筒即可滿足產(chǎn)量目標(biāo)，確保項(xiàng)目在預(yù)算范圍內(nèi)開發(fā)。在油氣溢流期間，通過大排量向井噴井中泵入壓井液，實(shí)現(xiàn)快速壓井，通過簡(jiǎn)化方案提高壓井作業(yè)的安全性，將泵送系統(tǒng)與儲(chǔ)罐從鉆井平臺(tái)轉(zhuǎn)移至專用的泵船，確保不需要調(diào)整鉆機(jī)，且不會(huì)妨礙一級(jí)井控設(shè)備，同時(shí)得益于重量與尺寸，可以輕松調(diào)動(dòng)與運(yùn)輸。

案例研究

根據(jù)安全指導(dǎo)方針，Add能源公司的一位客戶要求對(duì)一口近海淺層氣井進(jìn)行井噴應(yīng)急處理。這類井的井噴壓井往往面臨許多挑戰(zhàn)，包括在動(dòng)態(tài)壓井期間僅有很窄的深度窗口，來(lái)建立靜液柱壓力與摩擦壓耗，并且需要高壓差來(lái)平衡油藏壓力。對(duì)于最嚴(yán)重的井噴情況，使用RWIS可以確保用一口救援井就能控制住這些井。

Add能源公司的井控與流體模擬專家利用設(shè)計(jì)井身結(jié)構(gòu)以及預(yù)測(cè)儲(chǔ)層性質(zhì)，模擬了最嚴(yán)重的井噴情況。模擬中使用了一口安裝有RWIS的救援井，將壓井泥漿泵入目標(biāo)井筒。使用不同的壓井泥漿與硬件配置進(jìn)行了多次迭代，以實(shí)現(xiàn)成功的壓井。

最嚴(yán)重情況下，該井的氣體排放量約30億立方英尺/天，動(dòng)態(tài)壓井期間使用RWIS，以230 bpm的總速率泵送壓井泥漿。第二口救援井連接至RWIS泵速達(dá)到180 bpm，而第一口救援井僅有50 bpm；對(duì)硬件配置進(jìn)行了HHP規(guī)定、泵曲線、額定壓力、腐蝕速度、疲勞極限、系統(tǒng)冗余以及其他約束的評(píng)估，研究表明，在這種情況下，可以通過單口救援井壓住最壞情況下的高產(chǎn)井的井噴。

Trendsetter Engineering and Add Energy have combined their expertise in well control engineering and equipment design to develop the relief well injection spool (RWIS).

The RWIS is designed to enable pumping of up to 200 barrels per minute of kill mud through a single relief well utilizing multiple vessels as opposed to the conventional method of multiple relief wells.

The RWIS is designed to be installed on a relief well prior to intersecting the blowout well and would be positioned between the wellhead and the blowout preventer (BOP), becoming a subsea injection manifold providing additional inlets for pumping kill mud. Each of these inlets is equipped with dual fail-safe barrier valves to provide the necessary means of pressure containment in the relief well. During the well kill operation, one or more high-pressure pumping vessels located near the relief well rig will be connected to the RWIS inlets using high pressure flexible flowlines to provide the additional mud fluid. The RWIS can be rapidly deployed by air, ground and marine freight to any region of the world.

The RWIS has already been requested for specific wells in Norway and U.S.A, and should be available to the market by the end of 2016, the company said.

Since 2010, Trendsetter Engineering and Add Energy have teamed to work together on multiple projects. In 2015, the companies came together with the aim to further develop technology that benefits the energy industry by increasing safety and allowing for more cost-effective drilling operations, resulting in the development of the Relief Well Injection Spool (RWIS). Utilizing both Trendsetter’s subsea engineering experience and Add Energy’s expert on-site advisory for blowouts and well control incidents, the two companies created a breakthrough tool for dynamic bottom kill relief well applications.?

The RWIS is a device that increases the flow capacity of a single relief well. In? many scenarios, this is a safer and less challenging option to drilling multiple relief wells. The RWIS sits between the relief wellhead and the BOP, and it provides inlets for multiple pumping vessels to hydraulically connect via flexible lines and inject kill fluid into the relief well (see figure). For blowouts where the kill requirements are lower, the RWIS may still provide benefits by allowing a shallower intersect that saves time and limits the spill volumes. In cases where the dynamic kill requirements drive the well design, the RWIS may provide significant savings on the casing, completion and field development.?

The Relief Well Injection Spool (RWIS) is a patented specialist subsea equipment that enables operators to stop a blowout from prolific reservoirs safely and efficiently via a single relief well. This is made possible with the RWIS by increasing the pump rate of kill mud into the blowing well by removing the bottle-neck caused by restrictive choke and kill lines from the surface vessel to the seabed.

The RWIS has been designed and built to significantly increase the pumping capacity of a single relief well by pumping in excess of 200 barrels of kill mud per minute through a single relief well, four times as much kill fluid as typically achievable. A significant advance for the industry which utilizes multiple vessels as opposed to the alternative method requiring multiple relief wells.

In addition to the RWIS assuring single relief well contingency, the RWIS also enables operators to optimize well economics and help unlock projects that wouldn’t normally be sanctioned. In purchasing access rights to the RWIS, operators are able to comply with legislation and reduce the number of wells required to meet production targets by increasing the completion size of the well bore, reducing CAPEX costs and maximizing production.

Benefits of using the RWIS:

During project development:

Complies with legislation and company policy by guaranteeing single relief well contingencyEnables the completion size of the well bore to be increased, maximizing well flow ratesAllows production targets to be met with fewer wells, assuring the project can be developed within budgetHelps to build a business case for project sanction

During a hydrocarbon release:

Enables rapid kill of a blowing well – through high rate pumping of kill fluids into a blowing wellImproves safety of a well kill operation through a simplified solutionEnables relocation of pumping and storage off the rig to dedicated pumping vesselsEnsures no rig modifications are required or interference with primary well control equipmentAllows easy mobilization and transportation due to weight and size

PROJECT SHOWCASE

Add Energy was approached by a client who, according to company safety guidelines, requested a blowout-contingency study for an offshore shallow gas well.

A blowout intervention for these types of wells are often faced with many challenges including a narrow depth window to build hydrostatic and frictional pressure during a dynamic kill combined with high pressure differential to balance the reservoir pressure. For a worst-case blowout scenario, using a relief well injection spool (RWIS) may ensure the ability to bring such wells under control with a single relief well.?

WHAT WE DID

The Add Energy well-control and flow-simulation specialist modeled the worst-case-blowout scenario using the planned wellbore schematic and predicted reservoir properties. A single relief well with an RWIS installed on its wellhead was used in the simulations to pump kill mud into the target wellbore. Several iterations were made using different kill muds and hardware configurations to achieve a successful kill.

RESULTS

A worst-case gas discharge of around 3 Billion SCF/DayA dynamic kill using the RWIS to pump a heavy mud at a combined rate of 230 bpm50 bpm down primary relief well and 180 bpm down secondary relief well connected to the RWISHardware configuration was evaluated for hhp requirements, pump curves, pressure ratings, erosional velocities, fatigue limitations, system redundancy and other constraintsThe study demonstrated that a prolific worst-case blowout scenario could in this case be killed with a single relief well

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